WO2009122938A1 - Substrate for thin film solar cell, manufacturing method thereof, and thin film solar cell using thereof - Google Patents

Substrate for thin film solar cell, manufacturing method thereof, and thin film solar cell using thereof Download PDF

Info

Publication number
WO2009122938A1
WO2009122938A1 PCT/JP2009/055623 JP2009055623W WO2009122938A1 WO 2009122938 A1 WO2009122938 A1 WO 2009122938A1 JP 2009055623 W JP2009055623 W JP 2009055623W WO 2009122938 A1 WO2009122938 A1 WO 2009122938A1
Authority
WO
WIPO (PCT)
Prior art keywords
titanium oxide
substrate
oxide film
film
solar cell
Prior art date
Application number
PCT/JP2009/055623
Other languages
French (fr)
Japanese (ja)
Inventor
村田正義
Original Assignee
Murata Masayoshi
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Murata Masayoshi filed Critical Murata Masayoshi
Publication of WO2009122938A1 publication Critical patent/WO2009122938A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • C23C16/407—Oxides of zinc, germanium, cadmium, indium, tin, thallium or bismuth
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C16/00—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes
    • C23C16/22—Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes characterised by the deposition of inorganic material, other than metallic material
    • C23C16/30—Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
    • C23C16/40—Oxides
    • C23C16/405—Oxides of refractory metals or yttrium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • H01L31/022466—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers
    • H01L31/022483—Electrodes made of transparent conductive layers, e.g. TCO, ITO layers composed of zinc oxide [ZnO]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H01L31/1884—Manufacture of transparent electrodes, e.g. TCO, ITO
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy

Definitions

  • the present invention relates to a thin film solar cell substrate, a method for producing the same, and a thin film solar cell using the same.
  • Transparent electrodes used in thin film solar cells such as amorphous silicon solar cells and tandem thin film silicon solar cells (a combination of amorphous silicon cells and microcrystalline silicon cells) have electrical properties that have high conductivity, and Optical characteristics are required to have high transparency and light confinement effect (uneven structure of the film). Furthermore, it is required not to change color when exposed to plasma, that is, to have excellent plasma resistance.
  • the plasma resistance is low, for example, when a photoelectric conversion layer for a thin film silicon solar cell is manufactured by a plasma CVD method, the film surface of the transparent electrode is reduced by the plasma and changed to black. As a result, the incident light is absorbed in the blackened portion, the amount of light incident on the photoelectric conversion layer is reduced, and power generation efficiency is reduced.
  • a transparent electrode mainly composed of tin oxide (SnO 2) manufactured by a thermal CVD method described in Patent Document 1 Japanese Patent Laid-Open No. 2003-81633
  • Patent Document 1 Japanese Patent Laid-Open No. 2003-81633
  • ZnO zinc oxide
  • the thermal CVD method requires a high-temperature process of 550 to 650 ° C. to manufacture a transparent electrode mainly composed of tin oxide (SnO 2). Therefore, when tempered glass is used for the substrate, the tempered glass is tempered by the high temperature process, and is usually transformed into glass. Therefore, when tempered glass cannot be used for a substrate and a large area glass substrate is used, it is necessary to increase the glass thickness (weight increase) in order to ensure the strength of the glass substrate. As a result, the weight increases by 4 to 5 times compared to the case where tempered glass is used for the substrate, which is not only inconvenient but also increases in manufacturing cost.
  • Patent Document 2 Patent No. 3215128
  • Patent Document 3 Japanese Patent Laid-Open No. 2000-150928
  • Patent Document 4 Japanese Unexamined Patent Application Publication No. 2005-311292
  • Japanese Patent Application Laid-Open No. 2001-015787 Japanese Patent Application Laid-Open No. 2001-015787.
  • Patent Document 2 Japanese Patent No. 3215128 describes a method for producing a transparent electrode containing zinc oxide (ZnO) as a main component by sputtering. This method is characterized in that sputtering is performed using a ZnO target doped with Al at a sputtering gas pressure of 2 Pa or more and a substrate temperature of 250 ° C. or more.
  • the transparent electrode mainly composed of zinc oxide (ZnO) produced by this method has a columnar or granular agglomerate having a size of 0.1 to 10 ⁇ m and a void of 0.1 to 10 ⁇ m on the film surface.
  • a ZnO thin film doped with Al in which the light transmittance of the film depends on the light incident angle.
  • columnar or granular agglomerates having a size of 0.1 to 10 ⁇ m form voids of 0.1 to 10 ⁇ m on the film surface. Therefore, it is not suitable for a transparent electrode for a thin film silicon solar cell. That is, when a p-type semiconductor film (thickness is, for example, 5 to 20 nm) constituting a photoelectric conversion layer is formed on the transparent electrode film having the voids, A p-type semiconductor film is not formed.
  • the quality of the obtained p-type semiconductor film is affected by the structure of the void portion. As a result, there is a problem that it is difficult to manufacture a p-type semiconductor film formed on the surface of the transparent electrode film with high quality and good reproducibility.
  • Patent Document 3 Japanese Patent Application Laid-Open No. 2000-150928
  • an aluminum film is formed on a light-transmitting substrate by a sputtering method, the aluminum film is partially etched away, and the surface thereof is roughened.
  • the aluminum film is oxidized or nitrided by heating in a nitrogen atmosphere to change into a crystallized aluminum oxide or aluminum nitride aluminum compound film, and transparent conductive material made of zinc oxide or tin oxide is formed by sputtering.
  • a method for forming a transparent electrode substrate by forming a conductive film is described. This method has the following characteristics.
  • a transparent electrode substrate formed by forming a transparent conductive film on a light-transmitting substrate by a sputtering method an uneven aluminum compound film is provided between the light-transmitting substrate and the transparent conductive film. It is characterized by. Further, in a method of forming a transparent electrode substrate formed by forming a transparent conductive film on a light-transmitting substrate by a sputtering method, a step of forming an aluminum film on the light-transmitting substrate, and etching the formed aluminum film And a step of changing the aluminum film into an aluminum compound film, and a step of forming a transparent conductive film on the aluminum compound film by a sputtering method.
  • the manufacturing process has four steps, that is, the step of forming an aluminum film on the translucent substrate, the step of etching the formed aluminum film to make it uneven, and the aluminum film as an aluminum compound film.
  • the process is complicated and includes a process of forming a transparent conductive film on the aluminum compound film by sputtering. This means that when applied to a practical production line, the introduction cost of the apparatus constituting the manufacturing process increases and the running cost increases. In general, it is known that as the number of manufacturing processes increases, the yield of products decreases. As a result, there is a problem that the cause of the increase in production cost is held.
  • Patent Document 4 Japanese Patent Laid-Open No. 2005-311292 describes a method using a low-pressure thermal CVD method (or a method called MOCVD method, Metal-Organic Chemical Vapor Deposition).
  • MOCVD method Metal-Organic Chemical Vapor Deposition
  • light-transmitting fine particles silicon: SiO2, titanium oxide: TiO2, aluminum oxide: Al2O3, zirconium oxide: ZrO2, indium tin oxide: ITO, or magnesium fluoride: MgF2
  • the ZnO film is formed on the light-transmitting fine particles by low-pressure thermal CVD. This method has the following characteristics.
  • a thin film solar cell substrate comprising a light-transmitting insulating substrate and a transparent electrode layer containing at least zinc oxide deposited on the light-transmitting insulating substrate, the light-transmitting insulating substrate being the transparent electrode layer
  • the side interface has fine surface irregularities having a root mean square roughness of 5 to 50 nm, and the convex portions are composed of phases.
  • the transparent electrode layer has a thickness of 1 ⁇ m or more.
  • the translucent insulating substrate is a laminate of a translucent substrate having a smooth surface and a translucent underlayer, and the translucent underlayer has an average particle diameter of 10 nm or more and less than 100 nm. It contains a light-sensitive fine particle and a light-transmitting binder.
  • the transparent insulating substrate is deposited at a temperature of 150 ° C. or more and containing at least zinc oxide.
  • a translucent underlayer composed of a translucent binder and translucent fine particles is disposed on a glass substrate, and the translucent layer A transparent electrode layer is laminated on the base layer.
  • a translucent binder containing a solvent such as silicon oxide, aluminum oxide, titanium oxide, and zirconium oxide
  • translucent fine particles are formed on a translucent insulating substrate. It is necessary to apply a dipping method, a spin coating method, a spray method, or the like and immediately dry the coated thin film after the coating operation is completed.
  • the problem of whether the adhesive force between the translucent underlayer composed of a translucent binder containing a solvent and translucent fine particles and the translucent substrate is sufficiently strong, and high temperature (150 ° C. And the like) whether the adhesive strength does not decrease when exposed to the above. Furthermore, there is a problem of whether long-term stability is good.
  • the solvent is removed from the translucent binder containing the solvent and the translucent fine particles in the heating and drying step of the coated thin film, voids are formed in the portion where the solvent is present, and the porous film is generally porous. It becomes a state. This porous state becomes an impurity generation source in the manufacturing process of the power generation film by the plasma CVD method. As a result, there may be a problem that it is difficult to manufacture a solar cell with high power generation efficiency.
  • Patent Document 5 Japanese Patent Laid-Open No. 2001-015787 uses a substrate with a transparent conductive film having a surface uneven structure, which can be formed at high speed by a sputtering method, and has high productivity, and a manufacturing method, and the substrate with a transparent conductive film.
  • a solar cell is described.
  • the point of idea is that titanium oxide and zinc oxide are laminated on a substrate by sputtering, and has the following characteristics. That is, it is a method for producing a substrate with a transparent conductive film in which a transparent conductive film mainly composed of zinc oxide is laminated on a film mainly composed of titanium oxide formed on the substrate.
  • the present invention is characterized in that it is a substrate with a transparent conductive film in which a transparent conductive film mainly composed of zinc oxide is laminated in contact with a film mainly composed of titanium oxide formed on the substrate. Moreover, it is a solar cell in which a photoelectric conversion layer and an electrode layer are formed in this order on a transparent conductive film containing zinc oxide as a main component of the substrate with the transparent conductive film. Moreover, the base
  • substrate with a transparent conductive film of the said patent document 5 is produced as follows, for example.
  • a TiO2 film having a thickness of 0.5 to 200 nm is formed on a glass substrate by an oxidation reactive sputtering method using a Ti target, and then a conductive oxide target mainly composed of zinc oxide is formed.
  • the zinc oxide transparent conductive film is formed in contact with the TiO 2 film by sputtering in argon gas.
  • Patent Document 5 Japanese Patent Laid-Open No. 2001-015787 shows the following in general.
  • A From the viewpoint of obtaining a solar cell with high conversion efficiency, the titanium oxide film is a transparent film having high light transmittance.
  • a TiO2 film or another component for example, SiO2, A film doped with Al2O3, Fe2O3 is mentioned.
  • the film thickness is preferably 0.5 to 200 nm, particularly 1 to 10 nm.
  • the form of the titanium oxide film may be either a continuous film or a discontinuous film.
  • As the oxide target for forming the titanium oxide film TiO2 or TiO2-x is used.
  • TiO2 is not conductive, it is limited to a high frequency (RF) sputtering method, and in the case of TiO2-x. Is conductive, so that either direct current sputtering or radio frequency (RF) sputtering may be used.
  • the substrate temperature when the titanium oxide film is formed by sputtering is preferably 0 to 600 ° C. In particular, a temperature of 20 to 400 ° C. is preferable.
  • B Regarding the zinc oxide film, it is preferable that the surface uneven state has an arithmetic average roughness defined by JIS B0601 of 15 to 150 nm.
  • examples of the zinc oxide-based transparent conductive film include films in which ZnO is doped with another component (for example, one or more selected from the group consisting of B, Al, Ga, In, Si, and Ti) as a dopant. Yes.
  • another component for example, one or more selected from the group consisting of B, Al, Ga, In, Si, and Ti.
  • Al or Ga is preferable.
  • the dopant content is preferably such that the total amount of dopant relative to the total amount of dopant and zinc (ZnO) is 0.01 to 10 atomic%.
  • the film thickness of the zinc oxide-based transparent conductive film is preferably 100 to 3000 nm. In particular, 100 to 1000 nm is preferable. When it is thinner than 100 nm, the uneven structure is difficult to appear. On the other hand, if it is thicker than 3000 nm, it takes time to form a film, which is not practical, and the amount of light absorption increases, resulting in a large loss of light energy.
  • a zinc oxide type transparent conductive film it is preferable that it is a continuous film (film
  • the substrate temperature when forming the zinc oxide-based transparent conductive film is preferably 0 to 600 ° C. In particular, a temperature of 20 to 400 ° C. is preferable.
  • the sputtering pressure at the time of sputtering the zinc oxide-based transparent conductive film is not particularly limited, and is generally preferably 0.01 to 1.4 Pa at which stable discharge is possible.
  • a substrate such as a substrate on which a film (for example, a silicon oxide film) for preventing diffusion of an alkali component in a glass substrate is formed may be used.
  • This method has the following effects.
  • the titanium oxide film is a substantially flat film without a particularly large uneven structure.
  • the titanium oxide film affects the crystal growth of the zinc oxide-based transparent conductive film laminated on and in contact with the titanium oxide film, and as a result, a zinc oxide crystal having a large crystal grain in which the crystal growth is promoted grows. Due to the crystal grains, the surface of the zinc oxide-based transparent conductive film becomes uneven.
  • the zinc oxide-based transparent conductive film has a roof-like uneven shape, is suitable as an incident side electrode of a solar cell, and has a high light confinement effect.
  • the roof has a relatively gentle slope, when an amorphous silicon layer is laminated on the transparent conductive film, there are very few portions where the amorphous silicon layer is not formed, and it is a continuous suitable as a solar cell. It becomes an amorphous silicon layer.
  • the titanium oxide film also has an effect of preventing diffusion of alkali and moisture from the substrate glass, and can prevent deterioration of the zinc oxide-based transparent conductive film. As a result, the reliability of the solar cell using the substrate on which the titanium oxide film and the transparent conductive film are stacked is improved.
  • Patent Document 5 Japanese Patent Laid-Open No. 2001-015787
  • the target material is expensive and the use efficiency of the target material in the sputtering method is low.
  • the manufacturing cost of the solar cell substrate manufactured using the method is high.
  • Patent Document 5 Japanese Patent Application Laid-Open No. 2001-015787 describes a method for forming a titanium oxide film and a method for forming a transparent conductive film mainly composed of zinc oxide using a sputtering method.
  • a method or apparatus other than the sputtering method is mentioned. That is, there is no mention of a method or apparatus that may have a lower manufacturing cost than the sputtering method. Further, there is no mention of controlling the characteristics of titanium oxide in the film thickness direction.
  • JP 2003-81633 A Japanese Patent No. 3215128 JP2000-150928A JP 2005-311292 A JP 2001-015787 A
  • a transparent electrode mainly composed of tin oxide (SnO2) by a thermal CVD method has been put into practical use, but there is a problem that it is difficult to reduce the manufacturing cost.
  • Recently, in the thin film solar cell industry there has been a strong demand for an innovative reduction in production cost by adopting a large area substrate with a substrate size of the 8th generation (2.2 mx 2.6 m).
  • the conventional thermal CVD method is difficult to cope with the 8th generation substrate because it involves technical difficulties peculiar to high temperature processes (increased glass substrate thickness, glass breakage due to non-use of tempered glass, etc.). There is a problem that there is.
  • Patent Documents 2 to 5 which are expected as new methods and apparatuses in place of the transparent electrode manufacturing method and manufacturing apparatus mainly composed of tin oxide (SnO2) by the thermal CVD method.
  • SnO2 tin oxide
  • the present invention has been made in view of the above problems, and can be easily formed into a large area, and is a low-cost raw material such as an organometallic material such as trimethyl zinc, triethyl zinc, diethyl zinc, etc.
  • An object is to create a new method and apparatus using high-frequency plasma CVD technology that can be used as a raw material, and to provide a technology related thereto.
  • a thin film solar cell substrate in which an amorphous titanium oxide film, a crystalline titanium oxide film, and a crystalline zinc oxide film are laminated on a transparent insulating substrate, a manufacturing method thereof, and a thin film solar cell using the same The purpose is to provide.
  • a substrate for a thin film solar cell includes a light-transmitting insulating substrate (2) and at least a titanium oxide film layer deposited on the light-transmitting insulating substrate ( 3a) and a thin film solar cell substrate (1a) comprising a transparent electrode layer including a zinc oxide film layer (5), wherein the titanium oxide film layer (3a) is formed of an amorphous titanium oxide film layer (4a) and a crystal. It has a two-layer structure composed of a quality titanium oxide film layer (4b).
  • a substrate for a thin-film solar cell includes a translucent insulating substrate (2) and at least titanium oxide deposited on the translucent insulating substrate.
  • a thin film solar cell substrate (1b) comprising a transparent electrode layer including a film layer (3b) and a zinc oxide film layer (5), wherein the titanium oxide film layer (3b) is an amorphous titanium oxide film layer (4a).
  • a substrate for a thin-film solar cell includes a translucent insulating substrate (2) and at least titanium oxide deposited on the translucent insulating substrate.
  • a thin film solar cell substrate (1c) comprising a transparent electrode layer including a film layer (3c) and a zinc oxide film layer (5), wherein the titanium oxide film layer (3c) comprises amorphous titanium oxide and microcrystalline oxide It has a two-layer structure composed of a mixed phase titanium oxide film layer (4c) mixed with titanium and a crystalline titanium oxide film layer (4b).
  • the thin film solar cell substrate according to the fourth aspect of the present invention is characterized in that the zinc oxide film layer (5) has crystallinity.
  • a thin film solar cell substrate has a thickness of the amorphous titanium oxide film layer (4a) of 1 nm to 150 nm and the crystalline material.
  • the titanium oxide film layer (4b) has a thickness of 5 nm to 250 nm.
  • the substrate for a thin film solar cell according to the sixth aspect of the present invention is the thickness of the mixed phase titanium oxide film layer (4c) in which the amorphous titanium oxide and the microcrystalline titanium oxide are mixed. Is 10 nm to 100 nm.
  • a method for manufacturing a thin-film solar cell substrate according to a seventh aspect of the present invention is a method for manufacturing the thin-film solar cell substrate (1a, 1b, 1c),
  • the amorphous titanium oxide film layer (4a), the crystalline titanium oxide film layer (4b) and the zinc oxide film layer (5) are all manufactured using a high-frequency plasma CVD apparatus.
  • a method for manufacturing a thin-film solar cell substrate according to an eighth aspect of the present invention includes the amorphous titanium oxide film layer (4a) and the crystalline titanium oxide film layer (4b). ) Is manufactured using a high-frequency plasma CVD apparatus, and the zinc oxide film layer (5) is manufactured using a sputtering apparatus.
  • a method for manufacturing a thin film solar cell substrate relates to the amorphous titanium oxide film layer (4a) and the crystalline titanium oxide film layer (4b).
  • ) Is manufactured at a temperature of 250 to 450 ° C. of the translucent insulating substrate (2), and the zinc oxide film layer (5) is manufactured at a temperature of 150 to 450 ° C. of the translucent insulating substrate (2). It is characterized by being.
  • the amorphous titanium oxide film layer has a temperature 250 of the translucent insulating substrate (2).
  • the crystalline titanium oxide film layer (4b) is manufactured at a temperature of 250 to 450 ° C. of the translucent insulating substrate (2), and the zinc oxide film layer (5) is the translucent film.
  • the insulating insulating substrate (2) is manufactured at a temperature of 150 to 450 ° C.
  • a method for manufacturing a thin film solar cell substrate according to an eleventh aspect of the present invention includes the amorphous titanium oxide film layer (4a) and the crystalline titanium oxide film layer (4b). ) Using a high-frequency plasma CVD method, at least a mixed gas of titanium tetraisopropoxide and oxygen is used as a raw material, and the temperature of the translucent insulating substrate (2) is 250 to 450 ° C. It is characterized by being.
  • a method for manufacturing a thin film solar cell substrate according to a twelfth aspect of the present invention includes the amorphous titanium oxide film layer (4a) and the crystalline titanium oxide film layer (4b). ),
  • the temperature of the translucent insulating substrate (2) is set to 250 ° C. to 450 ° C., and at least a mixed gas of titanium tetraisopropoxide and oxygen is used as a raw material.
  • the amorphous titanium oxide film layer (4a) formed at the initial deposition stage is used as a barrier layer for impurities from the translucent insulating substrate (2), and the amorphous titanium oxide film layer A crystalline titanium oxide film layer (4b) formed using (4a) as a base is used as a base layer in forming the zinc oxide film layer (5).
  • a thin film solar cell according to a thirteenth aspect of the present invention is characterized in that at least amorphous silicon or microcrystalline silicon is contained in the photoelectric conversion layers (7, 13). .
  • a thin film solar cell in which amorphous titanium oxide, crystalline titanium oxide, and crystalline zinc oxide with a large crystal grain size doped with Ga or Al are laminated on a light-transmitting insulating substrate.
  • a substrate can be manufactured.
  • this thin film solar cell substrate as a transparent electrode of an amorphous silicon solar cell and a tandem solar cell, it is possible to manufacture a solar cell having high photoelectric conversion efficiency.
  • the manufacturing cost of the thin film solar cell can be innovatively reduced.
  • 1 is a structural diagram schematically showing a cross section of a thin-film solar cell substrate according to a first embodiment of the present invention.
  • 1 is an apparatus configuration diagram schematically showing a high-frequency plasma CVD apparatus for manufacturing a titanium oxide (TiO 2) film according to a first embodiment of the present invention.
  • 1 is an apparatus configuration diagram schematically showing a high-frequency plasma CVD apparatus for manufacturing a zinc oxide (ZnO) film according to a first embodiment of the present invention.
  • the substrate temperature is a low temperature range (room temperature to 250 ° C.), and the film formation time is the same as that when the substrate is glass.
  • Explanatory drawing which shows the relationship between the thickness of a film and film quality.
  • the substrate temperature is in the middle temperature range (250 to 350 ° C.), and the film formation time is the same as that in the case where the substrate is glass.
  • Explanatory drawing which shows the relationship between the thickness of a film and film quality.
  • the substrate temperature is in a high temperature range (350 to 450 ° C.) and the film is formed with the film formation time in the case where the substrate is glass.
  • Explanatory drawing which shows the relationship between the thickness of a film and film quality.
  • the substrate temperature is in a high temperature range (350 to 450 ° C.) and the base is amorphous titanium oxide or amorphous oxide.
  • Explanatory drawing which shows the relationship between the mixed phase of titanium and microcrystalline titanium oxide, or the film formation time in crystalline titanium oxide, the thickness of the film formed, and film quality.
  • Explanatory drawing which shows the relationship between thickness and film quality.
  • FIG. 5 is a structural diagram schematically showing a cross section of a thin film solar cell substrate according to a second embodiment of the present invention.
  • FIG. 5 is a structural diagram schematically showing a cross section of a thin-film solar cell substrate according to a third embodiment of the present invention.
  • 1a Substrate for thin film solar cell according to the first embodiment of the present invention, 2 ... Translucent insulating substrate, 4a ... amorphous titanium oxide layer, 4b ... crystalline titanium oxide layer, 4c: mixed phase titanium oxide film of amorphous titanium oxide and crystalline titanium oxide, 5 ... crystalline zinc oxide (ZnO) film layer, 100 ... Vacuum container, 101 ... Ungrounded first electrode, 103 ... a second electrode grounded; 120a: raw material for titanium oxide film, 120b ... Raw material of zinc oxide film, 120c ... doping material of zinc oxide film, 135: Transmitter, 138a, 138b... First and second power amplifiers, 139a, 139b... First and second matching units.
  • FIG. 1 is a structural view schematically showing a cross section of a thin film solar cell substrate according to a first embodiment of the present invention.
  • FIG. 2 is an apparatus configuration diagram showing an outline of a high-frequency plasma CVD apparatus for producing a titanium oxide (TiO 2) film according to the first embodiment of the present invention.
  • FIG. 3 is an apparatus configuration diagram showing an outline of a high-frequency plasma CVD apparatus for manufacturing a zinc oxide (ZnO) film according to the first embodiment of the present invention.
  • FIG. 1 is a structural view schematically showing a cross section of a thin film solar cell substrate according to a first embodiment of the present invention.
  • FIG. 2 is an apparatus configuration diagram showing an outline of a high-frequency plasma CVD apparatus for producing a titanium oxide (TiO 2) film according to the first embodiment of the present invention.
  • FIG. 3 is an apparatus configuration diagram showing an outline of a high-frequency plasma CVD apparatus for manufacturing a zinc oxide (ZnO) film according to the first embodiment of the present invention.
  • FIG. 4 shows the film formation time when the substrate temperature is low (room temperature to 250 ° C.) and the substrate is glass when manufacturing the titanium oxide film by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention. It is explanatory drawing which shows the relationship between the thickness of the film
  • FIG. 5 shows the film formation time when the substrate temperature is in the intermediate temperature range (250 to 350 ° C.) and the substrate is glass when the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention. It is explanatory drawing which shows the relationship between the thickness of the film
  • FIG. 6 shows the film formation time in the case where the substrate temperature is high (350 to 450 ° C.) and the substrate is glass when the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention. It is explanatory drawing which shows the relationship between the thickness of the film
  • FIG. 7 shows a substrate temperature in the high temperature region (350 to 450 ° C.) when the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention, and the base is amorphous titanium oxide.
  • FIG. 8 shows the film formation time and the manufacturing time when the substrate temperature is about 200 to 400 ° C. and the base is crystalline titanium oxide when the zinc oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention.
  • FIG. 9 is an explanatory diagram of application of the thin film solar cell substrate according to the first embodiment of the present invention to the manufacture of an amorphous silicon solar cell.
  • FIG. 10 is an explanatory diagram of application of the thin film solar cell substrate according to the first embodiment of the present invention to manufacture of a tandem thin film solar cell.
  • a thin film solar cell substrate 1a according to the first embodiment of the present invention includes a translucent insulating substrate 2 and a titanium oxide layer 3a (described later from an amorphous titanium oxide layer 4a and a crystalline titanium oxide layer 4b). And a crystalline zinc oxide (ZnO) film layer 5.
  • reference numeral 2 denotes a translucent insulating substrate, for example, a glass substrate having a thickness of 4 to 5 mm.
  • Reference numeral 3a denotes a titanium oxide layer, which is composed of two layers, an amorphous titanium oxide layer 4a and a crystalline titanium oxide layer 4b.
  • the amorphous titanium oxide layer 4a and the crystalline titanium oxide layer 4b are made of titanium tetraisopropoxide: Titanium-Tetra-Iso-Propoxide (here, TTIP) using argon gas or hydrogen gas as a carrier gas. ) And oxygen as a main raw material, and is formed by a high-frequency plasma CVD apparatus.
  • Reference numeral 5 denotes a crystalline zinc oxide (ZnO) film layer.
  • this crystalline zinc oxide (ZnO) film layer uses argon gas or hydrogen gas as a carrier gas, and uses trimethylzinc (CH 3 ) 3 Zn or triethylzinc (C 2 H 5 ) 3 Zn and oxygen.
  • the mixed gas is used as a main raw material to form a film by a high frequency plasma CVD apparatus.
  • the crystalline zinc oxide (ZnO) film layer 5 may be formed by using a sputtering apparatus.
  • trimethylgallium (CH 3 ) 3 Ga, triethylgallium (C 2 H 5 ) 3 Ga, Trimethylaluminum (CH 3 ) 3 Al, triethylaluminum (C 2 H 5 ) 3 Al, or the like is used.
  • symbol 100 is a vacuum vessel.
  • the vacuum vessel 100 is provided with a pair of electrodes for converting a source gas to be described later into plasma, that is, a non-grounded first electrode 101 and a grounded second electrode 103 containing a substrate heater 102 (not shown).
  • Reference numeral 101 denotes a first electrode, which is fixed to the vacuum vessel 100 via an insulator support member 104 and a gas mixing box 105 (not shown).
  • the first electrode 101 has a rectangular flat plate shape, and is disposed to face a second electrode 103 described later.
  • the specific size is, for example, an external dimension of length 1.5 mx width 0.3 mx thickness 20 mm.
  • the first electrode 101 and the gas mixer 105 have gas shower holes 106 and 107 through which the source gas is ejected, respectively.
  • the holes 106 and 107 have a diameter of about 0.4 to 1 mm, for example, a diameter of about 0.7 mm, and a large number of holes 106 and 107 are set.
  • the gas shower hole 107 has a function of rectification for uniformly supplying oxygen gas, which will be described later, between the pair of electrodes 101 and 103 through the gas shower hole 106.
  • the gas shower hole 106 is a rectifier for uniformly supplying a mixed gas of a carrier gas and titanium tetraisopropoxide (hereinafter referred to as TTIP), which will be described later, and the oxygen gas between the pair of electrodes 101 and 103. It has the function of.
  • Reference numeral 103 denotes a second electrode which includes a substrate heater 102 (not shown), and the temperature of the substrate 108 placed thereon can be set to an arbitrary temperature within a range of 100 to 450 ° C.
  • the second electrode 103 can include a pipe through which a refrigerant is passed to control the surface temperature of the second electrode 103.
  • the second electrode 103 has a rectangular flat plate shape and is disposed to face the first electrode 101.
  • the specific size is, for example, an external dimension of length 1.6 mx width 0.4 mx thickness 150 mm.
  • Reference numeral 109 denotes a raw material gas temperature adjusting device, which is a gas for maintaining the temperature of a raw material gas described later, that is, a mixed gas of carrier gas and TTIP, by 10 to 30 ° C. higher than a set value of a TTIP temperature adjusting device 122a described later.
  • the temperature of the mixing box 105 and the first electrode 101 is maintained at 90 ° C.
  • first and second feeding points 110 a and 110 b are arranged on the first electrode 101.
  • the first and second feeding points 110a and 110b are connection points between a power supply system, which will be described later, and the first electrode 101, and power is supplied from these positions.
  • the first and second feeding points 110a and 110b are in a positional relationship facing each other, and are set at the ends of the electrodes and have a relationship as opposing points on the propagation of the high-frequency power wave.
  • Third and fourth feeding points 111 a and 111 b are arranged on the second electrode 103.
  • the third and fourth feeding points 111a and 111b are connection points between a power supply system described later and the electrode 103, and power is supplied from the positions.
  • the third and fourth feeding points 111a and 111b are in a positional relationship facing each other, and are set at the ends of the electrodes and have a relationship as opposing points in the propagation of the high-frequency power wave.
  • the distance between the first and second electrodes 101 and 103 can be arbitrarily set in advance when a substrate lifter 112 described later is operated up and down, and is set to a range of 5 mm to 40 mm, for example, 25 mm.
  • reference numeral 112 denotes a substrate lifter, which receives the substrate 108 on the second electrode 103 from a substrate carry-in / out gate 118 (not shown), up to a position where the distance between the first and second electrodes is maintained at a predetermined value.
  • the first and second electrodes 101 and 103 move to a position where the distance is 25 mm.
  • the vertical position of the substrate lifter 112 can be arbitrarily set, and the distance between the first and second electrodes is set in a range of 5 mm to 40 mm, for example.
  • a bellows 113 is used to keep the vacuum vessel 100 airtight when the substrate lifter 112 moves up and down.
  • connection conductor 115a and the third connection conductor 116a, and the second connection conductor 115b and the fourth connection conductor 116b have a spring characteristic so that they are pressed against each other when they are in contact with each other. is doing.
  • the first connection conductor 115a and the third connection conductor 116a, and the second connection conductor 115b and the fourth connection conductor 116b are set so as to ensure a conductive state with good reproducibility.
  • Reference numeral 108 denotes a substrate, which is disposed on the second electrode 103 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown). Then, it is heated to a predetermined temperature by a substrate heater 102 (not shown).
  • the substrate 108 is made of glass having a size of 1.5 mx 0.25 mx 4 mm in thickness.
  • the gas mixing box 105 is configured such that a mixed gas of carrier gas and TTIP supplied from a first source gas supply pipe 126 a to be described later via a source gas supply unit 132 passes through the gas shower hole 106. It has a function of supplying uniformly between the pair of electrodes 101 and 103.
  • the source gas supply unit 132 is made of an insulating material (not shown) and is electrically insulated. Further, it has a function of uniformly supplying oxygen gas supplied from a second source gas supply pipe 130 described later between the pair of electrodes 101 and 103 through the gas shower holes 107 and 106.
  • the second source gas supply pipe 130 is made of an insulating material (not shown) and is electrically insulated.
  • the supplied source gas such as TTIP and oxygen is turned into plasma between the pair of electrodes 101 and 103 and then discharged to the outside of the vacuum vessel 100 by the exhaust pipes 119a and 119b and a vacuum pump (not shown).
  • reference numeral 120a denotes TTIP, which is a raw material for the titanium oxide film.
  • Reference numeral 121a denotes a TTIP container, which is used in combination with a TTIP temperature adjusting device 122a described later.
  • Reference numeral 122a denotes a TTIP temperature adjusting device, which maintains the temperature of the TTIP container 121a at an arbitrary temperature in the range of 65 to 90 ° C, for example, 70 ° C. Then, a part of TTIP inside the container 121a is gasified. Further, when mixed with a carrier gas described later, the gas phase portion of the container 121a is saturated by the carrier gas and gasified TTIP.
  • Reference numeral 123a is a carrier gas supply source of TTIP, and for example, a cylinder such as hydrogen gas or argon gas is used.
  • Reference numeral 124a is a TTIP carrier gas flow meter, which can control a required gas flow rate.
  • Reference numeral 125a denotes a TTIP carrier gas supply pipe for supplying the carrier gas from the TTIP carrier gas supply source 123a to the TTIP container 121a.
  • Reference numeral 126 a is a titanium oxide source gas supply pipe, which supplies a mixed gas of TTIP gas and carrier gas generated in the TTIP container 121 a to the gas mixing box 105 via the source gas supply unit 132.
  • Reference numeral 131a denotes a gas flow rate adjusting device that can control the flow rate of the mixed gas of the TTIP gas and the carrier gas to a required flow rate.
  • the gas flow rate adjusting device 131a adjusts the flow rate of the carrier gas saturated with the generated organic metal as a result of bubbling the liquid organic metal in the container 121a with the carrier gas.
  • the pressure of the carrier gas flowing into the TTIP container 121a is set to 1 atm, for example, and is monitored by a pressure sensor (not shown).
  • the pressure of the carrier gas saturated with the organic metal flowing out of the TTIP container 121a is monitored by a pressure sensor (not shown).
  • Reference numeral 127a denotes a heater, which is 10 to 30 ° C. higher than the TTIP temperature adjusting device 122a, for example, 90 ° C. so that the mixed gas of the TTIP gas and the carrier gas flowing inside the titanium oxide source gas supply pipe 126a does not condense.
  • Reference numeral 133a denotes a flow path opening / closing valve.
  • the raw material gas flowing in the raw material gas supply pipe 126a is supplied to the gas mixing box 105 via the raw material gas supply unit 132 on the downstream side.
  • the flow path opening / closing valve 133a is closed, the source gas flowing inside the source gas supply pipe 126a is discharged toward an exhaust line (not shown).
  • the raw material (TTIP) 120a of the titanium oxide film the raw material (TTIP) 120a of the titanium oxide film, the TTIP container 121a, the TTIP temperature adjustment device 122a, the TTIP carrier gas supply source 123a, the TTIP carrier gas flow meter 124a, the gas flow rate adjustment device 131a, and the oxidation
  • a titanium oxide film material (TTIP) supply device An organometallic material supply device including the titanium source gas supply pipe 126a and the like is referred to as a titanium oxide film material (TTIP) supply device.
  • reference numeral 128 denotes an oxygen gas supply source, for example, an oxygen cylinder.
  • Reference numeral 129 is an oxygen gas flow meter which can control a required gas flow rate.
  • Reference numeral 130 denotes an oxygen gas supply pipe for supplying the gas from the oxygen gas supply source 128 to the gas mixing box 105.
  • the gas supply device including the oxygen gas supply source 128, the oxygen gas flow meter 129, and the oxygen gas supply pipe 130 is referred to as an oxygen gas supply device.
  • the pressure in the vacuum vessel 100 is monitored by a pressure gauge (not shown).
  • the pressure in the vacuum vessel 100 is adjusted by adjusting the flow meters 124a, 131a and 129 to a predetermined value, and by automatically adjusting the exhaust amount of a vacuum pump (not shown) to a predetermined value. Set to the required pressure.
  • the pressure is about 0.01 Torr to 10 Torr (1.33 Pa to 1330 Pa). Can be adjusted.
  • the vacuum ultimate pressure of the vacuum vessel 1 is about 2 to 3E-7 Torr (2.66 to 3.99E-5 Pa).
  • reference numeral 135 denotes a transmitter, which generates a sine wave signal of a high frequency band, for example, 13.56 MHz.
  • Reference numeral 136 denotes a signal distributor which branches the signal from the transmitter 136 into two.
  • Reference numeral 137 denotes a phase adjusting device that adjusts the phase of the sine wave signal. Note that the phase adjustment device 137 used here has a function capable of advancing or delaying the phase within a range of ⁇ 180 degrees, for example.
  • Reference numerals 138a and 138b respectively have a function of amplifying an input signal by the first and second power amplifiers. The output of this apparatus can be arbitrarily adjusted in the range of several hundred W to 10 KW.
  • W 11 (t) Asin ( ⁇ t + ⁇ 1 )
  • W 12 (t) Asin ( ⁇ t + ⁇ 2 )
  • A an amplitude
  • ⁇ an angular frequency
  • t time
  • ⁇ 1 and ⁇ 2 initial phases.
  • reference numerals 139a and 139b denote first and second matching units, respectively, and the outputs of the first and second amplifiers 138a and 138b are efficiently used for the plasma generated between the pair of electrodes 101 and 103. Adjust the output impedance to be transmitted. That is, the first matching device 139a adjusts the output impedance of the first amplifier 138a and the impedance of the plasma generated between the pair of electrodes 101 and 103 that are the loads. The second matching unit 139b adjusts and matches the output impedance of the second amplifier 138b and the impedance of the plasma generated between the pair of electrodes 101 and 103 serving as the load.
  • Reference numeral 140a denotes a first coaxial cable, together with a first connection conductor 115a and a third connection conductor 116a, through a first current introduction terminal 141a, a third coaxial cable 142a, and a first core wire 143a, which will be described later.
  • the output of the first amplifier 138a is supplied to the first and third feeding points 110a and 111a.
  • Reference numeral 141a denotes a first current introduction terminal attached to the wall of the vacuum vessel 100, which keeps the vacuum vessel airtight and connects the first coaxial cable 140a and the third coaxial cable 142a.
  • Reference numeral 140b denotes a second coaxial cable, together with a second connection conductor 115b and a fourth connection conductor 116b, through a second current introduction terminal 141b, a fourth coaxial cable 142b, and a second core wire 143b, which will be described later.
  • the output of the second amplifier 138b is supplied to the second and fourth feeding points 110b and 111b.
  • Reference numeral 141b denotes a second current introduction terminal attached to the wall of the vacuum vessel 100, which keeps the vacuum vessel airtight and connects the second coaxial cable 140b and the fourth coaxial cable 142b.
  • the first amplifier 138a is accompanied by a monitor of an output value (traveling wave) (not shown) and a monitor of a reflected wave that returns from the downstream side. Further, an isolator for protecting the electric circuit of the main body of the first power amplifier 138a by the reflected wave is attached.
  • the impedance is adjusted as follows. That is, the reactance (L and C) of the first matching unit 139a is adjusted while observing the traveling wave Pf and reflected wave Pr detectors attached to the first amplifier 138a. While adjusting the reactance (L and C) of the first matching unit 139a, a condition is selected in which the reflected wave Pr becomes the minimum value.
  • the output of the first amplifier 138a is set to a required value, and the reflected wave Pr becomes the minimum value while adjusting the reactance (L and C) of the first matching device 139a again with the output.
  • the adjustment of the matching unit that is, the condition under which the reflected wave Pr becomes the minimum value does not change unless the plasma generation condition is changed, and therefore does not require much time.
  • the function of the second amplifier 138b will be supplementarily described.
  • the second amplifier 138b is attached with a monitor of an output value (traveling wave) (not shown) and a monitor of a reflected wave that is reflected and returned from the downstream side. Further, an isolator for protecting the electric circuit of the second power amplifier 138b main body due to the reflected wave is attached.
  • the impedance is adjusted as follows. That is, the reactance (L and C) of the second matching unit 139b is adjusted while observing the traveling wave Pf and reflected wave Pr detectors attached to the second amplifier 138b. While adjusting the reactance (L and C) of the second matching unit 139b, a condition is selected in which the reflected wave Pr becomes a minimum value.
  • the output of the second amplifier 138b is set to a required value, and the reflected wave Pr becomes the minimum value while adjusting the reactance (L and C) of the second matching device 139b again with the output.
  • the adjustment of the matching unit that is, the condition under which the reflected wave Pr becomes the minimum value does not change unless the plasma generation condition is changed, and therefore does not require much time.
  • reference numeral 120b denotes a raw material for the zinc oxide film, for example, trimethyl zinc (CH 3 ) 3 Zn, triethyl zinc (C 2 H 5 ) 3 Zn, or diethyl zinc (C 2 H 5 ) 2 Zn. .
  • trimethyl zinc (CH 3 ) 3 Zn is used.
  • Reference numeral 121b denotes a raw material container for the zinc oxide film, which is used in combination with the raw material temperature control device 122b.
  • the temperature adjusting device 122b maintains the temperature of the container 121b at an arbitrary temperature in the range of 55 to 80 ° C., for example, 65 ° C.
  • Reference numeral 123b is a carrier gas supply source of the raw material for the zinc oxide film, and for example, a cylinder such as hydrogen gas or argon gas is used.
  • Reference numeral 124b is a carrier gas flow meter mixed in the raw material of the zinc oxide film, and the required gas flow rate can be controlled.
  • Reference numeral 125b denotes a carrier gas supply pipe for the raw material of the zinc oxide film, which supplies the carrier gas from the carrier gas supply source 123b to the raw material container 121b for the zinc oxide film.
  • Reference numeral 126b denotes a zinc oxide film raw material supply pipe, which supplies the mixed gas of the zinc oxide film raw material and the carrier gas generated in the container 121b to the gas mixing box 105 via the raw material gas supply unit 132.
  • Reference numeral 127b denotes a heater, which is 10 to 30 ° C. higher than the temperature adjustment device 122b so that the mixed gas of the zinc oxide film source gas and the carrier gas flowing inside the zinc oxide film source supply pipe 126b does not condense. Hold at 90 ° C.
  • Reference numeral 131b denotes a gas flow rate adjusting device that can control the flow rate of the mixed gas of the raw material gas of the zinc oxide film and the carrier gas to a required flow rate.
  • the pressure of the carrier gas flowing into the container 121b is set to 1 atm, for example, and is monitored by a pressure sensor (not shown).
  • the pressure of the carrier gas saturated with the organic metal flowing out from the container 121b is monitored by a pressure sensor (not shown).
  • a valve (not shown) installed in the carrier gas first supply pipe 125b and a control device (not shown) are automatically operated. Thus, backflow of the organic metal is prevented.
  • the zinc oxide film raw material 120b, the zinc oxide film raw material container 121b, the temperature adjusting device 122b, the zinc oxide film raw material carrier gas supply source 123b, and the zinc oxide film raw material carrier gas supply pipe 124b An organometallic material supply device including the gas flow rate adjusting device 131b and the zinc oxide film material supply pipe 126b is referred to as a zinc oxide film material supply device.
  • reference numeral 120c denotes a doping material for a zinc oxide film.
  • a doping material for a zinc oxide film For example, trimethylgallium (CH 3 ) 3 Ga, triethylgallium (C 2 H 5 ) 3 Ga, trimethylaluminum (CH 3 ) 3 Al, and triethylaluminum ( C 2 H 5 ) 3 Al.
  • trimethylgallium (CH 3 ) 3 Ga is used.
  • Reference numeral 121c denotes a container for the doping material, which is used in combination with the temperature adjusting device 122c for the material. The temperature adjusting device 122c maintains the temperature of the container 121c at an arbitrary temperature within the range of 60 to 90 ° C., for example, 70 ° C.
  • Reference numeral 123c denotes a carrier gas supply source of a doping material.
  • a carrier gas supply source for example, a cylinder such as hydrogen gas or argon gas is used.
  • Reference numeral 124c is a carrier gas flow meter, which can control a required gas flow rate.
  • Reference numeral 125c is a doping material carrier gas supply pipe for supplying the carrier gas from the carrier gas supply source 123c to the doping material container 121c.
  • Reference numeral 126c is a supply pipe for a mixed gas of a doping material and a carrier gas, and the mixed gas of an oxidizing doping material gas and a carrier gas generated in the container 121c.
  • the gas is supplied to the gas mixing box 105 via the source gas supply unit 132.
  • Reference numeral 127c is a heater, and is maintained at 10 to 30 ° C., for example, 90 ° C. higher than the temperature adjusting device 122c so that the mixed gas of the doping material gas and the carrier gas flowing inside the doping material gas supply pipe 126c does not condense.
  • Reference numeral 131c denotes a gas flow rate adjusting device that can control the flow rate of the mixed gas of the doping material gas and the carrier gas to a required flow rate.
  • the pressure of the carrier gas flowing into the container 121c is set to 1 atm, for example, and is monitored by a pressure sensor (not shown).
  • the pressure of the carrier gas saturated with the organic metal flowing out from the container 121c is monitored by a pressure sensor (not shown).
  • a valve (not shown) installed in the carrier gas first supply pipe 125c and a control device (not shown) are automatically operated. Thus, backflow of the organic metal is prevented.
  • An organometallic material supply device including the gas supply pipe 126c is referred to as a zinc oxide film doping material supply device.
  • Reference numeral 133b denotes a flow path opening / closing valve, and when opened, the organic metal source gas and doping gas flowing in the source gas supply pipes 126b and 126c are passed through the source gas supply unit 132 on the downstream side. Supply to the mixing box 105. When the flow path opening / closing valve 133b is closed, the organometallic source gas flowing in the source gas supply pipes 126b and 126c is discharged toward an exhaust line (not shown).
  • the pressure in the vacuum vessel 100 is monitored by a pressure gauge (not shown).
  • the pressure in the vacuum vessel 100 is adjusted to a predetermined value by adjusting the flow meters 124b, 131b, 124c, 131c, and 129, and the exhaust amount of a vacuum pump (not shown) is automatically set to a predetermined value. By adjusting, the required pressure is set.
  • the pressure is 0.01 Torr to 10 Torr (1. 33 Pa to 1330 Pa).
  • the vacuum ultimate pressure of the vacuum vessel 1 is about 2 to 3E-7 Torr (2.66 to 3.99E-5 Pa).
  • the method described here is a preliminary film formation test (preliminary production) required for grasping the film forming conditions of each of the amorphous titanium oxide film, the crystalline titanium oxide film, and the crystalline zinc oxide film and the film forming speed under those conditions.
  • glass having a size of 1.5 mx 0.25 mx 4 mm in thickness is previously placed on the second electrode 103 as a substrate 108 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown).
  • the substrate heater 102 sets the temperature of the substrate 108 in a range of 50 to 450 ° C., for example, 200 ° C.
  • the vacuum pump which is not illustrated is operated and the impurity gas etc. in the vacuum vessel 1 are removed.
  • the pressure in the vacuum vessel 100 is set in the range of 0.01 Torr to 1 Torr (1.33 Pa to 133 Pa), for example, 0.05 Torr (6.65 Pa) by the pressure adjusting device.
  • the temperature of the TTIP container 121a and the titanium oxide film material (TTIP) 120a is set to 70 to 90 ° C., for example, 70 ° C. by the temperature adjusting device 122a, and argon gas supplied from the TTIP carrier gas supply source 123a is used.
  • 400 sccm is set to 300 to 800 sccm with the flowmeter 124a of the carrier gas of TTIP.
  • the flow rate of the gas flow rate adjusting device 131a is set to 800 sccm. Then, in the TTIP container 121a, the TTIP raw material is bubbled with the argon gas as the carrier gas and vaporized. The vaporized mixed gas of TTIP raw material and argon gas is supplied to the flow path opening / closing valve 133a via the gas flow rate adjusting device 131a. Further, the temperature of the gas mixing box 105 and the first electrode 101 is previously set to 80 to 100 ° C., for example, 90 ° C. by the source gas temperature adjusting device 109.
  • the flow rate of the flow meter 129 of the oxygen gas supply device is set to 300 to 800 sccm, for example, 400 sccm. Then, oxygen at a flow rate of 400 sccm is supplied from the oxygen gas supply pipe 130 to the gas mixer 105.
  • a sine wave having a frequency of 13.56 MHz, for example, is generated from the transmitter 135, and the signal is divided into two by a distributor 136, one of which is a first power amplifier via a phase adjustment device 137.
  • the first and third feeding points 110a and 111a are amplified using the first impedance matching unit 139a, the first coaxial cable 140a, the first current introduction terminal 141a, the first core wire 143a, and the like.
  • the other signal is amplified by the second power amplifier 138b, and the second impedance matching unit 139b, the second coaxial cable 140b, the second current introduction terminal 141b, the second core wire 143b, and the like are used. 2 and the fourth feeding points 110b and 111b.
  • the outputs of the first and second power amplifiers 138a and 138b are set in the range of 0.5 to 2 kW, for example, 1.5 kW.
  • the intensity of the plasma between the pair of electrodes generated by the two supplied electric powers is proportional to the power intensity distribution shown below. That is, the power W 11 (t) expressed by the following equation is expressed between the first and third feeding points 110a and 111a, and is expressed by the following equation between the second and fourth feeding points 110b and 111b. Electric power W 12 (t) is supplied.
  • W 11 (t) Asin ( ⁇ t + ⁇ 1 )
  • W 12 (t) Asin ( ⁇ t + ⁇ 2 )
  • A an amplitude
  • ⁇ an angular frequency
  • t time
  • ⁇ 1 and ⁇ 2 are initial phases.
  • the power intensity between the pair of electrodes has a distribution of I (x, t) expressed by the following equation.
  • I (x, t) ⁇ cos 2 ⁇ 2 ⁇ (x ⁇ L0 / 2) / ⁇ / 2 ⁇
  • ⁇ is the wavelength of power
  • L0 the length of the electrode
  • ⁇ ⁇ 1 ⁇ 2 .
  • the reflected wave of the supplied power is prevented from returning to the upstream side of the respective impedance matching units 139a and 139b.
  • the flow path opening / closing valve 133a is opened.
  • the mixed gas of the carrier gas and the TTIP gas supplied from the upstream side is supplied to the gas mixing box 105 through the source gas supply unit 132.
  • a mixed gas of carrier gas and TTIP gas supplied from the titanium oxide film raw material (TTIP) supply device for example, 800 sccm
  • oxygen gas supplied from the oxygen gas supply device for example, 400 sccm
  • plasma of a mixed gas of carrier gas, TTIP gas, and oxygen is generated between the pair of electrodes 101 and 103.
  • the mixed gas of carrier gas, TTIP gas, and oxygen is plasmized, oxygen radicals and radicals including titanium are generated by plasma chemical reaction.
  • Various radicals in the plasma diffuse from a higher concentration to a lower concentration due to a diffusion phenomenon.
  • an amorphous titanium oxide film, a microcrystalline titanium oxide film, or a crystalline titanium oxide film is deposited on the glass substrate.
  • the substrate temperature is set to 10 to 30 minutes, for example, with the substrate temperature, the flow rate of the carrier gas, and the flow rate of oxygen gas as parameters. Then, a titanium oxide film is formed. After the film formation, the substrate 108 is taken out from the vacuum vessel 100, and the film quality and film thickness of the formed titanium oxide film are evaluated. For the evaluation of the film quality, laser Raman spectroscopy, scanning electron microscope (SEM), high resolution transmission electron microscope (TEM), secondary ion mass spectrometry (SIMS), or the like is used. The film thickness is measured with a scanning electron microscope (SEM), a step meter, or a spectroscopic ellipsometer.
  • SEM scanning electron microscope
  • TEM high resolution transmission electron microscope
  • SIMS secondary ion mass spectrometry
  • the substrate 108 is made of glass and the temperature of the substrate 108 is set in the range of 100 to 250 ° C., all films formed on the glass substrate 108 are non-coated.
  • the result is a crystalline titanium oxide. That is, the film forming speed depends on the high frequency power, the flow rate of the TTIP raw material, the flow rate of the carrier gas, and the pressure, but the film quality of the formed titanium oxide film is amorphous as shown in FIG. become.
  • the horizontal axis represents the film formation time
  • the vertical axis represents the film thickness and film quality, so that the titanium oxide film obtained when the substrate is glass and the substrate temperature is 100 to 250 ° C.
  • the film formation rate of amorphous titanium oxide is as follows under the above test conditions, that is, the flow rate of the mixed gas of the carrier gas and the TTIP raw material is 800 sccm, the flow rate of oxygen gas is 400 sccm, the pressure is 0.05 Torr (6.65 Pa), and the high frequency power is 1 In the case of .5 KW, about 10 nm / min is obtained.
  • the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
  • the film formed on the glass substrate 108 is As shown in FIG. 5, amorphous titanium oxide is used up to a film thickness of several tens of nm at the initial stage of film formation. Amorphous titanium oxide is amorphous over the amorphous titanium oxide in a film thickness of several tens of nm. Titanium oxide in a mixed phase of quality and microcrystal is formed. A crystalline titanium oxide film is formed on the mixed phase titanium oxide.
  • amorphous titanium oxide is used up to a film thickness of several tens of nm at the initial stage of film formation.
  • Amorphous titanium oxide is amorphous over the amorphous titanium oxide in a film thickness of several tens of nm. Titanium oxide in a mixed phase of quality and microcrystal is formed. A crystalline titanium oxide film is formed on the mixed phase titanium oxide.
  • the horizontal axis represents the film formation time and the vertical axis represents the film thickness and film quality, so that the titanium oxide film obtained when the substrate is glass and the substrate temperature is 250 to 380 ° C. as the film formation conditions.
  • the characteristics are shown.
  • the film formation rate of crystalline titanium oxide is as follows under the above test conditions, that is, a flow rate of 800 sccm of a mixed gas of carrier gas and TTIP raw material, a flow rate of 400 sccm of oxygen gas, a pressure of 0.05 Torr (6.65 Pa), and a high frequency power of 1. In the case of 5 KW, about 10 nm / min is obtained.
  • the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
  • the film formed on the glass substrate 108 As shown in FIG. 6, in the initial film thickness of 3 to 10 nm, a mixed phase of amorphous and microcrystalline titanium oxide is formed, on which crystalline titanium oxide is formed. Is formed.
  • the horizontal axis represents the film formation time and the vertical axis represents the film thickness and film quality, so that the titanium oxide film obtained when the substrate is glass and the substrate temperature is 380 to 450 ° C. as the film formation conditions. The characteristics are shown.
  • the film formation rate of crystalline titanium oxide is as follows under the above test conditions, that is, a flow rate of 800 sccm of a mixed gas of carrier gas and TTIP raw material, a flow rate of 400 sccm of oxygen gas, a pressure of 0.05 Torr (6.65 Pa), and a high frequency power of 1. In the case of 5 KW, about 20 nm / min is obtained. In addition, the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
  • the substrate 108 is made of glass, on which amorphous titanium oxide having a film thickness of several nm to 50 nm, or amorphous and microcrystalline 7 is formed by forming the mixed phase titanium oxide or crystalline titanium oxide, and setting the temperature condition of the substrate 108 in the range of 350 to 450 ° C. to form titanium oxide.
  • a crystalline titanium oxide film is obtained.
  • the horizontal axis indicates the film forming time
  • the vertical axis indicates the film thickness and film quality.
  • the base is an amorphous titanium oxide film, a microcrystalline titanium oxide film, or a crystalline oxide.
  • the characteristics of the titanium oxide film obtained when the substrate temperature is 350 to 450 ° C. with a titanium film are shown.
  • the film formation rate of crystalline titanium oxide is as follows under the above test conditions, that is, the flow rate of the mixed gas of the carrier gas and the TTIP raw material is 800 sccm, the flow rate of oxygen gas is 400 sccm, the pressure is 0.05 Torr (6.65 Pa), and the high-frequency power is 1 KW. In the case, about 20 nm / min is obtained.
  • the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
  • a glass substrate having a size of 1.5 mx 0.25 mx 4 mm in thickness, on which a crystalline titanium oxide film is formed on the surface of the substrate in advance, is used as a substrate 108 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown). And placed on the second electrode 103. Then, the temperature of the substrate 108 is set in the range of 200 to 450 ° C., for example, 300 ° C. by the substrate heater 102 (not shown). And the vacuum pump which is not illustrated is operated and the impurity gas etc. in the vacuum vessel 1 are removed. Further, the pressure in the vacuum vessel 100 is set in the range of 0.01 Torr to 1 Torr (1.33 Pa to 133 Pa), for example, 0.05 Torr (6.65 Pa) by the pressure adjusting device.
  • the flow path opening / closing valve 133b is closed in advance, and the mixed gas of the source gas and the doping gas supplied from the upstream zinc oxide film source supply device and the zinc oxide film doping material supply device is exhausted.
  • the temperature of the container 121b and the zinc oxide film material 120b of the zinc oxide film material supply apparatus is set to an arbitrary temperature in the range of 55 to 80 ° C., for example, 65 ° C.
  • the hydrogen gas supplied from the source 123b is set to 300 to 800 sccm, for example, 400 sccm by the carrier gas flow meter 124b.
  • the flow rate of the gas flow rate adjusting device 131b is set to 800 sccm. Then, in the container 121b, the zinc oxide raw material is bubbled by the carrier gas hydrogen gas and vaporized. The vaporized mixed gas of raw material and hydrogen gas is supplied to the flow path opening / closing valve 133b via the gas flow rate adjusting device 131b. Further, the temperature of the gas mixing box 105 and the first electrode 101 is previously set to 80 to 100 ° C., for example, 90 ° C. by the source gas temperature adjusting device 109.
  • the temperature of the container 121c and the doping material 120c of the doping material supply device for the zinc oxide film is set to an arbitrary temperature in the range of 60 to 90 ° C., for example, 80 ° C., in a state where the exhaust gas can be exhausted to the exhaust line.
  • the hydrogen gas supplied from the carrier gas supply source 123c is set to 20 to 80 sccm, for example, 35 sccm by the carrier gas flow meter 124c.
  • the flow rate of the gas flow rate adjusting device 131c is set to 70 sccm.
  • the doping material is bubbled by the hydrogen gas as the carrier gas and is vaporized.
  • the vaporized mixed gas of doping material and hydrogen gas is supplied to the flow path opening / closing valve 133b via the gas flow rate adjusting device 131c. Then, the flow rate of the flow meter 129 of the oxygen gas supply device is set to 300 to 800 sccm, for example, 400 sccm. Then, oxygen at a flow rate of 400 sccm is supplied from the oxygen gas supply pipe 130 to the gas mixer 105.
  • a sine wave having a frequency of 13.56 MHz, for example, is generated from the transmitter 135, and the signal is divided into two by a distributor 136, one of which is passed through a phase adjustment device 137.
  • the first and third power feedings are amplified by the first power amplifier 138a and using the first impedance matching unit 139a, the first coaxial cable 140a, the first current introduction terminal 141a, the first core wire 143a, and the like.
  • the points 110a and 111a are supplied.
  • the other signal is amplified by the second power amplifier 138b, and the second impedance matching unit 139b, the second coaxial cable 140b, the second current introduction terminal 141b, the second core wire 143b, and the like are used.
  • the outputs of the first and second power amplifiers 138a and 138b are set in the range of 0.5 to 2 kW, for example, 1.5 kW.
  • the intensity of the plasma between the pair of electrodes generated by the two supplied electric powers is proportional to the power intensity distribution shown below. That is, the power W 11 (t) expressed by the following equation is expressed between the first and third feeding points 110a and 111a, and is expressed by the following equation between the second and fourth feeding points 110b and 111b. Electric power W 12 (t) is supplied.
  • W 11 (t) Asin ( ⁇ t + ⁇ 1 )
  • W 12 (t) Asin ( ⁇ t + ⁇ 2 )
  • A an amplitude
  • ⁇ an angular frequency
  • t time
  • ⁇ 1 and ⁇ 2 are initial phases.
  • the power intensity between the pair of electrodes has a distribution of I (x, t) expressed by the following equation.
  • I (x, t) ⁇ cos 2 ⁇ 2 ⁇ (x ⁇ L0 / 2) / ⁇ / 2 ⁇
  • ⁇ is the wavelength of power
  • L0 the length of the electrode
  • ⁇ ⁇ 1 ⁇ 2 .
  • the reflected wave of the supplied power is prevented from returning to the upstream side of the respective impedance matching units 139a and 139b.
  • the flow path opening / closing valve 133b is opened. Then, the mixed gas of the carrier gas and the zinc oxide source gas supplied from the zinc oxide film source supply device is set to 800 sccm, for example.
  • the flow rates of the carrier gas and the doping gas supplied from the doping material supply device for the zinc oxide film are set to 70 sccm, for example.
  • the flow rate of the oxygen gas supplied from the oxygen gas supply device is set to 400 sccm, for example. As a result, the above flow rate, for example 1270 sccm, flows out from the gas shower 106 between the pair of electrodes 101 and 103.
  • plasma of a mixed gas of a carrier gas, a zinc oxide raw material, a doping material, and oxygen is generated between the pair of electrodes 101 and 103.
  • a mixed gas of a carrier gas, a zinc oxide raw material, a doping material, and oxygen is plasmized, various radicals including oxygen radicals and zinc radicals are generated by plasma chemical reaction.
  • Various radicals in the plasma diffuse from a higher concentration to a lower concentration due to a diffusion phenomenon.
  • a Ga-doped crystalline zinc oxide film is deposited on a glass substrate on which titanium oxide is formed as an underlayer.
  • the substrate 108 is taken out from the vacuum vessel 100, and the film quality and film thickness of the formed zinc oxide film are evaluated.
  • laser Raman spectroscopy, scanning electron microscope (SEM), high resolution transmission electron microscope (TEM), secondary ion mass spectrometry (SIMS), or the like is used.
  • Conductivity is measured using a conductivity meter.
  • a measuring instrument defined in JIS B0601 is used for the surface roughness.
  • the film thickness is measured with a scanning electron microscope (SEM), a step meter, or a spectroscopic ellipsometer.
  • the substrate 108 is a glass plate on which a titanium oxide film having a thickness of 20 nm or more is formed, and the temperature of the substrate 108 is set in a range of 200 to 400 ° C.
  • the film forming speed depends on the high-frequency power, the flow rate of the raw material, the flow rate of the carrier gas, and the pressure, but the film quality of the zinc oxide film to be formed becomes crystalline as shown in FIG. .
  • the horizontal axis indicates the film forming time
  • the vertical axis indicates the film thickness and film quality.
  • the base is a crystalline titanium oxide film and the substrate temperature is 200 to 400 ° C.
  • membrane obtained is shown. Further, the unevenness of the surface of the zinc oxide film to be formed is about 20 to 140 nm in terms of arithmetic average roughness defined by JIS B0601.
  • the film formation rate of the crystalline zinc oxide is the same as in the above test conditions, that is, the flow rate of the mixed gas of the carrier gas and the zinc oxide raw material is 800 sccm, the flow rate of the oxygen gas is 400 sccm, the flow rate of the mixed gas of the carrier gas and the doping gas is 70 sccm, and the pressure In the case of 0.05 Torr (6.65 Pa) and high frequency power of 1.5 kW, about 50 nm / min is obtained.
  • the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
  • the specific resistance of crystalline zinc oxide is 5 to 14 ⁇ 10 ⁇ 4 ⁇ ⁇ cm under the above test conditions. Note that the conductivity of the zinc oxide film depends on how the doping material is supplied, so it is necessary to optimize the conditions.
  • a film forming test (manufacturing process) of the thin film solar cell substrate 1a according to the first embodiment of the present invention will be described.
  • a thin film solar cell substrate 1a according to the first embodiment of the present invention shown in FIG. 1 is manufactured based on the result of the preliminary film forming test (preliminary film forming step). The procedure will be described below.
  • an amorphous titanium oxide layer 4a and a crystalline titanium oxide layer 4b are stacked on a glass substrate 2, and a crystalline oxide layer is formed on the crystalline titanium oxide layer 4b. It has a structure in which the zinc layer 5 is laminated.
  • the film thickness is set in the range of 10 to 50 nm, for example, 20 nm.
  • the crystalline titanium oxide layer 4b has a thickness in the range of 20 to 200 nm as an underlayer for providing an effect of promoting crystal growth of the crystalline zinc oxide 5 laminated on the film. For example, it is set to 100 nm.
  • the crystalline zinc oxide layer 5 has a characteristic necessary as a substrate for a thin film solar cell, that is, a film having an uneven structure, a high conductivity and a high light transmittance.
  • the thickness is set in the range of 200 to 2000 nm, for example, 800 nm. If the thickness is less than about 200 nm, the crystal grain size of the zinc oxide film to be formed is not sufficient. It may not be. On the other hand, when the film thickness exceeds about 2000 nm, the film forming time becomes longer and the cost is increased, and there is a problem that the light transmittance is lowered.
  • the amorphous titanium oxide layer 4a having a thickness of 20 nm is formed using a high-frequency plasma CVD apparatus for manufacturing a titanium oxide (TiO 2) film according to the first embodiment of the present invention shown in FIG. .
  • a high-frequency plasma CVD apparatus for manufacturing a titanium oxide (TiO 2) film according to the first embodiment of the present invention shown in FIG. .
  • the results of the preliminary film forming shown in FIGS. 4 and 6 are referred to.
  • a substrate 108 glass having a size of 1.5 mx 0.25 mx 4 mm in thickness is placed on the second electrode 103 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown).
  • the interval between the pair of electrodes 101 and 103 is set to 25 mm.
  • the substrate heater 102 sets the temperature of the substrate 108 in a range of 50 to 450 ° C., for example, 200 ° C.
  • the vacuum pump which is not illustrated is operated and the impurity gas etc. in the vacuum vessel 1 are removed.
  • the pressure in the vacuum vessel 100 is set to a range of 0.01 Torr to 1 Torr (1.33 Pa to 133 Pa), for example, 0.05 Torr (6.65 Pa) by the pressure adjusting device.
  • the amorphous titanium oxide layer 4a is formed in the same manner as in the case of forming the amorphous titanium oxide layer in the preliminary film forming test (preliminary film forming step).
  • the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm
  • the flow rate of the oxygen gas is set to 400 sccm
  • the high-frequency power is 1.5 kW.
  • the film formation time is 2 minutes.
  • the amorphous titanium oxide layer to be formed generally follows the characteristics shown in FIG.
  • the film forming speed in the preliminary film forming test is 10 nm / min
  • an amorphous titanium oxide layer 4 a having a film thickness of 20 nm is formed on the glass substrate 108.
  • the crystalline titanium oxide layer 4a is formed in the same manner as in the case of forming the crystalline titanium oxide layer in the preliminary film forming test (preliminary film forming step).
  • the substrate temperature is set to 390 ° C.
  • the flow rate of the mixed gas of the carrier gas and the TTIP material is set to 800 sccm
  • the flow rate of the oxygen gas is set to 400 sccm
  • the high frequency power is 1.5 kW.
  • the film forming time is 5 minutes.
  • the amorphous titanium oxide layer to be formed generally follows the characteristics shown in FIG.
  • the film-forming speed of the crystalline titanium oxide layer in the preliminary film-forming test is 20 nm / min, so that the upper surface of the amorphous titanium oxide layer 4a formed on the glass substrate 108 is Then, a crystalline titanium oxide layer 4b having a thickness of 100 nm is formed.
  • the crystalline zinc oxide layer 5 is formed in the same manner as in the case of forming the crystalline zinc oxide layer in the preliminary film forming test (preliminary film forming step).
  • the substrate temperature is set to 350 ° C.
  • the flow rate of the mixed gas of the carrier gas and the raw material is set to 800 sccm
  • the flow rate of the oxygen gas is set to 400 sccm
  • the flow rate of the mixed gas of the carrier gas and the doping material gas is set to 70 sccm. .5KW.
  • the film formation time is 16 minutes.
  • the formed crystalline zinc oxide layer generally follows the characteristics shown in FIG.
  • the film forming speed of the crystalline zinc oxide layer in the preliminary film forming test is 50 nm / min.
  • the amorphous titanium oxide layer 4a laminated on the glass substrate 108 and the crystalline A 800 nm-thick Ga-doped crystalline zinc oxide layer 5 is formed on the titanium oxide layer 4b.
  • the pressure in the vacuum vessel 100 is returned to atmospheric pressure, and an amorphous titanium oxide layer 4a, a crystalline titanium oxide layer 4b, and a Ga-doped crystalline zinc oxide are used using a substrate carry-in / out gate 118 (not shown).
  • the glass substrate 108 on which the layer 5 is laminated is taken out. As a result, a required thin film solar cell substrate 1a is obtained.
  • the substrate size of the first electrode 101 is 1.5 mx width 0.3 mx 20 mm in thickness
  • the substrate size is limited to the glass substrate of 1.5 mx 0.25 mx 4 mm in thickness.
  • the width of the substrate size can be increased by increasing the number of the pair of electrodes including the first and second electrodes 101 and 103.
  • the obtained thin film solar cell substrate 1a is an amorphous silicon solar cell or a tandem thin film solar cell (a thin film solar cell in which an amorphous silicon power generation layer and a microcrystalline silicon power generation layer are stacked in order from the light incident side). Applied. The application will be described below. In addition, the manufacturing method of an amorphous silicon solar cell or a tandem-type thin film solar cell is publicly known. In application to amorphous silicon solar cell production, as shown in FIG.
  • the thin film solar cell substrate 1 a that is, the amorphous titanium oxide layer 4 a sequentially laminated on the glass substrate 2, and crystalline titanium oxide
  • An amorphous p layer 6 having a film thickness of 7 to 15 nm, for example, 10 nm, and a film thickness are formed on a substrate composed of the layer 4b and the Ga-doped crystalline zinc oxide layer 5 by a plasma CVD method at a film forming temperature of 170 to 250 ° C.
  • An amorphous i layer 7 having a thickness of 150 to 400 nm, for example, 300 nm, and an amorphous n layer 8 having a thickness of 5 to 30 nm, for example, 20 nm are stacked.
  • a Ga-doped ZnO layer 9 having a film thickness of 10 to 100 nm, for example, 15 nm, and an Ag back electrode 10 having a film thickness of 100 to 300 nm, for example, 200 nm are laminated at a film formation temperature of 200 to 300 ° C. by sputtering.
  • a film formation temperature of 200 to 300 ° C. by sputtering.
  • the amorphous titanium oxide layer 4a sequentially laminated on the thin film solar cell substrate 1a, that is, the glass substrate 2, and the crystalline oxidation
  • An amorphous p layer 6 having a film thickness of 7 to 15 nm, for example, 10 nm, and a film are formed on a substrate composed of the titanium layer 4b and the Ga-doped crystalline zinc oxide layer 5 by a plasma CVD method at a film forming temperature of 170 to 250 ° C.
  • An amorphous i layer 7 having a thickness of 150 to 400 nm, for example, 300 nm, and an amorphous n layer 8 having a thickness of 5 to 30 nm, for example, 20 nm are stacked.
  • a microcrystalline n layer 14 having a thickness of 5 to 30 nm, for example, 20 nm is stacked.
  • a Ga-doped ZnO layer 9 having a film thickness of 20 to 100 nm, for example, 40 nm, and an Ag back electrode 10 having a film thickness of 100 to 300 nm, for example, 200 nm are stacked at a film forming temperature of 200 to 300 ° C. by sputtering.
  • a tandem-type thin film solar cell having a good performance with a stabilized power generation efficiency of 13 to 14.5%.
  • FIG. 11 is a structural diagram schematically showing a cross section of a thin-film solar cell substrate according to the second embodiment of the present invention.
  • reference numeral 2 denotes a translucent insulating substrate, for example, a glass substrate having a thickness of 4 to 5 mm.
  • Reference numeral 3b denotes a titanium oxide layer, which is an amorphous titanium oxide layer 4a and a titanium oxide film in which amorphous titanium oxide and crystalline titanium oxide are mixed (here, amorphous titanium oxide and crystalline titanium oxide). (Referred to as a mixed phase titanium oxide film) and a crystalline titanium oxide layer 4b.
  • Amorphous titanium oxide layer 4a, crystalline titanium oxide layer 4b, amorphous titanium oxide, and mixed phase titanium oxide 4c of crystalline titanium oxide are all formed by the above-described high-frequency plasma CVD apparatus shown in FIG. Is done.
  • Reference numeral 5 denotes a crystalline zinc oxide (ZnO) film layer. This crystalline zinc oxide (ZnO) film layer is formed by the above-described high-frequency plasma CVD apparatus shown in FIG. In addition, the crystalline zinc oxide (ZnO) film layer 5 may be formed by using a sputtering apparatus.
  • a thin film solar cell substrate 1b shown in FIG. 11 includes an amorphous titanium oxide layer 4a, a mixed phase titanium oxide 4c of amorphous titanium oxide and crystalline titanium oxide, and a crystalline titanium oxide layer on a glass substrate 2. 4b is laminated, and the crystalline zinc oxide layer 5 is laminated on the crystalline titanium oxide layer 4b.
  • the film thickness is set in the range of 10 to 50 nm, for example, 40 nm. To do. Further, the film thickness of the mixed phase titanium oxide 4c of amorphous titanium oxide and crystalline titanium oxide is utilized without being particularly controlled.
  • the crystalline titanium oxide layer 4b has a thickness in the range of 20 to 200 nm as an underlayer for providing an effect of promoting crystal growth of the crystalline zinc oxide 5 laminated on the film. For example, it is set to 100 nm.
  • the crystalline zinc oxide layer 5 has a characteristic necessary as a substrate for a thin film solar cell, that is, a film having an uneven structure, a high conductivity and a high light transmittance.
  • the thickness is set in the range of 200 to 2000 nm, for example, 800 nm. If the thickness is less than about 200 nm, the size of the crystal grains to be formed is not sufficient, and as a result, the surface roughness, which is one measure of the concavo-convex structure, does not fall within the arithmetic average roughness of 15 to 150 nm. is there. On the other hand, when the film thickness exceeds about 2000 nm, the film forming time becomes longer and the cost is increased, and there is a problem that the light transmittance is lowered.
  • the amorphous titanium oxide layer 4a having a thickness of 40 nm is formed using a high frequency plasma CVD apparatus for manufacturing a titanium oxide (TiO2) film shown in FIG. Regarding the film forming conditions, the results of the preliminary film forming shown in FIGS. 4 and 5 are referred to.
  • a substrate 108 glass having a size of 1.5 mx 0.25 mx 4 mm in thickness is placed on the second electrode 103 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown). In this case, the interval between the pair of electrodes 101 and 103 is set to 25 mm.
  • the substrate heater 102 sets the temperature of the substrate 108 in a range of 50 to 450 ° C., for example, 200 ° C.
  • the vacuum pump which is not illustrated is operated and the impurity gas etc. in the vacuum vessel 1 are removed.
  • the pressure in the vacuum vessel 100 is set to a range of 0.01 Torr to 1 Torr (1.33 Pa to 133 Pa), for example, 0.05 Torr (6.65 Pa) by the pressure adjusting device.
  • the amorphous titanium oxide layer 4a is formed in the same manner as in the case of forming the amorphous titanium oxide layer in the preliminary film forming test (preliminary film forming step).
  • the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm
  • the flow rate of the oxygen gas is set to 400 sccm
  • the high-frequency power is 1.5 kW.
  • the film formation time is 4 minutes.
  • the amorphous titanium oxide layer to be formed generally follows the characteristics shown in FIG.
  • the film forming speed in the preliminary film forming test is 10 nm / min
  • an amorphous titanium oxide layer 4 a having a film thickness of 40 nm is formed on the glass substrate 108.
  • the crystalline titanium oxide layer 4a is formed in the same manner as in the case of forming the crystalline titanium oxide layer in the preliminary film forming test (preliminary film forming step).
  • the substrate temperature is set to 350 ° C.
  • the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm
  • the flow rate of the oxygen gas is set to 400 sccm
  • the high frequency power is 1.5 kW.
  • the film formation time is 10 minutes.
  • the amorphous titanium oxide 4a and crystalline titanium oxide mixed phase titanium oxide 4c to be formed and the crystalline titanium oxide layer 4b generally follow the characteristics shown in FIG.
  • the film-forming speed of the crystalline titanium oxide layer 4b in the preliminary film-forming test is 10 nm / min, so that the amorphous titanium oxide layer 4a formed on the glass substrate 108 is formed.
  • a crystalline titanium oxide layer 3a having a thickness of 100 nm is formed thereon.
  • the crystalline zinc oxide layer 5 is formed in the same manner as in the case of forming the crystalline zinc oxide layer in the preliminary film forming test (preliminary film forming step).
  • the substrate temperature is set to 350 ° C.
  • the flow rate of the mixed gas of the carrier gas and the raw material is set to 800 sccm
  • the flow rate of the oxygen gas is set to 400 sccm
  • the flow rate of the mixed gas of the carrier gas and the doping material gas is set to 70 sccm. .5KW.
  • the film formation time is 16 minutes.
  • the amorphous titanium oxide layer to be formed generally follows the characteristics shown in FIG.
  • the film-forming speed of the crystalline zinc oxide layer in the preliminary film-forming test is 50 nm / min.
  • the amorphous titanium oxide layer 4a laminated on the glass substrate 108 and A 800 nm-thick Ga-doped crystalline zinc oxide layer 5 is formed on the crystalline titanium oxide and the mixed phase titanium oxide 4c of crystalline titanium oxide and the crystalline titanium oxide layer 4b.
  • the pressure in the vacuum vessel 100 is returned to atmospheric pressure, and an amorphous titanium oxide layer 4a and a mixed phase titanium oxide of amorphous titanium oxide and crystalline titanium oxide are used by using a substrate carry-in / out gate 118 (not shown).
  • the glass substrate 108 on which 4c, the crystalline titanium oxide layer 4b and the Ga-doped crystalline zinc oxide layer 5 are laminated is taken out. As a result, the required thin film solar cell substrate 1b is obtained.
  • the substrate temperature is set to 350 ° C.
  • the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm
  • the flow rate of the oxygen gas is set to 400 sccm
  • the high frequency power is 1.5 kW.
  • the film formation time is 10 minutes.
  • the mixed phase titanium oxide 4c of amorphous titanium oxide and crystalline titanium oxide to be formed and the crystalline titanium oxide layer 4b generally follow the characteristics shown in FIG.
  • an amorphous titanium oxide layer, a mixed phase of amorphous titanium oxide and crystalline titanium oxide, and crystalline titanium oxide are laminated in order from the glass substrate side.
  • the amorphous titanium oxide layer and two layers of a mixed phase of amorphous titanium oxide and crystalline titanium oxide are formed with a thickness of about 10 to 40 nm as a base on the glass substrate side. That is, when the film forming time is relatively long, most of the upper layer is a crystalline titanium oxide film.
  • the deposition rate of the crystalline titanium oxide film based on the mixed phase titanium oxide 4c of amorphous titanium oxide and crystalline titanium oxide formed on the amorphous titanium oxide layer is 10 nm / min. Therefore, if the film forming time is 10 minutes, the film thickness is 100 nm.
  • a thin film solar cell substrate according to the second embodiment of the present invention is obtained by forming a zinc oxide film on the crystalline titanium oxide film having a thickness of 100 nm.
  • the substrate size of the first electrode 101 is 1.5 mx width 0.3 mx 20 mm in thickness
  • the substrate size is limited to the glass substrate of 1.5 mx 0.25 mx 4 mm in thickness.
  • the width of the substrate size can be increased by increasing the number of the pair of electrodes including the first and second electrodes 101 and 103.
  • FIG. 2 a thin film solar cell substrate and a method for manufacturing the same according to a third embodiment of the present invention will be described with reference to FIG. Reference is also made to FIG. 2, FIG. 3 and FIG.
  • FIG. 12 is a structural view schematically showing a cross section of a thin film solar cell substrate according to the third embodiment of the present invention.
  • reference numeral 2 denotes a translucent insulating substrate, for example, a glass substrate having a thickness of 4 to 5 mm.
  • Reference numeral 3c denotes a titanium oxide layer, which is a titanium oxide film in which amorphous titanium oxide and crystalline titanium oxide are mixed (referred to herein as a mixed phase titanium oxide film of amorphous titanium oxide and crystalline titanium oxide). 4c and a crystalline titanium oxide layer 4b.
  • the mixed phase titanium oxide 4c and the crystalline titanium oxide layer 4b of amorphous titanium oxide and crystalline titanium oxide are both formed by the above-described high-frequency plasma CVD apparatus shown in FIG.
  • Reference numeral 5 denotes a crystalline zinc oxide (ZnO) film layer.
  • This crystalline zinc oxide (ZnO) film layer is formed by the above-described high-frequency plasma CVD apparatus shown in FIG.
  • the crystalline zinc oxide (ZnO) film layer 5 may be formed by using a sputtering apparatus.
  • the substrate temperature is set to 390 ° C.
  • the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm
  • the flow rate of the oxygen gas is set to 400 sccm
  • the high frequency power is 1.5 kW.
  • the film forming time is 5 minutes.
  • the mixed phase titanium oxide layer of amorphous titanium oxide and crystalline titanium oxide and the crystalline titanium oxide layer to be formed generally follow the characteristics shown in FIG. In the structure of the titanium oxide film shown in FIG.
  • a mixed phase titanium oxide layer 4c of amorphous titanium oxide and crystalline titanium oxide and a crystalline titanium oxide 4b are laminated in order from the glass substrate side.
  • the mixed phase titanium oxide layer 4c of amorphous titanium oxide and crystalline titanium oxide is formed with a thickness of about 20 to 40 nm as a base on the glass substrate side. That is, when the film formation time is relatively long, most of the upper layer is the crystalline titanium oxide film 4b. Since the deposition rate of the crystalline titanium oxide film having the mixed phase titanium oxide layer 4c of the amorphous titanium oxide and the crystalline titanium oxide as a base is 20 nm / min, if the deposition time is 5 minutes, The film thickness is 100 nm.
  • a thin film solar cell substrate according to the third embodiment of the present invention is obtained by forming a zinc oxide film 5 on the crystalline titanium oxide film 4b having a thickness of 100 nm.
  • a separate SiO 2 film having a thickness of about 20 to 100 nm is formed between the glass 2 and the mixed phase titanium oxide layer 4c of amorphous titanium oxide and crystalline titanium oxide. It is also possible to form a barrier layer of alkali components and moisture by forming a film.
  • the amorphous titanium oxide and the crystalline titanium oxide are formed on the light transmissive insulating substrate.
  • a substrate for a thin film solar cell in which crystalline zinc oxide having a large crystal grain size doped with Ga or Al is laminated.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Photovoltaic Devices (AREA)
  • Physical Vapour Deposition (AREA)
  • Chemical Vapour Deposition (AREA)

Abstract

In order to provide a substrate for thin film solar cell which is inexpensive and excellent in electrical and optical performance in comparison to a conventional substrate for thin film solar cell (transparent electrode), a substrate for thin film solar cell of a novel structure and a device and method relating to manufacture thereof are provided. A high-frequency plasma CVD device made from an organic metallic material laminates a transparent electrode film consisting of a three-layer structure of an amorphous titanium oxide film, a crystalline titanium oxide film, and a crystalline zinc oxide film on a transparent insulation substrate. This makes it possible to manufacture the substrate for thin film solar cell which is inexpensive, has an optical confinement effect (the relief structure of a film), and is highly conductive and highly light-transmissive.

Description

薄膜太陽電池用基板及びその製造方法、並びにそれを用いた薄膜太陽電池Thin film solar cell substrate, method for producing the same, and thin film solar cell using the same
　本発明は、薄膜太陽電池用基板及びその製造方法、並びにそれを用いた薄膜太陽電池に関する。 The present invention relates to a thin film solar cell substrate, a method for producing the same, and a thin film solar cell using the same.
　アモルファスシリコン太陽電池及びタンデム型薄膜シリコン太陽電池（アモルファスシリコンセルと微結晶シリコンセルを組み合わせたもの）等の薄膜太陽電池に用いられる透明電極には、高い導電性を有するこという電気的特性、及び高い透明性と光閉じ込め効果（膜の凹凸構造）を有するこという光学的特性が求められる。更に、プラズマにさらされた場合に変色しないこと、即ち、耐プラズマ特性が優れていることが求められる。
　耐プラズマ特性が低い場合は、例えば、薄膜シリコン太陽電池用の光電変換層がプラズマＣＶＤ法で製造される際に、透明電極の膜面がプラズマにより還元されて黒く変質する。その結果、黒化した部分で入射光が吸収されて、光電変換層への光入射量が低減し、発電効率が低下するという問題が発生する。
　上記ニーズに対応する為に、従来は、例えば、特許文献１（特開２００３－８１６３３）に記載されている熱ＣＶＤ法で製造される酸化錫（ＳｎＯ２）を主成分とする透明電極が採用されている。
　しかしながら、この酸化錫（ＳｎＯ２）を主成分とする透明電極は、耐プラズマ特性が充分に高くないために、該透明電極の表面に酸化亜鉛（ＺｎＯ）をコーテイングすることなどの対策が必要である。それ故、上記コーテイングが必要であるということは、後述の酸化亜鉛（ＺｎＯ）で形成された透明電極を用いる場合に比べて、製造コストが増大するという問題を抱えている。
　また、熱ＣＶＤ法は、酸化錫（ＳｎＯ２）を主成分とする透明電極を製造するのに、５５０～６５０℃という高温プロセスが必要である。そのため、基板に強化ガラスを使う場合、強化ガラスはその高温プロセスにより強化が取れて、通常ガラスに変質する。したがって、強化ガラスを基板に使うことが出来ず、大面積ガラス基板を用いる場合、ガラス基板の強度を確保するために、ガラス厚みを増大（重量増大）させる必要がある。その結果、基板に強化ガラスを使う場合に比べて、重量が４～５倍も増大し、使い勝手が悪いのみならず、製造コストが増大するという問題を抱えている。 Transparent electrodes used in thin film solar cells such as amorphous silicon solar cells and tandem thin film silicon solar cells (a combination of amorphous silicon cells and microcrystalline silicon cells) have electrical properties that have high conductivity, and Optical characteristics are required to have high transparency and light confinement effect (uneven structure of the film). Furthermore, it is required not to change color when exposed to plasma, that is, to have excellent plasma resistance.
In the case where the plasma resistance is low, for example, when a photoelectric conversion layer for a thin film silicon solar cell is manufactured by a plasma CVD method, the film surface of the transparent electrode is reduced by the plasma and changed to black. As a result, the incident light is absorbed in the blackened portion, the amount of light incident on the photoelectric conversion layer is reduced, and power generation efficiency is reduced.
In order to meet the above needs, conventionally, for example, a transparent electrode mainly composed of tin oxide (SnO 2) manufactured by a thermal CVD method described in Patent Document 1 (Japanese Patent Laid-Open No. 2003-81633) has been adopted. ing.
However, since the transparent electrode mainly composed of tin oxide (SnO2) does not have sufficiently high plasma resistance, it is necessary to take measures such as coating zinc oxide (ZnO) on the surface of the transparent electrode. . Therefore, the necessity of the above-mentioned coating has a problem that the manufacturing cost increases as compared with the case where a transparent electrode formed of zinc oxide (ZnO) described later is used.
In addition, the thermal CVD method requires a high-temperature process of 550 to 650 ° C. to manufacture a transparent electrode mainly composed of tin oxide (SnO 2). Therefore, when tempered glass is used for the substrate, the tempered glass is tempered by the high temperature process, and is usually transformed into glass. Therefore, when tempered glass cannot be used for a substrate and a large area glass substrate is used, it is necessary to increase the glass thickness (weight increase) in order to ensure the strength of the glass substrate. As a result, the weight increases by 4 to 5 times compared to the case where tempered glass is used for the substrate, which is not only inconvenient but also increases in manufacturing cost.
　他方、上記の問題を改善する試みとして、新しい構造の透明電極層、及びその製造方法が、例えば、特許文献２（特許第３２１５１２８号）、特許文献３（特開２０００－１５０９２８）、特許文献４（特開２００５－３１１２９２）及び特許文献５（特開２００１－０１５７８７）に記載されている。 On the other hand, as an attempt to improve the above problems, a transparent electrode layer having a new structure and a method for producing the same are disclosed in, for example, Patent Document 2 (Patent No. 3215128), Patent Document 3 (Japanese Patent Laid-Open No. 2000-150928), and Patent Document 4 (Japanese Unexamined Patent Application Publication No. 2005-311292) and Japanese Patent Application Laid-Open No. 2001-015787.
　特許文献２（特許第３２１５１２８号）には、スパッタ法により、酸化亜鉛（ＺｎＯ）を主成分とする透明電極を製造する方法が記載されている。この方法は、ＡｌをドープしたＺｎＯターゲットを用い、スパッタガス圧を２Ｐａ以上、基板温度を２５０℃以上としてスパッタリングを行うことを特徴とする。また、この方法で製造される酸化亜鉛（ＺｎＯ）を主成分とする透明電極は、０．１～１０μｍの大きさをもつカラム状または粒状の粒塊が膜表面に０．１～１０μｍの空隙を形成して充填され、膜の光透過率が光入射角に依存する、ＡｌをドープされたＺｎＯ薄膜であることを特徴とする。
　しかしながら、このスパッタ法で製造される透明電極膜は、上記のように、０．１～１０μｍの大きさをもつカラム状または粒状の粒塊が膜表面に０．１～１０μｍの空隙を形成して充填されることから、薄膜シリコン太陽電池用の透明電極には不向きである。即ち、上記空隙を有する透明電極膜の上に光電変換層を構成するｐ型半導体膜（厚みは、例えば、５～２０ｎｍ）を製膜する場合、上記透明電極膜表面にある空隙部分には上記ｐ型半導体膜は形成されない。また、得られるｐ型半導体膜の品質は、その空隙部分の構造に影響される。その結果、上記透明電極膜表面に製膜されるｐ型半導体膜を高品質に、かつ、再現性良く製造することが困難であるという問題がある。 Patent Document 2 (Japanese Patent No. 3215128) describes a method for producing a transparent electrode containing zinc oxide (ZnO) as a main component by sputtering. This method is characterized in that sputtering is performed using a ZnO target doped with Al at a sputtering gas pressure of 2 Pa or more and a substrate temperature of 250 ° C. or more. In addition, the transparent electrode mainly composed of zinc oxide (ZnO) produced by this method has a columnar or granular agglomerate having a size of 0.1 to 10 μm and a void of 0.1 to 10 μm on the film surface. A ZnO thin film doped with Al, in which the light transmittance of the film depends on the light incident angle.
However, in the transparent electrode film manufactured by this sputtering method, as described above, columnar or granular agglomerates having a size of 0.1 to 10 μm form voids of 0.1 to 10 μm on the film surface. Therefore, it is not suitable for a transparent electrode for a thin film silicon solar cell. That is, when a p-type semiconductor film (thickness is, for example, 5 to 20 nm) constituting a photoelectric conversion layer is formed on the transparent electrode film having the voids, A p-type semiconductor film is not formed. Further, the quality of the obtained p-type semiconductor film is affected by the structure of the void portion. As a result, there is a problem that it is difficult to manufacture a p-type semiconductor film formed on the surface of the transparent electrode film with high quality and good reproducibility.
　特許文献３（特開２０００－１５０９２８）には、透光性基板上に、スパッタリング法にてアルミニウム膜を形成し、そのアルミニウム膜を部分的にエッチング除去して、その表面を凹凸化し、大気中または窒素雰囲気中での加熱により、該アルミニウム膜を酸化または窒化させて、結晶化された酸化アルミニウムまたは窒化アルミニウムのアルミニウム化合物膜に変化させ、スパッタリング法にて、酸化亜鉛または酸化錫からなる透明導電性膜を形成して、透明電極基板を製作する方法が記載されている。
　この方法は、次に示す特徴を有する。即ち、スパッタリング法にて透明導電性膜を透光性基板に形成してなる透明電極基板において、前記透光性基板と前記透明導電性膜との間に、凹凸化したアルミニウム化合物膜を備えることを特徴とする。また、スパッタリング法にて透明導電性膜を透光性基板に形成してなる透明電極基板を作成する方法において、前記透光性基板にアルミニウム膜を形成する工程と、形成したアルミニウム膜をエッチングして凹凸化する工程と、アルミニウム膜をアルミニウム化合物膜に変化させる工程と、アルミニウム化合物膜にスパッタリング法にて透明導電性膜を形成する工程とを有することを特徴とする。
　しかしながら、この方法は、製造プロセスが４つの工程、即ち、前記透光性基板にアルミニウム膜を形成する工程と、形成したアルミニウム膜をエッチングして凹凸化する工程と、アルミニウム膜をアルミニウム化合物膜に変化させる工程と、アルミニウム化合物膜にスパッタリング法にて透明導電性膜を形成する工程とから成り、複雑である。
　このことは、実用の生産ラインに応用される場合、製造プロセスを構成する装置の導入費用が増大すること、及びランニングコストが増大することなどを意味している。また、一般的に、製造プロセスが多くなればなるほど、製品の歩留まりは低下することが知られており、その結果、生産コストの増大の原因を抱えているという問題がある。 In Patent Document 3 (Japanese Patent Application Laid-Open No. 2000-150928), an aluminum film is formed on a light-transmitting substrate by a sputtering method, the aluminum film is partially etched away, and the surface thereof is roughened. Alternatively, the aluminum film is oxidized or nitrided by heating in a nitrogen atmosphere to change into a crystallized aluminum oxide or aluminum nitride aluminum compound film, and transparent conductive material made of zinc oxide or tin oxide is formed by sputtering. A method for forming a transparent electrode substrate by forming a conductive film is described.
This method has the following characteristics. That is, in a transparent electrode substrate formed by forming a transparent conductive film on a light-transmitting substrate by a sputtering method, an uneven aluminum compound film is provided between the light-transmitting substrate and the transparent conductive film. It is characterized by. Further, in a method of forming a transparent electrode substrate formed by forming a transparent conductive film on a light-transmitting substrate by a sputtering method, a step of forming an aluminum film on the light-transmitting substrate, and etching the formed aluminum film And a step of changing the aluminum film into an aluminum compound film, and a step of forming a transparent conductive film on the aluminum compound film by a sputtering method.
However, in this method, the manufacturing process has four steps, that is, the step of forming an aluminum film on the translucent substrate, the step of etching the formed aluminum film to make it uneven, and the aluminum film as an aluminum compound film. The process is complicated and includes a process of forming a transparent conductive film on the aluminum compound film by sputtering.
This means that when applied to a practical production line, the introduction cost of the apparatus constituting the manufacturing process increases and the running cost increases. In general, it is known that as the number of manufacturing processes increases, the yield of products decreases. As a result, there is a problem that the cause of the increase in production cost is held.
　特許文献４（特開２００５－３１１２９２）には、低圧熱ＣＶＤ法（あるいは、ＭＯＣＶＤ法と呼ばれる方法、Ｍｅｔａｌ－Ｏｒｇａｎｉｃ　Ｃｈｅｍｉｃａｌ　Ｖａｐｏｒ　Ｄｅｐｏｓｉｔｉｏｎ）を用いる方法が記載されている。この方法は、ガラス基板上に、予め、透光性微粒子（シリカ：ＳｉＯ２、酸化チタン：ＴｉＯ２、酸化アルミニウム：Ａｌ２Ｏ３、酸化ジルコニウム：ＺｒＯ２、酸化インジウム錫：ＩＴＯ、またはフッ化マグネシウム：ＭｇＦ２など）を塗布し、その透光性微粒子の上に、低圧熱ＣＶＤ法によりＺｎＯ膜を形成させるものである。
　この方法は、次に示すような特徴を有する。即ち、透光性絶縁基板、及び該透光性絶縁基板上に堆積された少なくとも酸化亜鉛を含む透明電極層からなる薄膜太陽電池用基板であって、該透光性絶縁基板は該透明電極層側の界面に二乗平均平方根粗さが５～５０ｎｍである微細な表面凹凸を有し、その凸部は局面からなることを特徴とする。
　また、前記透明電極層は１μｍ以上の膜厚を有することを特徴とする。
　また、前記透光性絶縁基板は平滑な表面を有する透光性基体と透光性下地層との積層体からなり、該透光性下地層は、平均粒径が１０ｎｍ以上で１００ｎｍ未満の透光性微粒子と、透光性バインダーとを含むことを特徴とする。
　また、前記透光性絶縁基板の温度が１５０℃以上で、前記少なくとも酸化亜鉛を含む透明電極層を堆積することを特徴とする。
　なお、実施例として示されている上記特徴を有する薄膜太陽電池用基板は、ガラス基板の上に、透光性バインダーと透光性微粒子からなる透光性下地層が配置され、該透光性下地層の上に透明電極層が積層されるという構造を有する。
　しかしながら、この方法は、透光性絶縁基板の上に、溶媒を含んだ透光性バインダー（シリコン酸化物、アルミニウム酸化物、チタン酸化物、及びジルコニウム酸化物など）と透光性微粒子とを、デイッピング法、スピンコート法、あるいはスプレー法等で塗布し、塗布操作が完了した後に、直ちに塗布薄膜を加熱乾燥させるという工程が必要である。その結果、溶媒を含んだ透光性バインダーと透光性微粒子から成る透光性下地層と、透光性基体との接着力は充分に強固であるのかどうかという問題と、高温度（１５０℃以上）にさらされた場合に該接着力が低下しないかどうかという問題等を抱えている。更には、長期的安定性が良好かどうかという問題を抱えている。
　また、上記塗布薄膜の加熱乾燥工程において、溶媒を含んだ透光性バインダーと透光性微粒子の中から溶媒が抜けると、その溶媒があった部分には空隙ができて、一般的にはポーラスな状態になる。このポーラスな状態は、プラズマＣＶＤ法による発電膜の製造工程において、不純物発生源となる。その結果、発電効率の高い太陽電池の製造が困難になるという問題の発生も考えられる。 Patent Document 4 (Japanese Patent Laid-Open No. 2005-311292) describes a method using a low-pressure thermal CVD method (or a method called MOCVD method, Metal-Organic Chemical Vapor Deposition). In this method, light-transmitting fine particles (silica: SiO2, titanium oxide: TiO2, aluminum oxide: Al2O3, zirconium oxide: ZrO2, indium tin oxide: ITO, or magnesium fluoride: MgF2) are preliminarily formed on a glass substrate. The ZnO film is formed on the light-transmitting fine particles by low-pressure thermal CVD.
This method has the following characteristics. That is, a thin film solar cell substrate comprising a light-transmitting insulating substrate and a transparent electrode layer containing at least zinc oxide deposited on the light-transmitting insulating substrate, the light-transmitting insulating substrate being the transparent electrode layer The side interface has fine surface irregularities having a root mean square roughness of 5 to 50 nm, and the convex portions are composed of phases.
The transparent electrode layer has a thickness of 1 μm or more.
The translucent insulating substrate is a laminate of a translucent substrate having a smooth surface and a translucent underlayer, and the translucent underlayer has an average particle diameter of 10 nm or more and less than 100 nm. It contains a light-sensitive fine particle and a light-transmitting binder.
Further, the transparent insulating substrate is deposited at a temperature of 150 ° C. or more and containing at least zinc oxide.
In the thin film solar cell substrate having the above-described characteristics shown as an example, a translucent underlayer composed of a translucent binder and translucent fine particles is disposed on a glass substrate, and the translucent layer A transparent electrode layer is laminated on the base layer.
However, in this method, a translucent binder containing a solvent (such as silicon oxide, aluminum oxide, titanium oxide, and zirconium oxide) and translucent fine particles are formed on a translucent insulating substrate. It is necessary to apply a dipping method, a spin coating method, a spray method, or the like and immediately dry the coated thin film after the coating operation is completed. As a result, the problem of whether the adhesive force between the translucent underlayer composed of a translucent binder containing a solvent and translucent fine particles and the translucent substrate is sufficiently strong, and high temperature (150 ° C. And the like) whether the adhesive strength does not decrease when exposed to the above. Furthermore, there is a problem of whether long-term stability is good.
In addition, when the solvent is removed from the translucent binder containing the solvent and the translucent fine particles in the heating and drying step of the coated thin film, voids are formed in the portion where the solvent is present, and the porous film is generally porous. It becomes a state. This porous state becomes an impurity generation source in the manufacturing process of the power generation film by the plasma CVD method. As a result, there may be a problem that it is difficult to manufacture a solar cell with high power generation efficiency.
　特許文献５（特開２００１－０１５７８７）には、スパッタ法により高速で製膜でき生産性に富む、表面凹凸構造を有する透明導電膜付き基体と製造方法及び該透明導電膜付き基体を用いてなる太陽電池が記載されている。
　この方法は、スパッタ法により基体上に酸化チタンと酸化亜鉛を積層することがアイデイアのポイントであり、次に示すような特徴を有する。即ち、基体上に形成された酸化チタンを主成分とする膜の上に接して酸化亜鉛を主成分とする透明導電膜を積層する透明導電膜付き基体の製造方法であることを特徴とする。
　また、基体上に形成された酸化チタンを主成分とする膜の上に接して酸化亜鉛を主成分とする透明導電膜が積層された透明導電膜付き基体であることを特徴とする。
　また、該透明導電膜付き基体の酸化亜鉛を主成分とする透明導電膜の上に、光電変換層と、電極層がこの順に形成された太陽電池であることを特徴とする。
　また、上記特許文献５に記載の透明導電膜付き基体は、例えば、次のようにして作成される。即ち、ガラス基板上に、Ｔｉターゲットを用いて、酸化反応性スパッタ法でＴｉＯ２膜を０．５～２００ｎｍの膜厚で形成し、次いで、酸化亜鉛を主成分とする導電性の酸化物ターゲットを用いて、アルゴンガス中でスパッタして、酸化亜鉛系透明導電膜を前記ＴｉＯ２膜に接して製膜することにより作製される。 Patent Document 5 (Japanese Patent Laid-Open No. 2001-015787) uses a substrate with a transparent conductive film having a surface uneven structure, which can be formed at high speed by a sputtering method, and has high productivity, and a manufacturing method, and the substrate with a transparent conductive film. A solar cell is described.
In this method, the point of idea is that titanium oxide and zinc oxide are laminated on a substrate by sputtering, and has the following characteristics. That is, it is a method for producing a substrate with a transparent conductive film in which a transparent conductive film mainly composed of zinc oxide is laminated on a film mainly composed of titanium oxide formed on the substrate.
Further, the present invention is characterized in that it is a substrate with a transparent conductive film in which a transparent conductive film mainly composed of zinc oxide is laminated in contact with a film mainly composed of titanium oxide formed on the substrate.
Moreover, it is a solar cell in which a photoelectric conversion layer and an electrode layer are formed in this order on a transparent conductive film containing zinc oxide as a main component of the substrate with the transparent conductive film.
Moreover, the base | substrate with a transparent conductive film of the said patent document 5 is produced as follows, for example. That is, a TiO2 film having a thickness of 0.5 to 200 nm is formed on a glass substrate by an oxidation reactive sputtering method using a Ti target, and then a conductive oxide target mainly composed of zinc oxide is formed. The zinc oxide transparent conductive film is formed in contact with the TiO 2 film by sputtering in argon gas.
　更に、特許文献５（特開２００１－０１５７８７）には、概略以下のことが示されている。
　（ａ）酸化チタン膜については、変換効率が高い太陽電池を得る観点から、光の透過性が高い透明膜であることとし、例えば、ＴｉＯ２膜や、ＴｉＯ２膜に別の成分（例えば、ＳｉＯ２、Ａｌ２Ｏ３、Ｆｅ２Ｏ３）をドープした膜を挙げている。その膜厚は、０．５～２００ｎｍ、特には１～１０ｎｍが好ましい。また、酸化チタン膜の形態としては、連続膜、不連続膜のいずれでも良い。
　酸化チタン膜を製膜するための酸化物ターゲットには、ＴｉＯ２、あるいはＴｉＯ２－ｘを用いるが、ＴｉＯ２の場合は導電性がないので、高周波（ＲＦ）スパッタ法にかぎられ、ＴｉＯ２－ｘの場合は導電性があるので直流スパッタ法あるいは高周波（ＲＦ）スパッタ法のいずれでも良い。
　スパッタ法で酸化チタン膜を製膜する際の基板温度は、０～６００℃が好ましい。また、特には、２０～４００℃が好ましい。
　（ｂ）酸化亜鉛膜については、表面凹凸状態が、ＪＩＳ　Ｂ０６０１で定義される算術平均粗さが１５～１５０ｎｍであることが好ましい。１５ｎｍより小さいと、光閉じ込め効果が低くなる傾向にあり、１５０ｎｍより大きいと粗すぎて、膜上に形成される光電変換層の膜厚が不均一になり、あるいは、光電変換層が形成されない部分が生じ、その結果、発電効率が低下する傾向にある。
　また、酸化亜鉛系透明導電膜としては、ＺｎＯに別の成分（例えば、Ｂ、Ａｌ、Ｇａ、Ｉｎ、Ｓｉ及びＴｉからなる群からえらばれる１種以上）をドーパントとしてドープした膜が挙げられている。特に、ＡｌあるいはＧａが好ましい。なお、ドーパントの含有割合は、ドーパントの総量と亜鉛（ＺｎＯ）との合計に対するドーパントの総量が、０．０１～１０原子％であることが好ましい。
　また、酸化亜鉛系透明導電膜の膜厚は、１００～３０００ｎｍが好ましい。特には、１００～１０００ｎｍが好ましい。１００ｎｍより薄いと、凹凸構造が現れにくい。また、３０００ｎｍより厚いと、製膜に時間が掛かり実用的でなく、かつ、光の吸収量が増えて、光エネルギーを多く損失する。また、酸化亜鉛系透明導電膜の形態としては、連続膜（電子顕微鏡で見て、明らかに連続的と思われる程度の膜厚を有する膜）であることが好ましい。
　酸化亜鉛系透明導電膜を製膜する際の基板温度は、０～６００℃が好ましい。また、特には、２０～４００℃が好ましい。
　また、酸化亜鉛系透明導電膜のスパッタ製膜時のスパッタ圧は、特に限定されず、一般に安定に放電のできる０．０１～１．４Ｐａであることが好ましい。
　（ｃ）基板としては、ガラス基板中のアルカリ成分の拡散を防止する膜（例えば、酸化珪素膜）が形成された基板などを基体も用い得る。
　（ｄ）この方法には次に示す作用がある。酸化チタン膜は、特に大きな凹凸構造はなくほぼ平坦な膜である。酸化チタン膜は、その上に接して積層される酸化亜鉛系透明導電膜の結晶成長に影響を及ぼし、その結果、結晶成長が促進された結晶粒の大きな酸化亜鉛結晶が成長する。前記結晶粒に起因して酸化亜鉛系透明導電膜の表面が凹凸形状となる。結晶は、基体面に対してほほ垂直方向に配向しており、結晶方位が揃っているので、ほぼ形状が揃った凹凸が得られる。酸化亜鉛系透明導電膜は、凹凸形状が屋根型をしており、太陽電池の入射側電極として好適であり、光閉じ込め効果が高い。また、傾きが比較的なだらかな屋根型であるので、該　透明導電膜上に非晶質シリコン層を積層した場合、非晶質シリコン層が形成されない部分は極めて少なく、太陽電池として好適な連続した非晶質シリコン層となる。
　（ｅ）酸化チタン膜は、基板ガラスからのアルカリ分や水分の拡散を防止する効果もあり、酸化亜鉛系透明導電膜の劣化を防止できる。その結果、酸化チタン膜と透明導電膜が積層された基板を用いた太陽電池は信頼性が向上する。 Furthermore, Patent Document 5 (Japanese Patent Laid-Open No. 2001-015787) shows the following in general.
(A) From the viewpoint of obtaining a solar cell with high conversion efficiency, the titanium oxide film is a transparent film having high light transmittance. For example, a TiO2 film or another component (for example, SiO2, A film doped with Al2O3, Fe2O3) is mentioned. The film thickness is preferably 0.5 to 200 nm, particularly 1 to 10 nm. The form of the titanium oxide film may be either a continuous film or a discontinuous film.
As the oxide target for forming the titanium oxide film, TiO2 or TiO2-x is used. However, since TiO2 is not conductive, it is limited to a high frequency (RF) sputtering method, and in the case of TiO2-x. Is conductive, so that either direct current sputtering or radio frequency (RF) sputtering may be used.
The substrate temperature when the titanium oxide film is formed by sputtering is preferably 0 to 600 ° C. In particular, a temperature of 20 to 400 ° C. is preferable.
(B) Regarding the zinc oxide film, it is preferable that the surface uneven state has an arithmetic average roughness defined by JIS B0601 of 15 to 150 nm. If it is smaller than 15 nm, the light confinement effect tends to be low, and if it is larger than 150 nm, it is too rough and the film thickness of the photoelectric conversion layer formed on the film becomes non-uniform, or the portion where the photoelectric conversion layer is not formed As a result, power generation efficiency tends to decrease.
In addition, examples of the zinc oxide-based transparent conductive film include films in which ZnO is doped with another component (for example, one or more selected from the group consisting of B, Al, Ga, In, Si, and Ti) as a dopant. Yes. In particular, Al or Ga is preferable. The dopant content is preferably such that the total amount of dopant relative to the total amount of dopant and zinc (ZnO) is 0.01 to 10 atomic%.
The film thickness of the zinc oxide-based transparent conductive film is preferably 100 to 3000 nm. In particular, 100 to 1000 nm is preferable. When it is thinner than 100 nm, the uneven structure is difficult to appear. On the other hand, if it is thicker than 3000 nm, it takes time to form a film, which is not practical, and the amount of light absorption increases, resulting in a large loss of light energy. Moreover, as a form of a zinc oxide type transparent conductive film, it is preferable that it is a continuous film (film | membrane which has a film thickness of the grade which seems to be clearly continuous seeing with an electron microscope).
The substrate temperature when forming the zinc oxide-based transparent conductive film is preferably 0 to 600 ° C. In particular, a temperature of 20 to 400 ° C. is preferable.
Further, the sputtering pressure at the time of sputtering the zinc oxide-based transparent conductive film is not particularly limited, and is generally preferably 0.01 to 1.4 Pa at which stable discharge is possible.
(C) As a substrate, a substrate such as a substrate on which a film (for example, a silicon oxide film) for preventing diffusion of an alkali component in a glass substrate is formed may be used.
(D) This method has the following effects. The titanium oxide film is a substantially flat film without a particularly large uneven structure. The titanium oxide film affects the crystal growth of the zinc oxide-based transparent conductive film laminated on and in contact with the titanium oxide film, and as a result, a zinc oxide crystal having a large crystal grain in which the crystal growth is promoted grows. Due to the crystal grains, the surface of the zinc oxide-based transparent conductive film becomes uneven. Since the crystals are oriented in a substantially vertical direction with respect to the substrate surface and the crystal orientations are aligned, irregularities having substantially the same shape can be obtained. The zinc oxide-based transparent conductive film has a roof-like uneven shape, is suitable as an incident side electrode of a solar cell, and has a high light confinement effect. In addition, since the roof has a relatively gentle slope, when an amorphous silicon layer is laminated on the transparent conductive film, there are very few portions where the amorphous silicon layer is not formed, and it is a continuous suitable as a solar cell. It becomes an amorphous silicon layer.
(E) The titanium oxide film also has an effect of preventing diffusion of alkali and moisture from the substrate glass, and can prevent deterioration of the zinc oxide-based transparent conductive film. As a result, the reliability of the solar cell using the substrate on which the titanium oxide film and the transparent conductive film are stacked is improved.
　しかしながら、上記特許文献５（特開２００１－０１５７８７）に記載されている方法は、スパッタ法を用いる方法であるので、ターゲット材料が高価であること、及びスパッタ法でのターゲット材料の使用効率が低いことなどの問題を抱えている。その結果、その方法を用いて製造される太陽電池用基体の製造コストは高いものになる。 However, since the method described in Patent Document 5 (Japanese Patent Laid-Open No. 2001-015787) is a method using a sputtering method, the target material is expensive and the use efficiency of the target material in the sputtering method is low. Have such problems. As a result, the manufacturing cost of the solar cell substrate manufactured using the method is high.
　また、上記特許文献５（特開２００１－０１５７８７）には、スパッタ法を用いた、酸化チタンの製膜の方法及び酸化亜鉛を主成分とする透明導電膜の製膜の方法について記載されているものの、スパッタ法以外の方法及び装置については言及されていない。即ち、スパッタ法よりも製造コストが低くなる可能性のある方法や装置については言及されていない。また、酸化チタンの膜厚方向の特性の制御については言及されていない。 Patent Document 5 (Japanese Patent Application Laid-Open No. 2001-015787) describes a method for forming a titanium oxide film and a method for forming a transparent conductive film mainly composed of zinc oxide using a sputtering method. However, no method or apparatus other than the sputtering method is mentioned. That is, there is no mention of a method or apparatus that may have a lower manufacturing cost than the sputtering method. Further, there is no mention of controlling the characteristics of titanium oxide in the film thickness direction.
特開２００３－８１６３３JP 2003-81633 A 特許第３２１５１２８号Japanese Patent No. 3215128 特開２０００－１５０９２８JP2000-150928A 特開２００５－３１１２９２JP 2005-311292 A 特開２００１－０１５７８７JP 2001-015787 A
　上述の通り、従来技術では、熱ＣＶＤ法による酸化錫（ＳｎＯ２）を主成分とする透明電極が実用化されているが、製造コストの低減が困難であるという問題がある。
　また、最近、薄膜太陽電池業界では、基板サイズが第８世代（２．２ｍｘ２．６ｍ）という大面積基板の採用による生産コストの革新的低減の実現が強く求められている。しかしながら、従来の熱ＣＶＤ法では、高温プロセス特有の技術的困難性（ガラス基板厚みの増大、強化ガラス不採用に起因するガラスの割れなど）が伴うことから第８世代基板への対応は困難であるという問題がある。
　他方、上記熱ＣＶＤ法による酸化錫（ＳｎＯ２）を主成分とする透明電極の製造方法及び製造装置に代わる新しい方法及び装置として期待される上記特許文献２～５に記載の技術においては、上述したような諸問題があり、その実用化には無理があると考えられる。
　即ち、従来の方法および装置に比べて、生産コストが革新的に低減可能な新しい方法及び装置の創出が強く望まれている。 As described above, in the prior art, a transparent electrode mainly composed of tin oxide (SnO2) by a thermal CVD method has been put into practical use, but there is a problem that it is difficult to reduce the manufacturing cost.
Recently, in the thin film solar cell industry, there has been a strong demand for an innovative reduction in production cost by adopting a large area substrate with a substrate size of the 8th generation (2.2 mx 2.6 m). However, the conventional thermal CVD method is difficult to cope with the 8th generation substrate because it involves technical difficulties peculiar to high temperature processes (increased glass substrate thickness, glass breakage due to non-use of tempered glass, etc.). There is a problem that there is.
On the other hand, in the techniques described in Patent Documents 2 to 5, which are expected as new methods and apparatuses in place of the transparent electrode manufacturing method and manufacturing apparatus mainly composed of tin oxide (SnO2) by the thermal CVD method, There are various problems, and it seems impossible to put it into practical use.
That is, it is strongly desired to create a new method and apparatus capable of innovatively reducing the production cost as compared with the conventional method and apparatus.
　上記ニーズに対応するためには、従来技術に比べて安い製造コストで、実用性の高い新規の方法及び装置の開発が必要である。即ち、凹凸構造を有し、高導電性で、高光透過性で、かつ、低コストの透明電極を製造する方法及び装置を創出することが求められる。
　そのため、ここでは、薄膜太陽電池の製造コストの革新的低減を目指した新しいタイプの薄膜太陽電池用基板及びその製造方法、並びにそれを用いた薄膜太陽電池を創出することを課題とする。 In order to meet the above-described needs, it is necessary to develop a new method and apparatus having high practicality at a manufacturing cost lower than that of the prior art. That is, it is required to create a method and an apparatus for producing a transparent electrode having a concavo-convex structure, high conductivity, high light transmission, and low cost.
Therefore, it is an object of the present invention to create a new type of thin film solar cell substrate aiming at innovative reduction of the manufacturing cost of the thin film solar cell, a manufacturing method thereof, and a thin film solar cell using the same.
　本発明は、上記問題点に鑑みてなされたものであり、大面積の製膜が容易に可能で、かつ、低コストの原料である有機金属材料、例えば、トリメチル亜鉛やトリエチル亜鉛やジエチル亜鉛等を原料に使うことが可能である高周波プラズマＣＶＤ技術を用いた新しい方法及び装置を創出し、それに関する技術を提供することを目的とする。
　また、透明性絶縁基板の上に、非晶質酸化チタン膜と結晶性酸化チタン膜と結晶性酸化亜鉛膜を積層した薄膜太陽電池用基板及びその製造方法、並びにそれを用いた薄膜太陽電池を提供することを目的とする。 The present invention has been made in view of the above problems, and can be easily formed into a large area, and is a low-cost raw material such as an organometallic material such as trimethyl zinc, triethyl zinc, diethyl zinc, etc. An object is to create a new method and apparatus using high-frequency plasma CVD technology that can be used as a raw material, and to provide a technology related thereto.
Moreover, a thin film solar cell substrate in which an amorphous titanium oxide film, a crystalline titanium oxide film, and a crystalline zinc oxide film are laminated on a transparent insulating substrate, a manufacturing method thereof, and a thin film solar cell using the same The purpose is to provide.
　以下に、本発明を実施する為の最良の形態で使用される番号・符号を用いて、問題を解決する為の手段を説明する。これらの番号・符号は、特許請求の範囲の記載と発明を実施する為の最良の形態との対応関係を明らかにするために括弧付きで付加したものである。
　ただし、それらの番号・符号を、特許請求の範囲に記載されている発明の技術的範囲の解釈に用いてはならない。 Hereinafter, means for solving the problem will be described using the numbers and symbols used in the best mode for carrying out the present invention. These numbers and symbols are added in parentheses to clarify the correspondence between the description of the claims and the best mode for carrying out the invention.
However, these numbers and symbols should not be used for interpreting the technical scope of the invention described in the claims.
　上記目的を達成するために、本願に係わる第１の発明の薄膜太陽電池用基板は、透光性絶縁基板（２）、及び該透光性絶縁基板上に堆積された少なくとも酸化チタン膜層（３ａ）及び酸化亜鉛膜層（５）を含む透明電極層から成る薄膜太陽電池用基板（１ａ）であって、前記酸化チタン膜層（３ａ）は非晶質酸化チタン膜層（４ａ）と結晶質酸化チタン膜層（４ｂ）から成る２層構造を有することを特徴とする。 In order to achieve the above object, a substrate for a thin film solar cell according to a first aspect of the present invention includes a light-transmitting insulating substrate (2) and at least a titanium oxide film layer deposited on the light-transmitting insulating substrate ( 3a) and a thin film solar cell substrate (1a) comprising a transparent electrode layer including a zinc oxide film layer (5), wherein the titanium oxide film layer (3a) is formed of an amorphous titanium oxide film layer (4a) and a crystal. It has a two-layer structure composed of a quality titanium oxide film layer (4b).
　同様に、上記目的を達成するために、本願に係わる第２の発明の薄膜太陽電池用基板は、透光性絶縁基板（２）、及び該透光性絶縁基板上に堆積された少なくとも酸化チタン膜層（３ｂ）及び酸化亜鉛膜層（５）を含む透明電極層から成る薄膜太陽電池用基板（１ｂ）であって、前記酸化チタン膜層（３ｂ）は非晶質酸化チタン膜層（４ａ）と、非晶質酸化チタン及び微結晶酸化チタンが混在した混相酸化チタン膜層（４ｃ）と、結晶質酸化チタン膜層（４ｂ）から成る３層構造を有することを特徴とする。 Similarly, in order to achieve the above object, a substrate for a thin-film solar cell according to a second aspect of the present invention includes a translucent insulating substrate (2) and at least titanium oxide deposited on the translucent insulating substrate. A thin film solar cell substrate (1b) comprising a transparent electrode layer including a film layer (3b) and a zinc oxide film layer (5), wherein the titanium oxide film layer (3b) is an amorphous titanium oxide film layer (4a). ), A mixed phase titanium oxide film layer (4c) in which amorphous titanium oxide and microcrystalline titanium oxide are mixed, and a crystalline titanium oxide film layer (4b).
　同様に、上記目的を達成するために、本願に係わる第３の発明の薄膜太陽電池用基板は、透光性絶縁基板（２）、及び該透光性絶縁基板上に堆積された少なくとも酸化チタン膜層（３ｃ）及び酸化亜鉛膜層（５）を含む透明電極層から成る薄膜太陽電池用基板（１ｃ）であって、前記酸化チタン膜層（３ｃ）は非晶質酸化チタン及び微結晶酸化チタンが混在した混相酸化チタン膜層（４ｃ）と、結晶質酸化チタン膜層（４ｂ）から成る２層構造を有することを特徴とする。 Similarly, in order to achieve the above object, a substrate for a thin-film solar cell according to a third aspect of the present invention includes a translucent insulating substrate (2) and at least titanium oxide deposited on the translucent insulating substrate. A thin film solar cell substrate (1c) comprising a transparent electrode layer including a film layer (3c) and a zinc oxide film layer (5), wherein the titanium oxide film layer (3c) comprises amorphous titanium oxide and microcrystalline oxide It has a two-layer structure composed of a mixed phase titanium oxide film layer (4c) mixed with titanium and a crystalline titanium oxide film layer (4b).
　同様に、上記目的を達成するために、本願に係わる第４の発明の薄膜太陽電池用基板は、前記酸化亜鉛膜層（５）が結晶性を有することを特徴とする。 Similarly, in order to achieve the above object, the thin film solar cell substrate according to the fourth aspect of the present invention is characterized in that the zinc oxide film layer (5) has crystallinity.
　同様に、上記目的を達成するために、本願に係わる第５の発明の薄膜太陽電池用基板は、前記非晶質酸化チタン膜層（４ａ）の厚みが１ｎｍ～１５０ｎｍで、且つ、前記結晶質酸化チタン膜層（４ｂ）の厚みが５ｎｍ～２５０ｎｍであることを特徴とする。 Similarly, in order to achieve the above object, a thin film solar cell substrate according to a fifth aspect of the present invention has a thickness of the amorphous titanium oxide film layer (4a) of 1 nm to 150 nm and the crystalline material. The titanium oxide film layer (4b) has a thickness of 5 nm to 250 nm.
　同様に、上記目的を達成するために、本願に係わる第６の発明の薄膜太陽電池用基板は、前記非晶質酸化チタン及び微結晶酸化チタンが混在した混相酸化チタン膜層（４ｃ）の厚みが１０ｎｍ～１００ｎｍであることを特徴とする。 Similarly, in order to achieve the above object, the substrate for a thin film solar cell according to the sixth aspect of the present invention is the thickness of the mixed phase titanium oxide film layer (4c) in which the amorphous titanium oxide and the microcrystalline titanium oxide are mixed. Is 10 nm to 100 nm.
　同様に、上記目的を達成するために、本願に係わる第７の発明の薄膜太陽電池用基板の製造方法は、前記薄膜太陽電池用基板（１ａ、１ｂ、１ｃ）の製造方法であって、前記非晶質酸化チタン膜層（４ａ）、前記結晶質酸化チタン膜層（４ｂ）及び前記酸化亜鉛膜層（５）は、いずれも高周波プラズマＣＶＤ装置を用いて製造されることを特徴とする。 Similarly, in order to achieve the above object, a method for manufacturing a thin-film solar cell substrate according to a seventh aspect of the present invention is a method for manufacturing the thin-film solar cell substrate (1a, 1b, 1c), The amorphous titanium oxide film layer (4a), the crystalline titanium oxide film layer (4b) and the zinc oxide film layer (5) are all manufactured using a high-frequency plasma CVD apparatus.
　同様に、上記目的を達成するために、本願に係わる第８の発明の薄膜太陽電池用基板の製造方法は、前記非晶質酸化チタン膜層（４ａ）及び前記結晶質酸化チタン膜層（４ｂ）が高周波プラズマＣＶＤ装置を用いて製造され、且つ、前記酸化亜鉛膜層（５）がスパッタ装置を用いて製造されることを特徴とする。 Similarly, in order to achieve the above object, a method for manufacturing a thin-film solar cell substrate according to an eighth aspect of the present invention includes the amorphous titanium oxide film layer (4a) and the crystalline titanium oxide film layer (4b). ) Is manufactured using a high-frequency plasma CVD apparatus, and the zinc oxide film layer (5) is manufactured using a sputtering apparatus.
　同様に、上記目的を達成するために、本願に係わる第９の発明の薄膜太陽電池用基板の製造方法は、前記非晶質酸化チタン膜層（４ａ）及び前記結晶質酸化チタン膜層（４ｂ）が、前記透光性絶縁基板（２）の温度２５０～４５０℃で製造され、且つ、前記酸化亜鉛膜層（５）は前記透光性絶縁基板（２）の温度１５０～４５０℃で製造されることを特徴とする。 Similarly, in order to achieve the above object, a method for manufacturing a thin film solar cell substrate according to a ninth aspect of the present invention relates to the amorphous titanium oxide film layer (4a) and the crystalline titanium oxide film layer (4b). ) Is manufactured at a temperature of 250 to 450 ° C. of the translucent insulating substrate (2), and the zinc oxide film layer (5) is manufactured at a temperature of 150 to 450 ° C. of the translucent insulating substrate (2). It is characterized by being.
　同様に、上記目的を達成するために、本願に係わる第１０の発明の薄膜太陽電池用基板の製造方法は、前記非晶質酸化チタン膜層が前記透光性絶縁基板（２）の温度２５０℃以下で製造され、且つ、前記結晶質酸化チタン膜層（４ｂ）が前記透光性絶縁基板（２）の温度２５０～４５０℃で、且つ、前記酸化亜鉛膜層（５）が前記透光性絶縁基板（２）の温度１５０～４５０℃で製造されることを特徴とする。 Similarly, in order to achieve the above object, in the method for manufacturing a thin film solar cell substrate according to the tenth aspect of the present invention, the amorphous titanium oxide film layer has a temperature 250 of the translucent insulating substrate (2). The crystalline titanium oxide film layer (4b) is manufactured at a temperature of 250 to 450 ° C. of the translucent insulating substrate (2), and the zinc oxide film layer (5) is the translucent film. The insulating insulating substrate (2) is manufactured at a temperature of 150 to 450 ° C.
　同様に、上記目的を達成するために、本願に係わる第１１の発明の薄膜太陽電池用基板の製造方法は、前記非晶質酸化チタン膜層（４ａ）及び前記結晶質酸化チタン膜層（４ｂ）を高周波プラズマＣＶＤ法で製膜する際に、原料として、少なくともチタニウムテトライソプロポキシドと酸素の混合ガスを用い、且つ、前記透光性絶縁基板（２）の温度が２５０～４５０℃で製造されることを特徴とする。 Similarly, in order to achieve the above object, a method for manufacturing a thin film solar cell substrate according to an eleventh aspect of the present invention includes the amorphous titanium oxide film layer (4a) and the crystalline titanium oxide film layer (4b). ) Using a high-frequency plasma CVD method, at least a mixed gas of titanium tetraisopropoxide and oxygen is used as a raw material, and the temperature of the translucent insulating substrate (2) is 250 to 450 ° C. It is characterized by being.
　同様に、上記目的を達成するために、本願に係わる第１２の発明の薄膜太陽電池用基板の製造方法は、前記非晶質酸化チタン膜層（４ａ）及び前記結晶質酸化チタン膜層（４ｂ）の製造の際に、前記透光性絶縁基板（２）の温度を２５０℃～４５０℃に設定し、且つ、原料に少なくともチタニウムテトライソプロポキシドと酸素の混合ガスを用いた高周波プラズマＣＶＤ法を用い、且つ、その堆積初期に形成される非晶質酸化チタン膜層（４ａ）を前記透光性絶縁基板（２）からの不純物のバリア層として用い、且つ、該非晶質酸化チタン膜層（４ａ）を下地として形成される結晶質酸化チタン膜層（４ｂ）を酸化亜鉛膜層（５）の製膜の際の下地層に用いることを特徴とする。 Similarly, in order to achieve the above object, a method for manufacturing a thin film solar cell substrate according to a twelfth aspect of the present invention includes the amorphous titanium oxide film layer (4a) and the crystalline titanium oxide film layer (4b). ), The temperature of the translucent insulating substrate (2) is set to 250 ° C. to 450 ° C., and at least a mixed gas of titanium tetraisopropoxide and oxygen is used as a raw material. And the amorphous titanium oxide film layer (4a) formed at the initial deposition stage is used as a barrier layer for impurities from the translucent insulating substrate (2), and the amorphous titanium oxide film layer A crystalline titanium oxide film layer (4b) formed using (4a) as a base is used as a base layer in forming the zinc oxide film layer (5).
　同様に、上記目的を達成するために、本願に係わる第１３の発明の薄膜太陽電池は、光電変換層（７、１３）に少なくとも非晶質シリコンあるいは微結晶シリコンが含まれることを特徴とする。 Similarly, in order to achieve the above object, a thin film solar cell according to a thirteenth aspect of the present invention is characterized in that at least amorphous silicon or microcrystalline silicon is contained in the photoelectric conversion layers (7, 13). .
　本発明によれば、光透過性絶縁基板上に、非晶質酸化チタンと結晶質酸化チタンと、ＧａあるいはＡｌがドープされた結晶粒径の大きい結晶質酸化亜鉛が積層された薄膜太陽電池用基板を製造可能である。その結果、ナトリウムの拡散防止が可能で、高導電性で、高光透過性で、かつ、凹凸構造を有する薄膜太陽電池用基板を製造可能である。
　この薄膜太陽電池用基板をアモルファスシリコン太陽電池及びタンデム型太陽電池の透明電極として用いることにより、高い光電変換効率を有する太陽電池の製造が可能である。
　また、本発明によれば、酸化チタン膜及び酸化亜鉛膜からなる透明電極の製造に安価な有機金属材料を用い、且つ、大面積基板への応用が容易な高周波プラズマＣＶＤ法を用いることが可能であることから、薄膜太陽電池の製造コストの革新的低減が可能である。 According to the present invention, a thin film solar cell in which amorphous titanium oxide, crystalline titanium oxide, and crystalline zinc oxide with a large crystal grain size doped with Ga or Al are laminated on a light-transmitting insulating substrate. A substrate can be manufactured. As a result, it is possible to manufacture a thin film solar cell substrate that can prevent sodium diffusion, has high conductivity, high light transmittance, and has an uneven structure.
By using this thin film solar cell substrate as a transparent electrode of an amorphous silicon solar cell and a tandem solar cell, it is possible to manufacture a solar cell having high photoelectric conversion efficiency.
In addition, according to the present invention, it is possible to use an inexpensive organometallic material for manufacturing a transparent electrode made of a titanium oxide film and a zinc oxide film and to use a high-frequency plasma CVD method that can be easily applied to a large area substrate. Therefore, the manufacturing cost of the thin film solar cell can be innovatively reduced.
本発明の第１の実施形態に係わる薄膜太陽電池用基板の断面を概略的に示す構造図。1 is a structural diagram schematically showing a cross section of a thin-film solar cell substrate according to a first embodiment of the present invention. 本発明の第１の実施形態に係わる酸化チタン（ＴｉＯ２）膜を製造するための高周波プラズマＣＶＤ装置の概略を示す装置構成図。1 is an apparatus configuration diagram schematically showing a high-frequency plasma CVD apparatus for manufacturing a titanium oxide (TiO 2) film according to a first embodiment of the present invention. 本発明の第１の実施形態に係わる酸化亜鉛（ＺｎＯ）膜を製造するための高周波プラズマＣＶＤ装置の概略を示す装置構成図。1 is an apparatus configuration diagram schematically showing a high-frequency plasma CVD apparatus for manufacturing a zinc oxide (ZnO) film according to a first embodiment of the present invention. 本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化チタン膜を製造する際の、基板温度が低温域（常温～２５０℃）で、下地がガラスの場合における製膜時間と製膜される膜の厚みと膜質の関係を示す説明図。When the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention, the substrate temperature is a low temperature range (room temperature to 250 ° C.), and the film formation time is the same as that when the substrate is glass. Explanatory drawing which shows the relationship between the thickness of a film and film quality. 本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化チタン膜を製造する際の、基板温度が中温域（２５０～３５０℃）で、下地がガラスの場合における製膜時間と製膜される膜の厚みと膜質の関係を示す説明図。When the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention, the substrate temperature is in the middle temperature range (250 to 350 ° C.), and the film formation time is the same as that in the case where the substrate is glass. Explanatory drawing which shows the relationship between the thickness of a film and film quality. 本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化チタン膜を製造する際の、基板温度が高温域（３５０～４５０℃）で、下地がガラスの場合における製膜時間と製膜される膜の厚みと膜質の関係を示す説明図。When the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention, the substrate temperature is in a high temperature range (350 to 450 ° C.) and the film is formed with the film formation time in the case where the substrate is glass. Explanatory drawing which shows the relationship between the thickness of a film and film quality. 本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化チタン膜を製造する際の、基板温度が高温域（３５０～４５０℃）で、下地が非晶質酸化チタン、あるいは非晶質酸化チタンと微結晶酸化チタンの混相、あるいは結晶質酸化チタンにおける製膜時間と製膜される膜の厚みと膜質の関係を示す説明図。When manufacturing a titanium oxide film by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention, the substrate temperature is in a high temperature range (350 to 450 ° C.) and the base is amorphous titanium oxide or amorphous oxide. Explanatory drawing which shows the relationship between the mixed phase of titanium and microcrystalline titanium oxide, or the film formation time in crystalline titanium oxide, the thickness of the film formed, and film quality. 本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化亜鉛膜を製造する際の、基板温度が約２００～４００℃で、下地が結晶質酸化チタンにおける製膜時間と製膜される膜の厚みと膜質の関係を示す説明図。Film for forming a zinc oxide film by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention when the substrate temperature is about 200 to 400 ° C. and the base is crystalline titanium oxide and the film is formed. Explanatory drawing which shows the relationship between thickness and film quality. 本発明の第１の実施形態に係わる薄膜太陽電池用基板のアモルファスシリコン太陽電池製造への応用の説明図。Explanatory drawing of the application to the amorphous silicon solar cell manufacture of the board | substrate for thin film solar cells concerning the 1st Embodiment of this invention. 本発明の第１の実施形態に係わる薄膜太陽電池用基板のタンデム型薄膜太陽電池製造への応用の説明図。Explanatory drawing of the application to the tandem-type thin film solar cell manufacture of the board | substrate for thin film solar cells concerning the 1st Embodiment of this invention. 本発明の第２の実施形態に係わる薄膜太陽電池用基板の断面を概略的に示す構造図。FIG. 5 is a structural diagram schematically showing a cross section of a thin film solar cell substrate according to a second embodiment of the present invention. 本発明の第３の実施形態に係わる薄膜太陽電池用基板の断面を概略的に示す構造図。FIG. 5 is a structural diagram schematically showing a cross section of a thin-film solar cell substrate according to a third embodiment of the present invention.
符号の説明Explanation of symbols
１ａ・・・本発明の第１の実施形態に係わる薄膜太陽電池用基板、
２・・・透光性絶縁基板、
４ａ・・・非晶質酸化チタン層、
４ｂ・・・結晶質酸化チタン層、
４ｃ・・・非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン膜、
５・・・結晶質酸化亜鉛（ＺｎＯ）膜層、
１００・・・真空容器、
１０１・・・非接地の第１の電極、
１０３・・・接地された第２の電極、
１２０ａ・・・酸化チタン膜の原料、
１２０ｂ・・・酸化亜鉛膜の原料、
１２０ｃ・・・酸化亜鉛膜のドーピング材料、
１３５・・・発信器、
１３８ａ、１３８ｂ・・・第１及び第２の電力増幅器、
１３９ａ、１３９ｂ・・・第１及び第２の整合器。 1a: Substrate for thin film solar cell according to the first embodiment of the present invention,
2 ... Translucent insulating substrate,
4a ... amorphous titanium oxide layer,
4b ... crystalline titanium oxide layer,
4c: mixed phase titanium oxide film of amorphous titanium oxide and crystalline titanium oxide,
5 ... crystalline zinc oxide (ZnO) film layer,
100 ... Vacuum container,
101 ... Ungrounded first electrode,
103 ... a second electrode grounded;
120a: raw material for titanium oxide film,
120b ... Raw material of zinc oxide film,
120c ... doping material of zinc oxide film,
135: Transmitter,
138a, 138b... First and second power amplifiers,
139a, 139b... First and second matching units.
　以下、本発明を実施するための最良の形態について、図面を参照しながら詳細に説明する。なお、各図において、同様の部材には同一の符号を付し、重複する説明は省略する。 Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the same member, and the overlapping description is abbreviate | omitted.
　先ず、本発明の第１の実施形態に係わる薄膜太陽電池用基板及びその製造方法について、図１ないし図１０を参照して説明する。
　図１は、本発明の第１の実施形態に係わる薄膜太陽電池用基板の断面を概略的に示す構造図である。
　図２は、本発明の第１の実施形態に係わる酸化チタン（ＴｉＯ２）膜を製造するための高周波プラズマＣＶＤ装置の概略を示す装置構成図である。
　図３は、本発明の第１の実施形態に係わる酸化亜鉛（ＺｎＯ）膜を製造するための高周波プラズマＣＶＤ装置の概略を示す装置構成図である。
　図４は、本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化チタン膜を製造する際の、基板温度が低温域（常温～２５０℃）で、下地がガラスの場合における製膜時間と製膜される膜の厚みと膜質の関係を示す説明図である。
　図５は、本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化チタン膜を製造する際の、基板温度が中温域（２５０～３５０℃）で、下地がガラスの場合における製膜時間と製膜される膜の厚みと膜質の関係を示す説明図である。
　図６は、本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化チタン膜を製造する際の、基板温度が高温域（３５０～４５０℃）で、下地がガラスの場合における製膜時間と製膜される膜の厚みと膜質の関係を示す説明図である。
　図７は、本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化チタン膜を製造する際の、基板温度が高温域（３５０～４５０℃）で、下地が非晶質酸化チタン、あるいは非晶質酸化チタンと微結晶酸化チタンの混相、あるいは結晶質酸化チタンにおける製膜時間と製膜される膜の厚みと膜質の関係を示す説明図である。
　図８は、本発明の第１の実施形態に係わる高周波プラズマＣＶＤ装置による酸化亜鉛膜を製造する際の、基板温度が約２００～４００℃で、下地が結晶質酸化チタンにおける製膜時間と製膜される膜の厚みと膜質の関係を示す説明図である。
　図９は、本発明の第１の実施形態に係わる薄膜太陽電池用基板のアモルファスシリコン太陽電池製造への応用の説明図である。
　図１０は、本発明の第１の実施形態に係わる薄膜太陽電池用基板のタンデム型薄膜太陽電池製造への応用の説明図である。 First, a thin film solar cell substrate and a manufacturing method thereof according to the first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a structural view schematically showing a cross section of a thin film solar cell substrate according to a first embodiment of the present invention.
FIG. 2 is an apparatus configuration diagram showing an outline of a high-frequency plasma CVD apparatus for producing a titanium oxide (TiO 2) film according to the first embodiment of the present invention.
FIG. 3 is an apparatus configuration diagram showing an outline of a high-frequency plasma CVD apparatus for manufacturing a zinc oxide (ZnO) film according to the first embodiment of the present invention.
FIG. 4 shows the film formation time when the substrate temperature is low (room temperature to 250 ° C.) and the substrate is glass when manufacturing the titanium oxide film by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention. It is explanatory drawing which shows the relationship between the thickness of the film | membrane formed, and film quality.
FIG. 5 shows the film formation time when the substrate temperature is in the intermediate temperature range (250 to 350 ° C.) and the substrate is glass when the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention. It is explanatory drawing which shows the relationship between the thickness of the film | membrane formed, and film quality.
FIG. 6 shows the film formation time in the case where the substrate temperature is high (350 to 450 ° C.) and the substrate is glass when the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention. It is explanatory drawing which shows the relationship between the thickness of the film | membrane formed, and film quality.
FIG. 7 shows a substrate temperature in the high temperature region (350 to 450 ° C.) when the titanium oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention, and the base is amorphous titanium oxide. It is explanatory drawing which shows the mixed phase of an amorphous titanium oxide and a microcrystal titanium oxide, or the relationship between the film formation time in crystalline titanium oxide, the thickness of the film formed, and film quality.
FIG. 8 shows the film formation time and the manufacturing time when the substrate temperature is about 200 to 400 ° C. and the base is crystalline titanium oxide when the zinc oxide film is manufactured by the high-frequency plasma CVD apparatus according to the first embodiment of the present invention. It is explanatory drawing which shows the relationship between the thickness of the film | membrane formed, and film quality.
FIG. 9 is an explanatory diagram of application of the thin film solar cell substrate according to the first embodiment of the present invention to the manufacture of an amorphous silicon solar cell.
FIG. 10 is an explanatory diagram of application of the thin film solar cell substrate according to the first embodiment of the present invention to manufacture of a tandem thin film solar cell.
　先ず、本発明の第１の実施形態に係わる薄膜太陽電池用基板の構成について、説明する。
　図１において、符号１ａは、本発明の第１の実施形態に係わる薄膜太陽電池用基板である。本発明の第１の実施形態に係わる薄膜太陽電池用基板１ａは、後述の透光性絶縁基板２、酸化チタン層３ａ（これは、非晶質酸化チタン層４ａと結晶質酸化チタン層４ｂから構成される）及び結晶質酸化亜鉛（ＺｎＯ）膜層５により構成される。 First, the structure of the thin film solar cell substrate according to the first embodiment of the present invention will be described.
In FIG. 1, the code | symbol 1a is a board | substrate for thin film solar cells concerning the 1st Embodiment of this invention. A thin film solar cell substrate 1a according to the first embodiment of the present invention includes a translucent insulating substrate 2 and a titanium oxide layer 3a (described later from an amorphous titanium oxide layer 4a and a crystalline titanium oxide layer 4b). And a crystalline zinc oxide (ZnO) film layer 5.
　図１において、符号２は、透光性絶縁基板で、例えば厚みが４～５ｍｍのガラス基板である。
　符号３ａは酸化チタン層で、非晶質酸化チタン層４ａと結晶質酸化チタン層４ｂの２層から構成される。非晶質酸化チタン層４ａ及び結晶質酸化チタン層４ｂは、後述するように、アルゴンガスあるいは水素ガスをキャリアガスとして用い、チタニウムテトライソプロポキシド：Ｔｉｔａｎｉｕｍ－Ｔｅｔｒａ－Ｉｓｏ－Ｐｒｏｐｏｘｉｄｅ（ここでは、ＴＴＩＰと呼ぶ）と酸素を主原料として、高周波プラズマＣＶＤ装置により製膜される。
　符号５は結晶質酸化亜鉛（ＺｎＯ）膜層である。この結晶質酸化亜鉛（ＺｎＯ）膜層は、後述するように、アルゴンガスあるいは水素ガスをキャリアガスとして用い、トリメチル亜鉛（ＣＨ３）３Ｚｎあるいはトリエチル亜鉛（Ｃ２Ｈ５）３Ｚｎと酸素の混合ガスを主原料として、高周波プラズマＣＶＤ装置により製膜される。また、この結晶質酸化亜鉛（ＺｎＯ）膜層５の製膜は、スパッタ装置を用いてもよい。
　なお、上記結晶質酸化亜鉛（ＺｎＯ）膜層５の製膜においては、導電性を高めるために、ドーピング材料として、トリメチルガリウム（ＣＨ３）３Ｇａ、トリエチルガリウム（Ｃ２Ｈ５）３Ｇａ、トリメチルアルミニウム（ＣＨ３）３Ａｌ、トリエチルアルミニウム（Ｃ２Ｈ５）３Ａｌなどを用いる。 In FIG. 1, reference numeral 2 denotes a translucent insulating substrate, for example, a glass substrate having a thickness of 4 to 5 mm.
Reference numeral 3a denotes a titanium oxide layer, which is composed of two layers, an amorphous titanium oxide layer 4a and a crystalline titanium oxide layer 4b. As will be described later, the amorphous titanium oxide layer 4a and the crystalline titanium oxide layer 4b are made of titanium tetraisopropoxide: Titanium-Tetra-Iso-Propoxide (here, TTIP) using argon gas or hydrogen gas as a carrier gas. ) And oxygen as a main raw material, and is formed by a high-frequency plasma CVD apparatus.
Reference numeral 5 denotes a crystalline zinc oxide (ZnO) film layer. As will be described later, this crystalline zinc oxide (ZnO) film layer uses argon gas or hydrogen gas as a carrier gas, and uses trimethylzinc (CH 3 ) 3 Zn or triethylzinc (C 2 H 5 ) 3 Zn and oxygen. The mixed gas is used as a main raw material to form a film by a high frequency plasma CVD apparatus. In addition, the crystalline zinc oxide (ZnO) film layer 5 may be formed by using a sputtering apparatus.
Note that, in the formation of the crystalline zinc oxide (ZnO) film layer 5, as doping materials, trimethylgallium (CH 3 ) 3 Ga, triethylgallium (C 2 H 5 ) 3 Ga, Trimethylaluminum (CH 3 ) 3 Al, triethylaluminum (C 2 H 5 ) 3 Al, or the like is used.
　次に、本発明の第１の実施形態に係わる薄膜太陽電池用基板を製造するために用いられる酸化チタン（ＴｉＯ２）膜製造用の高周波プラズマＣＶＤ装置の構成について、説明する。 Next, the configuration of a high-frequency plasma CVD apparatus for manufacturing a titanium oxide (TiO 2) film used for manufacturing the thin film solar cell substrate according to the first embodiment of the present invention will be described.
　図２において、符号１００は、真空容器である。この真空容器１００には、後述の原料ガスをプラズマ化する一対の電極、即ち非接地の第１の電極１０１と図示しない基板ヒータ１０２を内臓した接地された第２の電極１０３が配置されている。
　符号１０１は第１の電極で、図示しない絶縁物支持材１０４及びガス混合箱１０５を介して真空容器１００に固着されている。第１の電極１０１は、矩形の平板型であり、後述する第２の電極１０３に対向して設置される。その具体的なサイズは、例えば、外寸法で、長さ１．５ｍｘ幅０．３ｍｘ厚み２０ｍｍとする。
　また、第１の電極１０１及びガス混合器１０５は、図１に示すように、それぞれ、原料ガスが噴出するガスシャワー孔１０６及び１０７を有している。この孔１０６及び１０７は、直径約０．４～１ｍｍで、例えば直径約０．７ｍｍで、多数個が設定される。なお、ガスシャワー孔１０７は後述の酸素ガスを、ガスシャワー孔１０６を介して一対の電極１０１、１０３間に均一に供給するための整流の機能を有する。また、ガスシャワー孔１０６は、後述のキャリアガスとチタニウムテトライソプロポキシド（ここでは、ＴＴＩＰと呼ぶ）の混合ガス、及び上記酸素ガスを一対の電極１０１、１０３間に均一に供給するための整流の機能を有する。
　符号１０３は第２の電極で、図示しない基板ヒータ１０２を内臓し、その上に設置される基板１０８の温度を１００～４５０℃の範囲で、任意の温度に設定可能である。なお、第２の電極１０３は基板ヒータ１０２の他に、冷媒を通すパイプを内蔵して、第２の電極１０３の表面の温度を制御することが可能である。
　第２の電極１０３は、矩形の平板型であり、第１の電極１０１に対向して設置される。その具体的なサイズは、例えば、外寸法で、長さ１．６ｍｘ幅０．４ｍｘ厚み１５０ｍｍとする。
　符号１０９は、原料ガス温度調整装置で、後述の原料ガス、即ち、キャリアガスとＴＴＩＰの混合ガスの温度を後述のＴＴＩＰ温度調整装置１２２ａの設定値よりも１０～３０℃高く保つために、ガス混合箱１０５及び第１の電極１０１の温度を、例えば、９０℃に保持する機能を有する。 In FIG. 2, the code | symbol 100 is a vacuum vessel. The vacuum vessel 100 is provided with a pair of electrodes for converting a source gas to be described later into plasma, that is, a non-grounded first electrode 101 and a grounded second electrode 103 containing a substrate heater 102 (not shown). .
Reference numeral 101 denotes a first electrode, which is fixed to the vacuum vessel 100 via an insulator support member 104 and a gas mixing box 105 (not shown). The first electrode 101 has a rectangular flat plate shape, and is disposed to face a second electrode 103 described later. The specific size is, for example, an external dimension of length 1.5 mx width 0.3 mx thickness 20 mm.
In addition, as shown in FIG. 1, the first electrode 101 and the gas mixer 105 have gas shower holes 106 and 107 through which the source gas is ejected, respectively. The holes 106 and 107 have a diameter of about 0.4 to 1 mm, for example, a diameter of about 0.7 mm, and a large number of holes 106 and 107 are set. Note that the gas shower hole 107 has a function of rectification for uniformly supplying oxygen gas, which will be described later, between the pair of electrodes 101 and 103 through the gas shower hole 106. The gas shower hole 106 is a rectifier for uniformly supplying a mixed gas of a carrier gas and titanium tetraisopropoxide (hereinafter referred to as TTIP), which will be described later, and the oxygen gas between the pair of electrodes 101 and 103. It has the function of.
Reference numeral 103 denotes a second electrode which includes a substrate heater 102 (not shown), and the temperature of the substrate 108 placed thereon can be set to an arbitrary temperature within a range of 100 to 450 ° C. Note that, in addition to the substrate heater 102, the second electrode 103 can include a pipe through which a refrigerant is passed to control the surface temperature of the second electrode 103.
The second electrode 103 has a rectangular flat plate shape and is disposed to face the first electrode 101. The specific size is, for example, an external dimension of length 1.6 mx width 0.4 mx thickness 150 mm.
Reference numeral 109 denotes a raw material gas temperature adjusting device, which is a gas for maintaining the temperature of a raw material gas described later, that is, a mixed gas of carrier gas and TTIP, by 10 to 30 ° C. higher than a set value of a TTIP temperature adjusting device 122a described later. For example, the temperature of the mixing box 105 and the first electrode 101 is maintained at 90 ° C.
　図２において、第１の電極１０１には、第１及び第２の給電点１１０ａ、１１０ｂが配置される。第１及び第２の給電点１１０ａ、１１０ｂは、後述の電力供給系と第１の電極１０１との接続点であり、その位置から電力が供給される。また、第１及び第２の給電点１１０ａ、１１０ｂは、互いに対向した位置関係にあり、且つ、該電極の端部に設定され、高周波電力波の伝播上での対向点となる関係を有する。
　第２の電極１０３には、第３及び第４の給電点１１１ａ、１１１ｂが配置される。第３及び第４の給電点１１１ａ、１１１ｂは、後述の電力供給系と電極１０３との接続点であり、その位置から電力が供給される。また、第３及び第４の給電点１１１ａ、１１１ｂは、互いに対向した位置関係にあり、且つ、該電極の端部に設定され、高周波電力波の伝播上での対向点となる関係を有する。 In FIG. 2, first and second feeding points 110 a and 110 b are arranged on the first electrode 101. The first and second feeding points 110a and 110b are connection points between a power supply system, which will be described later, and the first electrode 101, and power is supplied from these positions. In addition, the first and second feeding points 110a and 110b are in a positional relationship facing each other, and are set at the ends of the electrodes and have a relationship as opposing points on the propagation of the high-frequency power wave.
Third and fourth feeding points 111 a and 111 b are arranged on the second electrode 103. The third and fourth feeding points 111a and 111b are connection points between a power supply system described later and the electrode 103, and power is supplied from the positions. In addition, the third and fourth feeding points 111a and 111b are in a positional relationship facing each other, and are set at the ends of the electrodes and have a relationship as opposing points in the propagation of the high-frequency power wave.
　第１及び第２の電極１０１、１０３の間隔は、後述の基板リフター１１２を上下に作動させる際に、予め、任意に設定可能であり、５ｍｍ～４０ｍｍの範囲で、例えば２５ｍｍに設定する。 The distance between the first and second electrodes 101 and 103 can be arbitrarily set in advance when a substrate lifter 112 described later is operated up and down, and is set to a range of 5 mm to 40 mm, for example, 25 mm.
　図２において、符号１１２は基板リフターで、図示しない基板搬入出ゲート１１８から第２の電極１０３上に基板１０８を受け取り、第１及び第２の電極との間隔を所定の値に保つ位置まで、例えば、第１及び第２の電極１０１、１０３の間隔が２５ｍｍになる位置まで移動する。
　なお、基板リフター１１２の上下位置は任意に設定可能であり、第１及び第２の電極間を、例えば、５ｍｍ～４０ｍｍの範囲に設定する。
　基板リフター１１２の上下動の際、真空容器１００の気密を保持するためにベローズ１１３が用いられる。
　また、後述するように、第２の電極１０３と真空容器１００の内壁との通電を良くするために、真空容器１００内壁に固着されている第１の接続導体１１５ａと第２の接続導体１１５ｂ、第２の電極１０３に固着されている第３の接続導体１１６ａと第４の接続導体１１６ｂが設置されている。なお、上記第１及び第２の電極の間隔に対応して、第１の接続導体１１５ａ及び第２の接続導体１１５ｂの取り付け位置は、任意に設定できる。
　また、第１の接続導体１１５ａと第３の接続導体１１６ａ、及び第２の接続導体１１５ｂと第４の接続導体１１６ｂは、それぞれが接触した際に、互いに押し付けあうように、バネの特性を有している。なお、第１の接続導体１１５ａと第３の接続導体１１６ａ、及び第２の接続導体１１５ｂと第４の接続導体１１６ｂは、それぞれが再現性良く、導通状態を確保できるように設定される。
　符号１０８は基板で、基板リフター１１２及び図示しない基板搬入出ゲート１１８を用いて、第２の電極１０３上に配置される。そして、図示しない基板ヒータ１０２により所定の温度に加熱される。ここでは、基板１０８は、サイズ１．５ｍｘ０．２５ｍｘ厚み４ｍｍのガラスを用いる。 In FIG. 2, reference numeral 112 denotes a substrate lifter, which receives the substrate 108 on the second electrode 103 from a substrate carry-in / out gate 118 (not shown), up to a position where the distance between the first and second electrodes is maintained at a predetermined value. For example, the first and second electrodes 101 and 103 move to a position where the distance is 25 mm.
The vertical position of the substrate lifter 112 can be arbitrarily set, and the distance between the first and second electrodes is set in a range of 5 mm to 40 mm, for example.
A bellows 113 is used to keep the vacuum vessel 100 airtight when the substrate lifter 112 moves up and down.
Further, as will be described later, in order to improve the energization between the second electrode 103 and the inner wall of the vacuum vessel 100, a first connection conductor 115a and a second connection conductor 115b fixed to the inner wall of the vacuum vessel 100, A third connection conductor 116a and a fourth connection conductor 116b fixed to the second electrode 103 are provided. Note that the attachment positions of the first connection conductor 115a and the second connection conductor 115b can be arbitrarily set according to the distance between the first and second electrodes.
Further, the first connection conductor 115a and the third connection conductor 116a, and the second connection conductor 115b and the fourth connection conductor 116b have a spring characteristic so that they are pressed against each other when they are in contact with each other. is doing. Note that the first connection conductor 115a and the third connection conductor 116a, and the second connection conductor 115b and the fourth connection conductor 116b are set so as to ensure a conductive state with good reproducibility.
Reference numeral 108 denotes a substrate, which is disposed on the second electrode 103 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown). Then, it is heated to a predetermined temperature by a substrate heater 102 (not shown). Here, the substrate 108 is made of glass having a size of 1.5 mx 0.25 mx 4 mm in thickness.
　図２において、ガス混合箱１０５は、後述の第１の原料ガス供給管１２６ａより、原料ガス供給部１３２を介して供給されるキャリアガスとＴＴＩＰの混合ガスをガスシャワー孔１０６を介して、前記一対の電極１０１と１０３の間に均一に供給する機能を有している。なお、原料ガス供給部１３２は図示しない絶縁材で構成され、電気的に絶縁されている。
　また、後述の第２の原料ガス供給管１３０より供給される酸素ガスをガスシャワー孔１０７と１０６を介して、前記一対の電極１０１と１０３の間に均一に供給する機能を有している。なお、第２の原料ガス供給管１３０は図示しない絶縁材で構成され、電気的に絶縁されている。
　供給されたＴＴＩＰ及び酸素等の原料ガスは、前記一対の電極１０１、１０３の間でプラズマ化された後、排気管１１９ａ、１１９ｂ及び図示しない真空ポンプにより、真空容器１００の外部へ排出される。 In FIG. 2, the gas mixing box 105 is configured such that a mixed gas of carrier gas and TTIP supplied from a first source gas supply pipe 126 a to be described later via a source gas supply unit 132 passes through the gas shower hole 106. It has a function of supplying uniformly between the pair of electrodes 101 and 103. The source gas supply unit 132 is made of an insulating material (not shown) and is electrically insulated.
Further, it has a function of uniformly supplying oxygen gas supplied from a second source gas supply pipe 130 described later between the pair of electrodes 101 and 103 through the gas shower holes 107 and 106. The second source gas supply pipe 130 is made of an insulating material (not shown) and is electrically insulated.
The supplied source gas such as TTIP and oxygen is turned into plasma between the pair of electrodes 101 and 103 and then discharged to the outside of the vacuum vessel 100 by the exhaust pipes 119a and 119b and a vacuum pump (not shown).
　図２において、符号１２０ａは、ＴＴＩＰで、酸化チタン膜の原料である。符号１２１ａはＴＴＩＰの容器で、後述のＴＴＩＰ温度調整装置１２２ａと組み合わせて用いられる。符号１２２ａはＴＴＩＰ温度調整装置で、ＴＴＩＰの容器１２１ａの温度を、６５～９０℃の範囲の任意の温度、例えば７０℃に保持する。そうすると、該容器１２１ａ内部のＴＴＩＰの一部がガス化される。また、後述のキャリアガスと混合されて、容器１２１ａの気相部分はキャリアガスとガス化したＴＴＩＰにより、飽和された状態になる。
　符号１２３ａはＴＴＩＰのキャリアガス供給源で、例えば、水素ガスあるいはアルゴンガス等のボンベが用いられる。符号１２４ａはＴＴＩＰのキャリアガスの流量計で、所要のガス流量を制御することができる。
　符号１２５ａは、ＴＴＩＰのキャリアガスの供給管で、ＴＴＩＰのキャリアガス供給源１２３ａからのキャリアガスをＴＴＩＰの容器１２１ａに供給する。
　符号１２６ａは、酸化チタンの原料ガスの供給管で、ＴＴＩＰの容器１２１ａで発生したＴＴＩＰガスとキャリアガスの混合ガスを、原料ガス供給部１３２を介してガス混合箱１０５に供給する。
　符号１３１ａは、ガス流量調整装置で、上記ＴＴＩＰガスとキャリアガスの混合ガスの流量を所要の流量に制御することができる。ガス流量調整装置１３１ａは、容器１２１ａ内の液体有機金属がキャリアガスでバブリングされ、その結果、発生した該有機金属で飽和したキャリアガスの流量を調整する。
　ＴＴＩＰの容器１２１ａに流入するキャリアガスの圧力は、例えば１気圧に設定されており、かつ、図示しない圧力センサーで監視されている。また、ＴＴＩＰの容器１２１ａから流出する該有機金属で飽和したキャリアガスの圧力は、図示しない圧力センサーで監視されている。そして、ＴＴＩＰの容器１２１ａの出口側の圧力がキャリアガスの供給圧力を超えた場合には、キャリアガスの供給管１２５ａに設置されている図示しない弁と図示しない制御装置が自動的に稼動して、有機金属の逆流が防止される。
　符号１２７ａはヒータで、酸化チタンの原料ガスの供給管１２６ａの内部を流れるＴＴＩＰガスとキャリアガスの混合ガスが凝縮しないように、ＴＴＩＰ温度調整装置１２２ａより、１０～３０℃高く、例えば９０℃に保持する。
　符号１３３ａは流路開閉弁で、開の場合は、原料ガスの供給管１２６ａ内部を流れる原料ガスを、下流側にある原料ガス供給部１３２を介して、ガス混合箱１０５に、供給する。流路開閉弁１３３ａが閉の場合は、原料ガスの供給管１２６ａ内部を流れる原料ガスを、図示しない排気ラインの方へ排出する。 In FIG. 2, reference numeral 120a denotes TTIP, which is a raw material for the titanium oxide film. Reference numeral 121a denotes a TTIP container, which is used in combination with a TTIP temperature adjusting device 122a described later. Reference numeral 122a denotes a TTIP temperature adjusting device, which maintains the temperature of the TTIP container 121a at an arbitrary temperature in the range of 65 to 90 ° C, for example, 70 ° C. Then, a part of TTIP inside the container 121a is gasified. Further, when mixed with a carrier gas described later, the gas phase portion of the container 121a is saturated by the carrier gas and gasified TTIP.
Reference numeral 123a is a carrier gas supply source of TTIP, and for example, a cylinder such as hydrogen gas or argon gas is used. Reference numeral 124a is a TTIP carrier gas flow meter, which can control a required gas flow rate.
Reference numeral 125a denotes a TTIP carrier gas supply pipe for supplying the carrier gas from the TTIP carrier gas supply source 123a to the TTIP container 121a.
Reference numeral 126 a is a titanium oxide source gas supply pipe, which supplies a mixed gas of TTIP gas and carrier gas generated in the TTIP container 121 a to the gas mixing box 105 via the source gas supply unit 132.
Reference numeral 131a denotes a gas flow rate adjusting device that can control the flow rate of the mixed gas of the TTIP gas and the carrier gas to a required flow rate. The gas flow rate adjusting device 131a adjusts the flow rate of the carrier gas saturated with the generated organic metal as a result of bubbling the liquid organic metal in the container 121a with the carrier gas.
The pressure of the carrier gas flowing into the TTIP container 121a is set to 1 atm, for example, and is monitored by a pressure sensor (not shown). The pressure of the carrier gas saturated with the organic metal flowing out of the TTIP container 121a is monitored by a pressure sensor (not shown). When the pressure on the outlet side of the TTIP container 121a exceeds the supply pressure of the carrier gas, a valve (not shown) installed in the carrier gas supply pipe 125a and a control device (not shown) are automatically operated. , Organic metal backflow is prevented.
Reference numeral 127a denotes a heater, which is 10 to 30 ° C. higher than the TTIP temperature adjusting device 122a, for example, 90 ° C. so that the mixed gas of the TTIP gas and the carrier gas flowing inside the titanium oxide source gas supply pipe 126a does not condense. Hold.
Reference numeral 133a denotes a flow path opening / closing valve. When opened, the raw material gas flowing in the raw material gas supply pipe 126a is supplied to the gas mixing box 105 via the raw material gas supply unit 132 on the downstream side. When the flow path opening / closing valve 133a is closed, the source gas flowing inside the source gas supply pipe 126a is discharged toward an exhaust line (not shown).
　なお、ここでは、酸化チタン膜の原料（ＴＴＩＰ）１２０ａ、ＴＴＩＰの容器１２１ａ、ＴＴＩＰ温度調整装置１２２ａ、ＴＴＩＰのキャリアガス供給源１２３ａ、ＴＴＩＰのキャリアガスの流量計１２４ａ、ガス流量調整装置１３１ａ及び酸化チタンの原料ガスの供給管１２６ａ等で構成される有機金属材料の供給装置を、酸化チタン膜の原料（ＴＴＩＰ）供給装置と呼ぶ。 Here, the raw material (TTIP) 120a of the titanium oxide film, the TTIP container 121a, the TTIP temperature adjustment device 122a, the TTIP carrier gas supply source 123a, the TTIP carrier gas flow meter 124a, the gas flow rate adjustment device 131a, and the oxidation An organometallic material supply device including the titanium source gas supply pipe 126a and the like is referred to as a titanium oxide film material (TTIP) supply device.
　図２において、符号１２８は酸素ガス供給源で、例えば酸素のボンベが用いられる。符号１２９は酸素ガスの流量計で、所要のガス流量を制御することができる。
　符号１３０は、酸素ガスの供給管で、酸素ガス供給源１２８からのガスをガス混合箱１０５に供給する。
　なお、ここでは、酸素ガス供給源１２８、酸素ガスの流量計１２９及び酸素ガスの供給管１３０で構成されるガス供給装置を、酸素ガス供給装置と呼ぶ。 In FIG. 2, reference numeral 128 denotes an oxygen gas supply source, for example, an oxygen cylinder. Reference numeral 129 is an oxygen gas flow meter which can control a required gas flow rate.
Reference numeral 130 denotes an oxygen gas supply pipe for supplying the gas from the oxygen gas supply source 128 to the gas mixing box 105.
Here, the gas supply device including the oxygen gas supply source 128, the oxygen gas flow meter 129, and the oxygen gas supply pipe 130 is referred to as an oxygen gas supply device.
　図２において、真空容器１００内の圧力は、図示しない圧力計によりモニターされる。そして、真空容器１００内の圧力は、上記流量計１２４ａ、１３１ａ及び１２９を所定の値に調整することにより、また、図示しない真空ポンプの排気量を自動的に所定の値に調整することにより、所要の圧力に設定される。
　本第１の実施形態の場合は、キャリアガスとＴＴＩＰガスとの混合ガス、及び酸素ガスの合計流量が、５００ｓｃｃｍ～２０００ｓｃｃｍ程度の場合、圧力０．０１Ｔｏｒｒ～１０Ｔｏｒｒ（１．３３Ｐａ～１３３０Ｐａ）程度に調整できる。
　なお、ここでは、上記図示しない圧力計、流量計１２４ｂ、１３１ｂ、１２４ｃ、１３１ｃ、１２９、及び図示しない真空ポンプ１３２ａ、１３２ｂにより圧力を調整する装置を、圧力調整装置と呼ぶ。
　真空容器１の真空到達圧力は２～３Ｅ－７Ｔｏｒｒ（２．６６～３．９９Ｅ－５Ｐａ）程度である。 In FIG. 2, the pressure in the vacuum vessel 100 is monitored by a pressure gauge (not shown). The pressure in the vacuum vessel 100 is adjusted by adjusting the flow meters 124a, 131a and 129 to a predetermined value, and by automatically adjusting the exhaust amount of a vacuum pump (not shown) to a predetermined value. Set to the required pressure.
In the case of the first embodiment, when the total flow rate of the mixed gas of the carrier gas and the TTIP gas and the oxygen gas is about 500 sccm to 2000 sccm, the pressure is about 0.01 Torr to 10 Torr (1.33 Pa to 1330 Pa). Can be adjusted.
Here, the above-described pressure gauge, flow meters 124b, 131b, 124c, 131c, and 129, and the device that adjusts the pressure by vacuum pumps 132a and 132b (not shown) are referred to as a pressure regulator.
The vacuum ultimate pressure of the vacuum vessel 1 is about 2 to 3E-7 Torr (2.66 to 3.99E-5 Pa).
　図２において、符号１３５は発信器で、高周波数帯域の、例えば１３．５６ＭＨｚの正弦波信号を発生する。符合１３６は信号分配器で、発信器１３６の信号を２つに分岐する。符号１３７は位相調整装置で、正弦波信号の位相を調整する。なお、ここで用いる位相調整装置１３７は、例えば、位相を±１８０度の範囲で、進める、あるいは遅らすことが可能な機能を有する。
　符号１３８ａ、１３８ｂは、それぞれ、第１及び第２の電力増幅器で、入力された信号を増幅する機能を有する。なお、本装置の出力は、数１００Ｗ～１０ＫＷの範囲で、任意に調整可能である。
　第１及び第２の電力増幅器１３８ａ、１３８ｂの出力を、それぞれ、Ｗ１１（ｔ）、Ｗ１２（ｔ）とおくと、次のように表される。
　Ｗ１１（ｔ）＝Ａｓｉｎ（ωｔ＋θ１）
　Ｗ１２（ｔ）＝Ａｓｉｎ（ωｔ＋θ２）
ただし、Ａは振幅、ωは角周波数、ｔは時間、θ１、θ２は初期位相である。 In FIG. 2, reference numeral 135 denotes a transmitter, which generates a sine wave signal of a high frequency band, for example, 13.56 MHz. Reference numeral 136 denotes a signal distributor which branches the signal from the transmitter 136 into two. Reference numeral 137 denotes a phase adjusting device that adjusts the phase of the sine wave signal. Note that the phase adjustment device 137 used here has a function capable of advancing or delaying the phase within a range of ± 180 degrees, for example.
Reference numerals 138a and 138b respectively have a function of amplifying an input signal by the first and second power amplifiers. The output of this apparatus can be arbitrarily adjusted in the range of several hundred W to 10 KW.
When the outputs of the first and second power amplifiers 138a and 138b are respectively W 11 (t) and W 12 (t), they are expressed as follows.
W 11 (t) = Asin (ωt + θ 1 )
W 12 (t) = Asin (ωt + θ 2 )
However, A is an amplitude, ω is an angular frequency, t is time, and θ 1 and θ 2 are initial phases.
　図２において、符号１３９ａ、１３９ｂは、それぞれ、第１及び第２の整合器で、第１及び第２の増幅器１３８ａ、１３８ｂの出力が一対の電極１０１、１０３間に生成されるプラズマに効率よく伝送されるように、出力インピーダンスを調整する。即ち、第１の整合器１３９ａは、第１の増幅１３８ａの出力インピーダンスと、その負荷である一対の電極１０１、１０３間に生成されるプラズマのインピーダンスの整合調整をする。また、第２の整合器１３９ｂは、第２の増幅１３８ｂの出力インピーダンスと、その負荷である一対の電極１０１、１０３間に生成されるプラズマのインピーダンスの整合調整をする。
　符号１４０ａは第１の同軸ケーブルで、後述の第１の電流導入端子１４１ａ、第３の同軸ケーブル１４２ａ及び第１の芯線１４３ａを介して、第１の接続導体１１５ａと第３の接続導体１１６ａとともに、第１の増幅器１３８ａの出力を第１及び第３の給電点１１０ａ、１１１ａに供給する。
　符号１４１ａは真空容器１００の壁に取り付けられた第１の電流導入端子で、真空容器の気密を保持して、第１の同軸ケーブル１４０ａと第３の同軸ケーブル１４２ａを接続する。
　符号１４０ｂは第２の同軸ケーブルで、後述の第２の電流導入端子１４１ｂ、第４の同軸ケーブル１４２ｂ及び第２の芯線１４３ｂを介して、第２の接続導体１１５ｂと第４の接続導体１１６ｂとともに、第２の増幅器１３８ｂの出力を第２及び第４の給電点１１０ｂ、１１１ｂに供給する。
　符号１４１ｂは真空容器１００の壁に取り付けられた第２の電流導入端子で、真空容器の気密を保持して、第２の同軸ケーブル１４０ｂと第４の同軸ケーブル１４２ｂを接続する。 In FIG. 2, reference numerals 139a and 139b denote first and second matching units, respectively, and the outputs of the first and second amplifiers 138a and 138b are efficiently used for the plasma generated between the pair of electrodes 101 and 103. Adjust the output impedance to be transmitted. That is, the first matching device 139a adjusts the output impedance of the first amplifier 138a and the impedance of the plasma generated between the pair of electrodes 101 and 103 that are the loads. The second matching unit 139b adjusts and matches the output impedance of the second amplifier 138b and the impedance of the plasma generated between the pair of electrodes 101 and 103 serving as the load.
Reference numeral 140a denotes a first coaxial cable, together with a first connection conductor 115a and a third connection conductor 116a, through a first current introduction terminal 141a, a third coaxial cable 142a, and a first core wire 143a, which will be described later. The output of the first amplifier 138a is supplied to the first and third feeding points 110a and 111a.
Reference numeral 141a denotes a first current introduction terminal attached to the wall of the vacuum vessel 100, which keeps the vacuum vessel airtight and connects the first coaxial cable 140a and the third coaxial cable 142a.
Reference numeral 140b denotes a second coaxial cable, together with a second connection conductor 115b and a fourth connection conductor 116b, through a second current introduction terminal 141b, a fourth coaxial cable 142b, and a second core wire 143b, which will be described later. The output of the second amplifier 138b is supplied to the second and fourth feeding points 110b and 111b.
Reference numeral 141b denotes a second current introduction terminal attached to the wall of the vacuum vessel 100, which keeps the vacuum vessel airtight and connects the second coaxial cable 140b and the fourth coaxial cable 142b.
　ここで、上記第１の増幅器１３８ａの機能について、補足説明をする。第１の増幅器１３８ａには、図示しない出力値（進行波）のモニター及び下流側から反射して戻ってくる反射波のモニターが付属している。また、該反射波による該第１の電力増幅器１３８ａ本体の電気回路を防護するためのアイソレータが付属されている。
　インピーダンスの調整は次のように行う。即ち、第１の増幅器１３８ａに付属した進行波Ｐｆ及び反射波Ｐｒの検出器を見ながら、第１の整合器１３９ａのリアクタンス（ＬとＣ）を調整する。第１の整合器１３９ａのリアクタンス（ＬとＣ）を調整しながら、上記反射波Ｐｒが最小値になる条件を選定する。そして、第１の増幅器１３８ａの出力を所要の数値に設定して、その出力で、再度、第１の整合器１３９ａのリアクタンス（ＬとＣ）を調整しながら、反射波Ｐｒが最小値になる条件を選ぶ。
　なお、この整合器の調整、即ち、反射波Ｐｒが最小値になる条件は、プラズマ生成条件を変更しない限り変化はないので、特に多くの時間を必要とはしない。 Here, the function of the first amplifier 138a will be supplementarily described. The first amplifier 138a is accompanied by a monitor of an output value (traveling wave) (not shown) and a monitor of a reflected wave that returns from the downstream side. Further, an isolator for protecting the electric circuit of the main body of the first power amplifier 138a by the reflected wave is attached.
The impedance is adjusted as follows. That is, the reactance (L and C) of the first matching unit 139a is adjusted while observing the traveling wave Pf and reflected wave Pr detectors attached to the first amplifier 138a. While adjusting the reactance (L and C) of the first matching unit 139a, a condition is selected in which the reflected wave Pr becomes the minimum value. Then, the output of the first amplifier 138a is set to a required value, and the reflected wave Pr becomes the minimum value while adjusting the reactance (L and C) of the first matching device 139a again with the output. Select conditions.
It should be noted that the adjustment of the matching unit, that is, the condition under which the reflected wave Pr becomes the minimum value does not change unless the plasma generation condition is changed, and therefore does not require much time.
　上記第２の増幅器１３８ｂの機能について、補足説明をする。第２の増幅器１３８ｂには、図示しない出力値（進行波）のモニター及び下流側から反射して戻ってくる反射波のモニターが付属している。また、該反射波による該第２の電力増幅器１３８ｂ本体の電気回路を防護するためのアイソレータが付属されている。
　インピーダンスの調整は次のように行う。即ち、第２の増幅器１３８ｂに付属した進行波Ｐｆ及び反射波Ｐｒの検出器を見ながら、第２の整合器１３９ｂのリアクタンス（ＬとＣ）を調整する。第２の整合器１３９ｂのリアクタンス（ＬとＣ）を調整しながら、上記反射波Ｐｒが最小値になる条件を選定する。そして、第２の増幅器１３８ｂの出力を所要の数値に設定して、その出力で、再度、第２の整合器１３９ｂのリアクタンス（ＬとＣ）を調整しながら、反射波Ｐｒが最小値になる条件を選ぶ。
　なお、この整合器の調整、即ち、反射波Ｐｒが最小値になる条件は、プラズマ生成条件を変更しない限り変化はないので、特に多くの時間を必要とはしない。 The function of the second amplifier 138b will be supplementarily described. The second amplifier 138b is attached with a monitor of an output value (traveling wave) (not shown) and a monitor of a reflected wave that is reflected and returned from the downstream side. Further, an isolator for protecting the electric circuit of the second power amplifier 138b main body due to the reflected wave is attached.
The impedance is adjusted as follows. That is, the reactance (L and C) of the second matching unit 139b is adjusted while observing the traveling wave Pf and reflected wave Pr detectors attached to the second amplifier 138b. While adjusting the reactance (L and C) of the second matching unit 139b, a condition is selected in which the reflected wave Pr becomes a minimum value. Then, the output of the second amplifier 138b is set to a required value, and the reflected wave Pr becomes the minimum value while adjusting the reactance (L and C) of the second matching device 139b again with the output. Select conditions.
It should be noted that the adjustment of the matching unit, that is, the condition under which the reflected wave Pr becomes the minimum value does not change unless the plasma generation condition is changed, and therefore does not require much time.
　次に、本発明の第１の実施形態に係わる薄膜太陽電池用基板を製造するために用いられる酸化亜鉛（ＺｎＯ）膜製造用の高周波プラズマＣＶＤ装置の構成について、説明する。 Next, the configuration of a high-frequency plasma CVD apparatus for producing a zinc oxide (ZnO) film used for producing the thin film solar cell substrate according to the first embodiment of the present invention will be described.
　図３において、符号１２０ｂは酸化亜鉛膜の原料で、例えば、トリメチル亜鉛（ＣＨ３）３Ｚｎ、トリエチル亜鉛（Ｃ２Ｈ５）３Ｚｎ、あるいはジエチル亜鉛（Ｃ２Ｈ５）２Ｚｎなどである。ここでは、トリメチル亜鉛（ＣＨ３）３Ｚｎを用いる。
　符号１２１ｂは酸化亜鉛膜の原料の容器で、その原料の温度調整装置１２２ｂと組み合わせて用いられる。温度調整装置１２２ｂは、容器１２１ｂの温度を、５５～８０℃の範囲の任意の温度、例えば６５℃に保持する。そうすると、該容器１２１ｂ内部の酸化亜鉛膜の原料の一部がガス化される。また、後述のキャリアガスと混合されて、容器１２１ｂの気相部分はキャリアガスとガス化した酸化亜鉛膜の原料により、飽和された状態になる。
　符号１２３ｂは酸化亜鉛膜の原料のキャリアガス供給源で、例えば、水素ガスあるいはアルゴンガス等のボンベが用いられる。符号１２４ｂは酸化亜鉛膜の原料に混入させるキャリアガスの流量計で、所要のガス流量を制御することができる。
　符号１２５ｂは、酸化亜鉛膜の原料のキャリアガスの供給管で、キャリアガス供給源１２３ｂからのキャリアガスを酸化亜鉛膜の原料の容器１２１ｂに供給する。
　符号１２６ｂは、酸化亜鉛膜の原料の供給管で、容器１２１ｂで発生した酸化亜鉛膜の原料とキャリアガスの混合ガスを、原料ガス供給部１３２を介して、ガス混合箱１０５に供給する。
　符号１２７ｂはヒータで、酸化亜鉛膜の原料の供給管１２６ｂの内部を流れる酸化亜鉛膜の原料ガスとキャリアガスの混合ガスが凝縮しないように、温度調整装置１２２ｂより、１０～３０℃高く、例えば９０℃に保持する。
　符号１３１ｂは、ガス流量調整装置で、酸化亜鉛膜の原料ガスとキャリアガスの混合ガスの流量を所要の流量に制御することができる。
　容器１２１ｂに流入するキャリアガスの圧力は、例えば１気圧に設定されており、かつ、図示しない圧力センサーで監視されている。また、容器１２１ｂから流出する該有機金属で飽和したキャリアガスの圧力は、図示しない圧力センサーで監視されている。そして、容器１２１ｂの出口側の圧力がキャリアガスの供給圧力を超えた場合には、キャリアガスの第１の供給管１２５ｂに設置されている図示しない弁と図示しない制御装置が自動的に稼動して、有機金属の逆流が防止される。 In FIG. 3, reference numeral 120b denotes a raw material for the zinc oxide film, for example, trimethyl zinc (CH 3 ) 3 Zn, triethyl zinc (C 2 H 5 ) 3 Zn, or diethyl zinc (C 2 H 5 ) 2 Zn. . Here, trimethyl zinc (CH 3 ) 3 Zn is used.
Reference numeral 121b denotes a raw material container for the zinc oxide film, which is used in combination with the raw material temperature control device 122b. The temperature adjusting device 122b maintains the temperature of the container 121b at an arbitrary temperature in the range of 55 to 80 ° C., for example, 65 ° C. Then, a part of the raw material for the zinc oxide film inside the container 121b is gasified. Further, when mixed with a carrier gas described later, the gas phase portion of the container 121b is saturated with the carrier gas and the raw material of the gasified zinc oxide film.
Reference numeral 123b is a carrier gas supply source of the raw material for the zinc oxide film, and for example, a cylinder such as hydrogen gas or argon gas is used. Reference numeral 124b is a carrier gas flow meter mixed in the raw material of the zinc oxide film, and the required gas flow rate can be controlled.
Reference numeral 125b denotes a carrier gas supply pipe for the raw material of the zinc oxide film, which supplies the carrier gas from the carrier gas supply source 123b to the raw material container 121b for the zinc oxide film.
Reference numeral 126b denotes a zinc oxide film raw material supply pipe, which supplies the mixed gas of the zinc oxide film raw material and the carrier gas generated in the container 121b to the gas mixing box 105 via the raw material gas supply unit 132.
Reference numeral 127b denotes a heater, which is 10 to 30 ° C. higher than the temperature adjustment device 122b so that the mixed gas of the zinc oxide film source gas and the carrier gas flowing inside the zinc oxide film source supply pipe 126b does not condense. Hold at 90 ° C.
Reference numeral 131b denotes a gas flow rate adjusting device that can control the flow rate of the mixed gas of the raw material gas of the zinc oxide film and the carrier gas to a required flow rate.
The pressure of the carrier gas flowing into the container 121b is set to 1 atm, for example, and is monitored by a pressure sensor (not shown). The pressure of the carrier gas saturated with the organic metal flowing out from the container 121b is monitored by a pressure sensor (not shown). When the pressure on the outlet side of the container 121b exceeds the supply pressure of the carrier gas, a valve (not shown) installed in the carrier gas first supply pipe 125b and a control device (not shown) are automatically operated. Thus, backflow of the organic metal is prevented.
　なお、ここでは、酸化亜鉛膜の原料１２０ｂ、酸化亜鉛膜の原料の容器１２１ｂ、温度調整装置１２２ｂ、酸化亜鉛膜の原料のキャリアガス供給源１２３ｂ、酸化亜鉛膜の原料のキャリアガスの供給管１２４ｂ、ガス流量調整装置１３１ｂ及び酸化亜鉛膜の原料の供給管１２６ｂなどで構成される有機金属材料の供給装置を、酸化亜鉛膜の原料供給装置と呼ぶ。 Here, the zinc oxide film raw material 120b, the zinc oxide film raw material container 121b, the temperature adjusting device 122b, the zinc oxide film raw material carrier gas supply source 123b, and the zinc oxide film raw material carrier gas supply pipe 124b. An organometallic material supply device including the gas flow rate adjusting device 131b and the zinc oxide film material supply pipe 126b is referred to as a zinc oxide film material supply device.
　図３において、符号１２０ｃは酸化亜鉛膜のドーピング材料で、例えば、トリメチルガリウム（ＣＨ３）３Ｇａ、トリエチルガリウム（Ｃ２Ｈ５）３Ｇａ、トリメチルアルミニウム（ＣＨ３）３Ａｌ、及びトリエチルアルミニウム（Ｃ２Ｈ５）３Ａｌなどである。ここでは、トリメチルガリウム（ＣＨ３）３Ｇａを用いる。
　符号１２１ｃは上記ドーピング材料の容器で、その材料の温度調整装置１２２ｃと組み合わせて用いられる。温度調整装置１２２ｃは、容器１２１ｃの温度を、６０～９０℃の範囲の任意の温度、例えば７０℃に保持する。そうすると、該容器１２１ｃ内部のドーピング材料の一部がガス化される。また、後述のキャリアガスと混合されて、容器１２１ｃの気相部分はキャリアガスとガス化したドーピング材料により、飽和された状態になる。
　符号１２３ｃはドーピング材料のキャリアガス供給源で、例えば、水素ガス
あるいはアルゴンガス等のボンベが用いられる。符号１２４ｃはキャリアガスの流量計で、所要のガス流量を制御することができる。
　符号１２５ｃは、ドーピング材料のキャリアガスの供給管で、キャリアガス供給源１２３ｃからのキャリアガスをドーピング材料の容器１２１ｃに供給する。
　符号１２６ｃは、ドーピング材料とキャリアガスの混合ガスの供給管で、容器１２１ｃで発生した酸化ドーピング材料ガスとキャリアガスの混合ガスを、
原料ガス供給部１３２を介して、ガス混合箱１０５に供給する。
　符号１２７ｃはヒータでドーピング材料ガスの供給管１２６ｃの内部を流れるドーピング材料ガスとキャリアガスの混合ガスが凝縮しないように、温度調整装置１２２ｃより、１０～３０℃高く、例えば９０℃に保持する。
　符号１３１ｃは、ガス流量調整装置で、ドーピング材料ガスとキャリアガスの混合ガスの流量を所要の流量に制御することができる。
　容器１２１ｃに流入するキャリアガスの圧力は、例えば１気圧に設定されており、かつ、図示しない圧力センサーで監視されている。また、容器１２１ｃから流出する該有機金属で飽和したキャリアガスの圧力は、図示しない圧力センサーで監視されている。そして、容器１２１ｃの出口側の圧力がキャリアガスの供給圧力を超えた場合には、キャリアガスの第１の供給管１２５ｃに設置されている図示しない弁と図示しない制御装置が自動的に稼動して、有機金属の逆流が防止される。 In FIG. 3, reference numeral 120c denotes a doping material for a zinc oxide film. For example, trimethylgallium (CH 3 ) 3 Ga, triethylgallium (C 2 H 5 ) 3 Ga, trimethylaluminum (CH 3 ) 3 Al, and triethylaluminum ( C 2 H 5 ) 3 Al. Here, trimethylgallium (CH 3 ) 3 Ga is used.
Reference numeral 121c denotes a container for the doping material, which is used in combination with the temperature adjusting device 122c for the material. The temperature adjusting device 122c maintains the temperature of the container 121c at an arbitrary temperature within the range of 60 to 90 ° C., for example, 70 ° C. Then, a part of the doping material inside the container 121c is gasified. Further, when mixed with a carrier gas described later, the gas phase portion of the container 121c is saturated with the carrier gas and the gasified doping material.
Reference numeral 123c denotes a carrier gas supply source of a doping material. For example, a cylinder such as hydrogen gas or argon gas is used. Reference numeral 124c is a carrier gas flow meter, which can control a required gas flow rate.
Reference numeral 125c is a doping material carrier gas supply pipe for supplying the carrier gas from the carrier gas supply source 123c to the doping material container 121c.
Reference numeral 126c is a supply pipe for a mixed gas of a doping material and a carrier gas, and the mixed gas of an oxidizing doping material gas and a carrier gas generated in the container 121c.
The gas is supplied to the gas mixing box 105 via the source gas supply unit 132.
Reference numeral 127c is a heater, and is maintained at 10 to 30 ° C., for example, 90 ° C. higher than the temperature adjusting device 122c so that the mixed gas of the doping material gas and the carrier gas flowing inside the doping material gas supply pipe 126c does not condense.
Reference numeral 131c denotes a gas flow rate adjusting device that can control the flow rate of the mixed gas of the doping material gas and the carrier gas to a required flow rate.
The pressure of the carrier gas flowing into the container 121c is set to 1 atm, for example, and is monitored by a pressure sensor (not shown). The pressure of the carrier gas saturated with the organic metal flowing out from the container 121c is monitored by a pressure sensor (not shown). When the pressure on the outlet side of the container 121c exceeds the supply pressure of the carrier gas, a valve (not shown) installed in the carrier gas first supply pipe 125c and a control device (not shown) are automatically operated. Thus, backflow of the organic metal is prevented.
　なお、ここでは、ドーピング材料１２０ｃ、ドーピング材料の容器１２１ｃ、温度調整装置１２２ｃ、キャリアガス供給源１２３ｃ、流量計１２４ｃ、キャリアガスの供給管１２５ｃ、ガス流量調整装置１３１ｃ及びドーピング材料とキャリアガスの混合ガスの供給管１２６ｃ等から構成される有機金属材料の供給装置を、酸化亜鉛膜のドーピング材料供給装置と呼ぶ。 Here, doping material 120c, doping material container 121c, temperature adjusting device 122c, carrier gas supply source 123c, flow meter 124c, carrier gas supply pipe 125c, gas flow rate adjusting device 131c, and mixing of doping material and carrier gas An organometallic material supply device including the gas supply pipe 126c is referred to as a zinc oxide film doping material supply device.
　符号１３３ｂは流路開閉弁で、開の場合は、原料ガスの供給管１２６ｂ、１２６ｃの内部を流れる有機金属の原料ガス及びドーピングガスを、下流側にある原料ガス供給部１３２を介して、ガス混合箱１０５に供給する。流路開閉弁１３３ｂが閉の場合は、原料ガスの供給管１２６ｂ、１２６ｃの内部を流れる有機金属原料ガスを、図示しない排気ラインの方へ排出する。 Reference numeral 133b denotes a flow path opening / closing valve, and when opened, the organic metal source gas and doping gas flowing in the source gas supply pipes 126b and 126c are passed through the source gas supply unit 132 on the downstream side. Supply to the mixing box 105. When the flow path opening / closing valve 133b is closed, the organometallic source gas flowing in the source gas supply pipes 126b and 126c is discharged toward an exhaust line (not shown).
　図３において、真空容器１００内の圧力は、図示しない圧力計によりモニターされる。そして、真空容器１００内の圧力は、上記流量計１２４ｂ、１３１ｂ、１２４ｃ、１３１ｃ、及び１２９を所定の値に調整することにより、また、図示しない真空ポンプの排気量を自動的に所定の値に調整することにより、所要の圧力に設定される。
　本発明の第１の実施形態の場合は、酸化亜鉛膜の原料ガス、ドーピング材料ガス、キャリアガス、及び酸素ガスの合計流量が、５００ｓｃｃｍ～２０００ｓｃｃｍ程度の場合、圧力０．０１Ｔｏｒｒ～１０Ｔｏｒｒ（１．３３Ｐａ～１３３０Ｐａ）程度に調整できる。
　なお、ここでは、上記図示しない圧力計、流量計１２４ｂ、１３１ｂ、１２４ｃ、１３１ｃ、１２９、及び図示しない真空ポンプ１３２ａ、１３２ｂにより圧力を調整する装置を、圧力調整装置と呼ぶ。
　真空容器１の真空到達圧力は２～３Ｅ－７Ｔｏｒｒ（２．６６～３．９９Ｅ－５Ｐａ）程度である。 In FIG. 3, the pressure in the vacuum vessel 100 is monitored by a pressure gauge (not shown). The pressure in the vacuum vessel 100 is adjusted to a predetermined value by adjusting the flow meters 124b, 131b, 124c, 131c, and 129, and the exhaust amount of a vacuum pump (not shown) is automatically set to a predetermined value. By adjusting, the required pressure is set.
In the case of the first embodiment of the present invention, when the total flow rate of the source gas of the zinc oxide film, the doping material gas, the carrier gas, and the oxygen gas is about 500 sccm to 2000 sccm, the pressure is 0.01 Torr to 10 Torr (1. 33 Pa to 1330 Pa).
Here, the above-described pressure gauge, flow meters 124b, 131b, 124c, 131c, and 129, and the device that adjusts the pressure by vacuum pumps 132a and 132b (not shown) are referred to as a pressure regulator.
The vacuum ultimate pressure of the vacuum vessel 1 is about 2 to 3E-7 Torr (2.66 to 3.99E-5 Pa).
　次に、上記構成の高周波プラズマ表面処理装置を用いて、本発明の第１の実施形態に係わる薄膜太陽電池用基板を製造する方法を説明する。
　ここで説明する方法は、非晶質酸化チタン膜、結晶質酸化チタン膜及び結晶質酸化亜鉛膜のそれぞれの製膜条件とその条件における製膜速度の把握に必要な予備製膜試験（予備製膜工程）と、該製膜条件に基づいて薄膜太陽電池用基板を製造する製膜試験（製造工程）の２つの工程から成る製造方法である。 Next, a method for manufacturing a thin-film solar cell substrate according to the first embodiment of the present invention using the high-frequency plasma surface treatment apparatus having the above configuration will be described.
The method described here is a preliminary film formation test (preliminary production) required for grasping the film forming conditions of each of the amorphous titanium oxide film, the crystalline titanium oxide film, and the crystalline zinc oxide film and the film forming speed under those conditions. A film forming process) and a film forming test (manufacturing process) for manufacturing a thin film solar cell substrate based on the film forming conditions.
　先ず、非晶質酸化チタン膜及び結晶質酸化チタン膜の予備製膜試験（予備製膜工程）について説明する。 First, a preliminary film forming test (preliminary film forming process) of an amorphous titanium oxide film and a crystalline titanium oxide film will be described.
　図２において、予め、基板１０８として、サイズ１．５ｍｘ０．２５ｍｘ厚み４ｍｍのガラスを基板リフター１１２及び図示しない基板搬入出ゲート１１８を用いて、第２の電極１０３上に設置する。
　そして、図示しない基板ヒータ１０２により、基板１０８の温度を、５０～４５０℃の範囲に、例えば２００℃に設定する。
　そして、図示しない真空ポンプを稼動させ、真空容器１内の不純物ガス等を除去する。
　また、真空容器１００内の圧力を、上記圧力調整装置により、０．０１Ｔｏｒｒ～１Ｔｏｒｒ（１．３３Ｐａ～１３３Ｐａ）の範囲、例えば０．０５Ｔｏｒｒ（６．６５Ｐａ）に設定する。
　また、予め、流路開閉弁１３３ａを閉とし、上流側から供給されるキャリアガスとＴＴＩＰガスの混合ガスを排気ラインに排気できる状態において、上記酸化チタン膜の原料（ＴＴＩＰ）供給装置において、ＴＴＩＰ温度調整装置１２２ａによりＴＴＩＰの容器１２１ａ及び酸化チタン膜の原料（ＴＴＩＰ）１２０ａの温度を７０～９０℃に、例えば７０℃に設定し、ＴＴＩＰのキャリアガス供給源１２３ａから供給されるアルゴンガスを、ＴＴＩＰのキャリアガスの流量計１２４ａで、３００～８００ｓｃｃｍに、例えば４００ｓｃｃｍ設定する。また、ガス流量調整装置１３１ａの流量を８００ｓｃｃｍに設定する。
　そうすると、ＴＴＩＰの容器１２１ａの中で、ＴＴＩＰ原料はキャリアガスのアルゴンガスによりバブリングされて、気化する。その気化したＴＴＩＰ原料とアルゴンガスの混合ガスは、上記ガス流量調整装置１３１ａを介して、流路開閉弁１３３ａの方へ供給される。
　また、予め、原料ガス温度調整装置１０９により、ガス混合箱１０５及び第１の電極１０１の温度を、８０～１００℃に、例えば９０℃に設定する。
　そして、上記酸素ガス供給装置の流量計１２９の流量を、３００～８００ｓｃｃｍ、例えば４００ｓｃｃｍに設定する。そうすると、酸素ガスの供給管１３０からガス混合器１０５に流量４００ｓｃｃｍの酸素が供給される。 In FIG. 2, glass having a size of 1.5 mx 0.25 mx 4 mm in thickness is previously placed on the second electrode 103 as a substrate 108 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown).
Then, the substrate heater 102 (not shown) sets the temperature of the substrate 108 in a range of 50 to 450 ° C., for example, 200 ° C.
And the vacuum pump which is not illustrated is operated and the impurity gas etc. in the vacuum vessel 1 are removed.
Further, the pressure in the vacuum vessel 100 is set in the range of 0.01 Torr to 1 Torr (1.33 Pa to 133 Pa), for example, 0.05 Torr (6.65 Pa) by the pressure adjusting device.
In the state where the channel opening / closing valve 133a is closed in advance and the mixed gas of the carrier gas and the TTIP gas supplied from the upstream side can be exhausted to the exhaust line, in the titanium oxide film raw material (TTIP) supply device, The temperature of the TTIP container 121a and the titanium oxide film material (TTIP) 120a is set to 70 to 90 ° C., for example, 70 ° C. by the temperature adjusting device 122a, and argon gas supplied from the TTIP carrier gas supply source 123a is used. For example, 400 sccm is set to 300 to 800 sccm with the flowmeter 124a of the carrier gas of TTIP. Further, the flow rate of the gas flow rate adjusting device 131a is set to 800 sccm.
Then, in the TTIP container 121a, the TTIP raw material is bubbled with the argon gas as the carrier gas and vaporized. The vaporized mixed gas of TTIP raw material and argon gas is supplied to the flow path opening / closing valve 133a via the gas flow rate adjusting device 131a.
Further, the temperature of the gas mixing box 105 and the first electrode 101 is previously set to 80 to 100 ° C., for example, 90 ° C. by the source gas temperature adjusting device 109.
Then, the flow rate of the flow meter 129 of the oxygen gas supply device is set to 300 to 800 sccm, for example, 400 sccm. Then, oxygen at a flow rate of 400 sccm is supplied from the oxygen gas supply pipe 130 to the gas mixer 105.
　次に、発信器１３５から、例えば周波数１３．５６ＭＨｚの正弦波を発生させて、その信号を分配器１３６で２つに分けて、その一方は、位相調整装置１３７を介して第１の電力増幅器１３８ａで電力増幅され、第１のインピーダンス整合器１３９ａ、第１の同軸ケーブル１４０ａ、第１の電流導入端子１４１ａ、第１の芯線１４３ａ等を用いて、第１及び第３の給電点１１０ａ、１１１ａに供給される。他方の信号は、第２の電力増幅器１３８ｂで電力増幅され、第２のインピーダンス整合器１３９ｂ、第２の同軸ケーブル１４０ｂ、第２の電流導入端子１４１ｂ、第２の芯線１４３ｂ等を用いて、第２及び第４の給電点１１０ｂ、１１１ｂに供給される。
　第１及び第２の電力増幅器１３８ａ、１３８ｂの出力は、０．５～２ＫＷの範囲で、例えば１．５ＫＷに設定する。
　供給される２つの電力により発生する、一対の電極間のプラズマの強さは、以下に示す電力の強さの分布に比例したものになる。
　即ち、第１及び第３の給電点１１０ａ、１１１ａ間には次式で表される電力Ｗ１１（ｔ）が、第２及び第４の給電点１１０ｂ、１１１ｂ間には次式で表される電力Ｗ１２（ｔ）が供給される。
　Ｗ１１（ｔ）＝Ａｓｉｎ（ωｔ＋θ１）
　Ｗ１２（ｔ）＝Ａｓｉｎ（ωｔ＋θ２）
ただし、Ａは振幅、ωは角周波数、ｔは時間、θ１、θ２は初期位相である。
　そうすると、一対の電極間の電力の強さは、次式で表されるＩ（ｘ、ｔ）の分布となる。
　　Ｉ（ｘ、ｔ）∝ｃｏｓ２｛２π（ｘ－Ｌ０／２）／λ－Δθ／２｝
ただし、λは電力の波長、Ｌ０は電極の長さ、Δθ＝θ１―θ２である。
　この場合、前記第１のインピーダンス整合器１３９ａ及び第２のインピーダンス整合器１３９ｂを調整することにより、それぞれのインピーダンス整合器１３９ａ、１３９ｂの上流側に上記供給電力の反射波が戻らないようにすることができる。
　また、上記電力の強さの分布は、位相調整装置１３７により位相Δθ＝θ１―θ２を調整することにより、一様に調整できる。
　したがって、一対の電極間に発生するプラズマは、上記Ｉ（ｘ、ｔ）で示される強さに比例した強さの分布を持つ。 Next, a sine wave having a frequency of 13.56 MHz, for example, is generated from the transmitter 135, and the signal is divided into two by a distributor 136, one of which is a first power amplifier via a phase adjustment device 137. The first and third feeding points 110a and 111a are amplified using the first impedance matching unit 139a, the first coaxial cable 140a, the first current introduction terminal 141a, the first core wire 143a, and the like. To be supplied. The other signal is amplified by the second power amplifier 138b, and the second impedance matching unit 139b, the second coaxial cable 140b, the second current introduction terminal 141b, the second core wire 143b, and the like are used. 2 and the fourth feeding points 110b and 111b.
The outputs of the first and second power amplifiers 138a and 138b are set in the range of 0.5 to 2 kW, for example, 1.5 kW.
The intensity of the plasma between the pair of electrodes generated by the two supplied electric powers is proportional to the power intensity distribution shown below.
That is, the power W 11 (t) expressed by the following equation is expressed between the first and third feeding points 110a and 111a, and is expressed by the following equation between the second and fourth feeding points 110b and 111b. Electric power W 12 (t) is supplied.
W 11 (t) = Asin (ωt + θ 1 )
W 12 (t) = Asin (ωt + θ 2 )
However, A is an amplitude, ω is an angular frequency, t is time, and θ 1 and θ 2 are initial phases.
Then, the power intensity between the pair of electrodes has a distribution of I (x, t) expressed by the following equation.
I (x, t) ∝cos 2 {2π (x−L0 / 2) / λ−Δθ / 2}
Here, λ is the wavelength of power, L0 is the length of the electrode, and Δθ = θ 1 −θ 2 .
In this case, by adjusting the first impedance matching unit 139a and the second impedance matching unit 139b, the reflected wave of the supplied power is prevented from returning to the upstream side of the respective impedance matching units 139a and 139b. Can do.
The power intensity distribution can be uniformly adjusted by adjusting the phase Δθ = θ 1 −θ 2 by the phase adjusting device 137.
Therefore, the plasma generated between the pair of electrodes has a strength distribution proportional to the strength indicated by I (x, t).
　上記高周波電力の供給の準備を整えた後、上記流路開閉弁１３３ａを開にする。流路開閉弁１３３ａが開になると、上流側から供給されるキャリアガスとＴＴＩＰガスの混合ガスが原料ガス供給部１３２を介して、ガス混合箱１０５に供給される。そして、酸化チタン膜の原料（ＴＴＩＰ）供給装置から供給されるキャリアガスとＴＴＩＰガスの混合ガス、例えば８００ｓｃｃｍと、酸素ガス供給装置から供給される酸素ガス、例えば４００ｓｃｃｍが、ガスシャワー１０６から一対の電極１０１、１０３間に流出する。
　そうすると、一対の電極１０１、１０３間には、キャリアガスとＴＴＩＰガスと、酸素の混合ガスのプラズマが発生する。キャリアガスとＴＴＩＰガスと酸素の混合ガスがプラズ化されると、プラズマ化学反応により、酸素ラジカルやチタンを含むラジカルが発生する。プラズマ中の各種ラジカルは、拡散現象により濃度の高い方から低い方へ拡散する。
　その結果、ガラス基板上に、例えば、非晶質酸化チタン膜、微結晶酸化チタン膜、あるいは結晶質酸化チタン膜が堆積する。 After preparing for the supply of the high-frequency power, the flow path opening / closing valve 133a is opened. When the flow path opening / closing valve 133a is opened, the mixed gas of the carrier gas and the TTIP gas supplied from the upstream side is supplied to the gas mixing box 105 through the source gas supply unit 132. Then, a mixed gas of carrier gas and TTIP gas supplied from the titanium oxide film raw material (TTIP) supply device, for example, 800 sccm, and oxygen gas supplied from the oxygen gas supply device, for example, 400 sccm, are supplied from the gas shower 106 as a pair. It flows out between the electrodes 101 and 103.
Then, plasma of a mixed gas of carrier gas, TTIP gas, and oxygen is generated between the pair of electrodes 101 and 103. When the mixed gas of carrier gas, TTIP gas, and oxygen is plasmized, oxygen radicals and radicals including titanium are generated by plasma chemical reaction. Various radicals in the plasma diffuse from a higher concentration to a lower concentration due to a diffusion phenomenon.
As a result, for example, an amorphous titanium oxide film, a microcrystalline titanium oxide film, or a crystalline titanium oxide film is deposited on the glass substrate.
　上記の要領で、予備製膜試験（予備製膜工程）として、基板温度、キャリアガスの流量、及び酸素ガスの流量等をパラメータに、製膜時間を例えば１０～３０分間にして、前記基板１０８に酸化チタン膜を形成させる。製膜後、真空容器１００から前記基板１０８を取り出して、製膜された酸化チタン膜の膜質及び膜厚みを評価する。
　膜質の評価には、レーザラマン分光法、走査型電子顕微鏡（ＳＥＭ）、高分解能透過電子顕微鏡（ＴＥＭ）及び二次イオン質量分析法（ＳＩＭＳ）等を用いる。膜厚は、走査型電子顕微鏡（ＳＥＭ）、段差計、あるいは分光エリプソメータで測定する。 In the manner described above, as a preliminary film formation test (preliminary film formation step), the substrate temperature is set to 10 to 30 minutes, for example, with the substrate temperature, the flow rate of the carrier gas, and the flow rate of oxygen gas as parameters. Then, a titanium oxide film is formed. After the film formation, the substrate 108 is taken out from the vacuum vessel 100, and the film quality and film thickness of the formed titanium oxide film are evaluated.
For the evaluation of the film quality, laser Raman spectroscopy, scanning electron microscope (SEM), high resolution transmission electron microscope (TEM), secondary ion mass spectrometry (SIMS), or the like is used. The film thickness is measured with a scanning electron microscope (SEM), a step meter, or a spectroscopic ellipsometer.
　上記予備製膜試験（予備製膜工程）において、基板１０８がガラスで、基板１０８の温度が１００～２５０℃の範囲に設定されれば、ガラス基板１０８に製膜される膜は、すべて、非晶質の酸化チタンになるという結果が得られる。
　即ち、製膜速度は、高周波電力、ＴＴＩＰ原料の流量、キャリアガスの流量、及び圧力に依存するが、製膜される酸化チタン膜の膜質は、図４に示しているように、非晶質になる。
　なお、図４は、横軸に製膜時間を、縦軸に膜厚と膜質をとることにより、製膜条件として下地がガラスで、基板温度が１００～２５０℃の場合に得られる酸化チタン膜の特性を示している。
　非晶質酸化チタンの製膜速度は、上記試験条件の場合、即ち、キャリアガスとＴＴＩＰ原料の混合ガスの流量８００ｓｃｃｍ、酸素ガスの流量４００ｓｃｃｍ、圧力０．０５Ｔｏｒｒ（６．６５Ｐａ）及び高周波電力１．５ＫＷの場合は、１０ｎｍ／分程度が得られる。
　なお、製膜速度は、高周波電力及び原料ガスを増大することにより、改善することが可能である。 In the preliminary film forming test (preliminary film forming step), if the substrate 108 is made of glass and the temperature of the substrate 108 is set in the range of 100 to 250 ° C., all films formed on the glass substrate 108 are non-coated. The result is a crystalline titanium oxide.
That is, the film forming speed depends on the high frequency power, the flow rate of the TTIP raw material, the flow rate of the carrier gas, and the pressure, but the film quality of the formed titanium oxide film is amorphous as shown in FIG. become.
In FIG. 4, the horizontal axis represents the film formation time, and the vertical axis represents the film thickness and film quality, so that the titanium oxide film obtained when the substrate is glass and the substrate temperature is 100 to 250 ° C. as the film formation conditions. The characteristics are shown.
The film formation rate of amorphous titanium oxide is as follows under the above test conditions, that is, the flow rate of the mixed gas of the carrier gas and the TTIP raw material is 800 sccm, the flow rate of oxygen gas is 400 sccm, the pressure is 0.05 Torr (6.65 Pa), and the high frequency power is 1 In the case of .5 KW, about 10 nm / min is obtained.
In addition, the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
　同様に、上記予備製膜試験（予備製膜工程）において、基板１０８がガラスで、基板１０８の温度が２５０～３８０℃の範囲に設定されれば、ガラス基板１０８に製膜される膜は、図５に示しているように、製膜初期の膜厚数１０ｎｍまでは、非晶質の酸化チタンで、その非晶質の酸化チタンの上には、膜厚数１０ｎｍの範囲で、非晶質と微結晶の混相状態の酸化チタンが製膜される。その混相状態の酸化チタンの上には結晶質の酸化チタン膜が製膜される。
　なお、図５は、横軸に製膜時間を、縦軸に膜厚と膜質をとることにより、製膜条件として下地がガラスで、基板温度が２５０～３８０℃の場合に得られる酸化チタン膜の特性を示している。
　結晶質酸化チタンの製膜速度は、上記試験条件の場合、即ち、キャリアガスとＴＴＩＰ原料の混合ガスの流量８００ｓｃｃｍ、酸素ガスの流量４００ｓｃｃｍ、圧力０．０５Ｔｏｒｒ（６．６５Ｐａ）及び高周波電力１．５ＫＷの場合は、１０ｎｍ／分程度が得られる。
　なお、製膜速度は、高周波電力及び原料ガスを増大することにより、改善することが可能である。 Similarly, in the preliminary film forming test (preliminary film forming step), if the substrate 108 is made of glass and the temperature of the substrate 108 is set in the range of 250 to 380 ° C., the film formed on the glass substrate 108 is As shown in FIG. 5, amorphous titanium oxide is used up to a film thickness of several tens of nm at the initial stage of film formation. Amorphous titanium oxide is amorphous over the amorphous titanium oxide in a film thickness of several tens of nm. Titanium oxide in a mixed phase of quality and microcrystal is formed. A crystalline titanium oxide film is formed on the mixed phase titanium oxide.
In FIG. 5, the horizontal axis represents the film formation time and the vertical axis represents the film thickness and film quality, so that the titanium oxide film obtained when the substrate is glass and the substrate temperature is 250 to 380 ° C. as the film formation conditions. The characteristics are shown.
The film formation rate of crystalline titanium oxide is as follows under the above test conditions, that is, a flow rate of 800 sccm of a mixed gas of carrier gas and TTIP raw material, a flow rate of 400 sccm of oxygen gas, a pressure of 0.05 Torr (6.65 Pa), and a high frequency power of 1. In the case of 5 KW, about 10 nm / min is obtained.
In addition, the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
　また、同様に、上記予備製膜試験（予備製膜工程）において、基板１０８がガラスで、基板１０８の温度が３８０～４５０℃の範囲に設定されれば、ガラス基板１０８に製膜される膜は、図６に示しているように、製膜初期の膜厚み３～１０ｎｍまでは、非晶質と微結晶の混相状態の酸化チタンが製膜され、その上には、結晶質の酸化チタンが製膜される。
　なお、図６は、横軸に製膜時間を、縦軸に膜厚と膜質をとることにより、製膜条件として下地がガラスで、基板温度が３８０～４５０℃の場合に得られる酸化チタン膜の特性を示している。
　結晶質酸化チタンの製膜速度は、上記試験条件の場合、即ち、キャリアガスとＴＴＩＰ原料の混合ガスの流量８００ｓｃｃｍ、酸素ガスの流量４００ｓｃｃｍ、圧力０．０５Ｔｏｒｒ（６．６５Ｐａ）及び高周波電力１．５ＫＷの場合は、２０ｎｍ／分程度が得られる。
　なお、製膜速度は、高周波電力及び原料ガスを増大することにより、改善することが可能である。 Similarly, in the preliminary film forming test (preliminary film forming step), if the substrate 108 is made of glass and the temperature of the substrate 108 is set in the range of 380 to 450 ° C., the film formed on the glass substrate 108 As shown in FIG. 6, in the initial film thickness of 3 to 10 nm, a mixed phase of amorphous and microcrystalline titanium oxide is formed, on which crystalline titanium oxide is formed. Is formed.
In FIG. 6, the horizontal axis represents the film formation time and the vertical axis represents the film thickness and film quality, so that the titanium oxide film obtained when the substrate is glass and the substrate temperature is 380 to 450 ° C. as the film formation conditions. The characteristics are shown.
The film formation rate of crystalline titanium oxide is as follows under the above test conditions, that is, a flow rate of 800 sccm of a mixed gas of carrier gas and TTIP raw material, a flow rate of 400 sccm of oxygen gas, a pressure of 0.05 Torr (6.65 Pa), and a high frequency power of 1. In the case of 5 KW, about 20 nm / min is obtained.
In addition, the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
　また、同様に、上記予備製膜試験（予備製膜工程）において、基板１０８がガラスで、その上に、膜厚数ｎｍ～５０ｎｍ程度の非晶質酸化チタン、あるいは、非晶質と微結晶の混相状態の酸化チタン、あるいは、結晶質酸化チタンが製膜され、その上に、基板１０８の温度条件を３５０～４５０℃の範囲に設定して、酸化チタンを製膜すれば、図７に示しているように、結晶質の酸化チタン膜が得られる。
　なお、図７は、横軸に製膜時間を、縦軸に膜厚と膜質をとることにより、製膜条件として下地が非晶質酸化チタン膜、あるいは微結晶酸化チタン膜、あるいは結晶質酸化チタン膜で、基板温度が３５０～４５０℃の場合に得られる酸化チタン膜の特性を示している。
　結晶質酸化チタンの製膜速度は、上記試験条件の場合、即ち、キャリアガスとＴＴＩＰ原料の混合ガスの流量８００ｓｃｃｍ、酸素ガスの流量４００ｓｃｃｍ、圧力０．０５Ｔｏｒｒ（６．６５Ｐａ）及び高周波電力１ＫＷの場合は、２０ｎｍ／分程度が得られる。
　なお、製膜速度は、高周波電力及び原料ガスを増大することにより、改善することが可能である。 Similarly, in the preliminary film-forming test (preliminary film-forming step), the substrate 108 is made of glass, on which amorphous titanium oxide having a film thickness of several nm to 50 nm, or amorphous and microcrystalline 7 is formed by forming the mixed phase titanium oxide or crystalline titanium oxide, and setting the temperature condition of the substrate 108 in the range of 350 to 450 ° C. to form titanium oxide. As shown, a crystalline titanium oxide film is obtained.
In FIG. 7, the horizontal axis indicates the film forming time, and the vertical axis indicates the film thickness and film quality. As a film forming condition, the base is an amorphous titanium oxide film, a microcrystalline titanium oxide film, or a crystalline oxide. The characteristics of the titanium oxide film obtained when the substrate temperature is 350 to 450 ° C. with a titanium film are shown.
The film formation rate of crystalline titanium oxide is as follows under the above test conditions, that is, the flow rate of the mixed gas of the carrier gas and the TTIP raw material is 800 sccm, the flow rate of oxygen gas is 400 sccm, the pressure is 0.05 Torr (6.65 Pa), and the high-frequency power is 1 KW. In the case, about 20 nm / min is obtained.
In addition, the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
　次に、結晶質酸化亜鉛膜の予備製膜試験（予備製膜工程）について説明する。 Next, a preliminary film forming test (preliminary film forming step) of the crystalline zinc oxide film will be described.
　図３において、予め、基板１０８として、該基板表面に結晶質酸化チタン膜が製膜されているサイズ１．５ｍｘ０．２５ｍｘ厚み４ｍｍのガラス基板を基板リフター１１２及び図示しない基板搬入出ゲート１１８を用いて、第２の電極１０３上に設置する。
　そして、図示しない基板ヒータ１０２により、基板１０８の温度を、２００～４５０℃の範囲に、例えば３００℃に設定する。
　そして、図示しない真空ポンプを稼動させ、真空容器１内の不純物ガス等を除去する。
　また、真空容器１００内の圧力を、上記圧力調整装置により、０．０１Ｔｏｒｒ～１Ｔｏｒｒ（１．３３Ｐａ～１３３Ｐａ）の範囲、例えば０．０５Ｔｏｒｒ（６．６５Ｐａ）に設定する。 In FIG. 3, a glass substrate having a size of 1.5 mx 0.25 mx 4 mm in thickness, on which a crystalline titanium oxide film is formed on the surface of the substrate in advance, is used as a substrate 108 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown). And placed on the second electrode 103.
Then, the temperature of the substrate 108 is set in the range of 200 to 450 ° C., for example, 300 ° C. by the substrate heater 102 (not shown).
And the vacuum pump which is not illustrated is operated and the impurity gas etc. in the vacuum vessel 1 are removed.
Further, the pressure in the vacuum vessel 100 is set in the range of 0.01 Torr to 1 Torr (1.33 Pa to 133 Pa), for example, 0.05 Torr (6.65 Pa) by the pressure adjusting device.
　また、図３において、予め、流路開閉弁１３３ｂを閉とし、上流側の酸化亜鉛膜の原料供給装置及び酸化亜鉛膜のドーピング材料供給装置から供給される原料ガスとドーピングガスの混合ガスを排気ラインに排気できる状態において、上記酸化亜鉛膜の原料供給装置の、容器１２１ｂ及び酸化亜鉛膜の原料１２０ｂの温度を５５～８０℃の範囲の任意の温度、例えば６５℃に設定し、キャリアガス供給源１２３ｂから供給される水素ガスを、キャリアガスの流量計１２４ｂで、３００～８００ｓｃｃｍに、例えば４００ｓｃｃｍ設定する。また、ガス流量調整装置１３１ｂの流量を８００ｓｃｃｍに設定する。
　そうすると、容器１２１ｂの中で、酸化亜鉛原料はキャリアガスの水素ガスによりバブリングされて、気化する。その気化した原料と水素ガスの混合ガスは、上記ガス流量調整装置１３１ｂを介して、流路開閉弁１３３ｂの方へ供給される。
　また、予め、原料ガス温度調整装置１０９により、ガス混合箱１０５及び第１の電極１０１の温度を、８０～１００℃に、例えば９０℃に設定する。
　また、同様に、上記排気ラインに排気できる状態において、上記酸化亜鉛膜のドーピング材料供給装置の、容器１２１ｃ及びドーピング材料１２０ｃの温度を６０～９０℃の範囲の任意の温度、例えば８０℃に設定し、キャリアガス供給源１２３ｃから供給される水素ガスを、キャリアガスの流量計１２４ｃで、２０～８０ｓｃｃｍに、例えば３５ｓｃｃｍ設定する。また、ガス流量調整装置１３１ｃの流量を７０ｓｃｃｍに設定する。
　そうすると、容器１２１ｃの中で、ドーピング材料はキャリアガスの水素ガスによりバブリングされて、気化する。その気化したドーピング材料と水素ガスの混合ガスは、上記ガス流量調整装置１３１ｃを介して、流路開閉弁１３３ｂの方へ供給される。
　そして、上記酸素ガス供給装置の流量計１２９の流量を、３００～８００ｓｃｃｍ、例えば４００ｓｃｃｍに設定する。そうすると、酸素ガスの供給管１３０からガス混合器１０５に流量４００ｓｃｃｍの酸素が供給される。 Further, in FIG. 3, the flow path opening / closing valve 133b is closed in advance, and the mixed gas of the source gas and the doping gas supplied from the upstream zinc oxide film source supply device and the zinc oxide film doping material supply device is exhausted. In a state where the exhaust gas can be exhausted to the line, the temperature of the container 121b and the zinc oxide film material 120b of the zinc oxide film material supply apparatus is set to an arbitrary temperature in the range of 55 to 80 ° C., for example, 65 ° C. The hydrogen gas supplied from the source 123b is set to 300 to 800 sccm, for example, 400 sccm by the carrier gas flow meter 124b. Further, the flow rate of the gas flow rate adjusting device 131b is set to 800 sccm.
Then, in the container 121b, the zinc oxide raw material is bubbled by the carrier gas hydrogen gas and vaporized. The vaporized mixed gas of raw material and hydrogen gas is supplied to the flow path opening / closing valve 133b via the gas flow rate adjusting device 131b.
Further, the temperature of the gas mixing box 105 and the first electrode 101 is previously set to 80 to 100 ° C., for example, 90 ° C. by the source gas temperature adjusting device 109.
Similarly, the temperature of the container 121c and the doping material 120c of the doping material supply device for the zinc oxide film is set to an arbitrary temperature in the range of 60 to 90 ° C., for example, 80 ° C., in a state where the exhaust gas can be exhausted to the exhaust line. Then, the hydrogen gas supplied from the carrier gas supply source 123c is set to 20 to 80 sccm, for example, 35 sccm by the carrier gas flow meter 124c. Further, the flow rate of the gas flow rate adjusting device 131c is set to 70 sccm.
Then, in the container 121c, the doping material is bubbled by the hydrogen gas as the carrier gas and is vaporized. The vaporized mixed gas of doping material and hydrogen gas is supplied to the flow path opening / closing valve 133b via the gas flow rate adjusting device 131c.
Then, the flow rate of the flow meter 129 of the oxygen gas supply device is set to 300 to 800 sccm, for example, 400 sccm. Then, oxygen at a flow rate of 400 sccm is supplied from the oxygen gas supply pipe 130 to the gas mixer 105.
　次に、図３において、発信器１３５から、例えば周波数１３．５６ＭＨｚの正弦波を発生させて、その信号を分配器１３６で２つに分けて、その一方は、位相調整装置１３７を介して第１の電力増幅器１３８ａで電力増幅され、第１のインピーダンス整合器１３９ａ、第１の同軸ケーブル１４０ａ、第１の電流導入端子１４１ａ、第１の芯線１４３ａ等を用いて、第１及び第３の給電点１１０ａ、１１１ａに供給される。他方の信号は、第２の電力増幅器１３８ｂで電力増幅され、第２のインピーダンス整合器１３９ｂ、第２の同軸ケーブル１４０ｂ、第２の電流導入端子１４１ｂ、第２の芯線１４３ｂ等を用いて、第２及び第４の給電点１１０ｂ、１１１ｂに供給される。
　第１及び第２の電力増幅器１３８ａ、１３８ｂの出力は、０．５～２ＫＷの範囲で、例えば１．５ＫＷに設定する。
　供給される２つの電力により発生する、一対の電極間のプラズマの強さは、以下に示す電力の強さの分布に比例したものになる。
　即ち、第１及び第３の給電点１１０ａ、１１１ａ間には次式で表される電力Ｗ１１（ｔ）が、第２及び第４の給電点１１０ｂ、１１１ｂ間には次式で表される電力Ｗ１２（ｔ）が供給される。
　Ｗ１１（ｔ）＝Ａｓｉｎ（ωｔ＋θ１）
　Ｗ１２（ｔ）＝Ａｓｉｎ（ωｔ＋θ２）
ただし、Ａは振幅、ωは角周波数、ｔは時間、θ１、θ２は初期位相である。
　そうすると、一対の電極間の電力の強さは、次式で表されるＩ（ｘ、ｔ）の分布となる。
　　Ｉ（ｘ、ｔ）∝ｃｏｓ２｛２π（ｘ－Ｌ０／２）／λ－Δθ／２｝
ただし、λは電力の波長、Ｌ０は電極の長さ、Δθ＝θ１―θ２である。
　この場合、前記第１のインピーダンス整合器１３９ａ及び第２のインピーダンス整合器１３９ｂを調整することにより、それぞれのインピーダンス整合器１３９ａ、１３９ｂの上流側に上記供給電力の反射波が戻らないようにすることができる。
　また、上記電力の強さの分布は、位相調整装置１３７により位相Δθ＝θ１―θ２を調整することにより、一様に調整できる。
　したがって、一対の電極間のプラズマの強さは、上記Ｉ（ｘ、ｔ）で示される強さの分布になる。 Next, in FIG. 3, a sine wave having a frequency of 13.56 MHz, for example, is generated from the transmitter 135, and the signal is divided into two by a distributor 136, one of which is passed through a phase adjustment device 137. The first and third power feedings are amplified by the first power amplifier 138a and using the first impedance matching unit 139a, the first coaxial cable 140a, the first current introduction terminal 141a, the first core wire 143a, and the like. The points 110a and 111a are supplied. The other signal is amplified by the second power amplifier 138b, and the second impedance matching unit 139b, the second coaxial cable 140b, the second current introduction terminal 141b, the second core wire 143b, and the like are used. 2 and the fourth feeding points 110b and 111b.
The outputs of the first and second power amplifiers 138a and 138b are set in the range of 0.5 to 2 kW, for example, 1.5 kW.
The intensity of the plasma between the pair of electrodes generated by the two supplied electric powers is proportional to the power intensity distribution shown below.
That is, the power W 11 (t) expressed by the following equation is expressed between the first and third feeding points 110a and 111a, and is expressed by the following equation between the second and fourth feeding points 110b and 111b. Electric power W 12 (t) is supplied.
W 11 (t) = Asin (ωt + θ 1 )
W 12 (t) = Asin (ωt + θ 2 )
However, A is an amplitude, ω is an angular frequency, t is time, and θ 1 and θ 2 are initial phases.
Then, the power intensity between the pair of electrodes has a distribution of I (x, t) expressed by the following equation.
I (x, t) ∝cos 2 {2π (x−L0 / 2) / λ−Δθ / 2}
Here, λ is the wavelength of power, L0 is the length of the electrode, and Δθ = θ 1 −θ 2 .
In this case, by adjusting the first impedance matching unit 139a and the second impedance matching unit 139b, the reflected wave of the supplied power is prevented from returning to the upstream side of the respective impedance matching units 139a and 139b. Can do.
The power intensity distribution can be uniformly adjusted by adjusting the phase Δθ = θ 1 −θ 2 by the phase adjusting device 137.
Therefore, the intensity of the plasma between the pair of electrodes has the intensity distribution indicated by I (x, t).
　図３において、上記高周波電力の供給の準備を整えた後、上記流路開閉弁１３３ｂを開にする。そして、酸化亜鉛膜の原料供給装置から供給されるキャリアガスと酸化亜鉛原料ガスの混合ガスを、例えば８００ｓｃｃｍに設定する。
　酸化亜鉛膜のドーピング材料供給装置から供給されるキャリアガスとドーピングガスの流量を、例えば７０ｓｃｃｍにする。また、酸素ガス供給装置から供給される酸素ガスの流量を、例えば４００ｓｃｃｍとする。
　その結果、上記の流量、例えば１２７０ｓｃｃｍが、ガスシャワー１０６から一対の電極１０１、１０３間に流出する。
　そうすると、一対の電極１０１、１０３間には、キャリアガスと、酸化亜鉛原料と、ドーピング材料と、酸素との混合ガスのプラズマが発生する。キャリアガスと、酸化亜鉛原料と、ドーピング材料と、酸素との混合ガスがプラズ化されると、プラズマ化学反応により、酸素ラジカルや亜鉛ラジカルを含む種々のラジカルが発生する。プラズマ中の各種ラジカルは、拡散現象により濃度の高い方から低い方へ拡散する。
　その結果、下地層として酸化チタンが製膜されているガラス基板上に、例えばＧａドープの結晶質酸化亜鉛膜が堆積する。 In FIG. 3, after preparing for the supply of the high-frequency power, the flow path opening / closing valve 133b is opened. Then, the mixed gas of the carrier gas and the zinc oxide source gas supplied from the zinc oxide film source supply device is set to 800 sccm, for example.
The flow rates of the carrier gas and the doping gas supplied from the doping material supply device for the zinc oxide film are set to 70 sccm, for example. Further, the flow rate of the oxygen gas supplied from the oxygen gas supply device is set to 400 sccm, for example.
As a result, the above flow rate, for example 1270 sccm, flows out from the gas shower 106 between the pair of electrodes 101 and 103.
Then, plasma of a mixed gas of a carrier gas, a zinc oxide raw material, a doping material, and oxygen is generated between the pair of electrodes 101 and 103. When a mixed gas of a carrier gas, a zinc oxide raw material, a doping material, and oxygen is plasmized, various radicals including oxygen radicals and zinc radicals are generated by plasma chemical reaction. Various radicals in the plasma diffuse from a higher concentration to a lower concentration due to a diffusion phenomenon.
As a result, for example, a Ga-doped crystalline zinc oxide film is deposited on a glass substrate on which titanium oxide is formed as an underlayer.
　上記の要領で、予備製膜試験（予備製膜工程）として、基板温度、酸化亜鉛膜の原料供給装置のキャリアガスの流量、酸化亜鉛膜のドーピング材料供給装置のキャリアガスの流量、酸素ガスの流量等をパラメータに、製膜時間を例えば１０～３０分間にして、結晶質酸化チタン膜付のガラス基板１０８に酸化亜鉛膜を形成させる。製膜後、真空容器１００から前記基板１０８を取り出して、製膜された酸化亜鉛膜の膜質及び膜厚みを評価する。
　膜質の評価には、レーザラマン分光法、走査型電子顕微鏡（ＳＥＭ）、高分解能透過電子顕微鏡（ＴＥＭ）及び二次イオン質量分析法（ＳＩＭＳ）等を用いる。導電率は導電率測定器を用いる。表面粗さはＪＩＳ　Ｂ０６０１に規定されている測定器を用いる。膜厚は、走査型電子顕微鏡（ＳＥＭ）、段差計、あるいは分光エリプソメータで測定する。 In the above manner, as a preliminary film formation test (preliminary film formation step), the substrate temperature, the flow rate of the carrier gas of the raw material supply device of the zinc oxide film, the flow rate of the carrier gas of the doping material supply device of the zinc oxide film, The zinc oxide film is formed on the glass substrate 108 with the crystalline titanium oxide film by using the flow rate as a parameter and the film forming time, for example, for 10 to 30 minutes. After film formation, the substrate 108 is taken out from the vacuum vessel 100, and the film quality and film thickness of the formed zinc oxide film are evaluated.
For the evaluation of the film quality, laser Raman spectroscopy, scanning electron microscope (SEM), high resolution transmission electron microscope (TEM), secondary ion mass spectrometry (SIMS), or the like is used. Conductivity is measured using a conductivity meter. For the surface roughness, a measuring instrument defined in JIS B0601 is used. The film thickness is measured with a scanning electron microscope (SEM), a step meter, or a spectroscopic ellipsometer.
　上記予備製膜試験（予備製膜工程）において、基板１０８は膜厚２０ｎｍ以上の酸化チタン膜が製膜されているガラス板であり、該基板１０８の温度が２００～４００℃の範囲に設定されれば、該基板１０８に製膜される膜は、すべて、結晶質の酸化亜鉛になるという結果が得られる。即ち、製膜速度は、高周波電力、原料の流量、キャリアガスの流量、及び圧力に依存するが、製膜される酸化亜鉛膜の膜質は、図８に示しているように、結晶質になる。
　なお、図８は、横軸に製膜時間を、縦軸に膜厚と膜質をとることにより、製膜条件として下地が結晶質酸化チタン膜で、基板温度が２００～４００℃の場合に得られる酸化亜鉛膜の特性を示している。
　また、製膜される酸化亜鉛膜の表面の凹凸は、ＪＩＳ　Ｂ０６０１で定義される算術平均粗さで、２０～１４０ｎｍ程度になる。
　結晶質酸化亜鉛の製膜速度は、上記試験条件の場合、即ち、キャリアガスと酸化亜鉛原料の混合ガスの流量８００ｓｃｃｍ、酸素ガスの流量４００ｓｃｃｍ、キャリアガスとドーピングガスの混合ガスの流量７０ｓｃｃｍ、圧力０．０５Ｔｏｒｒ（６．６５Ｐａ）及び高周波電力１．５ＫＷの場合は、５０ｎｍ／分程度が得られる。
　なお、製膜速度は、高周波電力及び原料ガスを増大することにより、改善することが可能である。
　結晶質酸化亜鉛の比抵抗は、上記試験条件の場合、５～１４ｘ１０－４Ω・ｃｍが得られる。なお、該酸化亜鉛膜の導電率はド－ピング材料の供給の仕方に依存するので、条件を最適化することが必要である。 In the preliminary film formation test (preliminary film formation step), the substrate 108 is a glass plate on which a titanium oxide film having a thickness of 20 nm or more is formed, and the temperature of the substrate 108 is set in a range of 200 to 400 ° C. As a result, all the films formed on the substrate 108 become crystalline zinc oxide. That is, the film forming speed depends on the high-frequency power, the flow rate of the raw material, the flow rate of the carrier gas, and the pressure, but the film quality of the zinc oxide film to be formed becomes crystalline as shown in FIG. .
In FIG. 8, the horizontal axis indicates the film forming time, and the vertical axis indicates the film thickness and film quality. As a film forming condition, the base is a crystalline titanium oxide film and the substrate temperature is 200 to 400 ° C. The characteristic of the zinc oxide film | membrane obtained is shown.
Further, the unevenness of the surface of the zinc oxide film to be formed is about 20 to 140 nm in terms of arithmetic average roughness defined by JIS B0601.
The film formation rate of the crystalline zinc oxide is the same as in the above test conditions, that is, the flow rate of the mixed gas of the carrier gas and the zinc oxide raw material is 800 sccm, the flow rate of the oxygen gas is 400 sccm, the flow rate of the mixed gas of the carrier gas and the doping gas is 70 sccm, and the pressure In the case of 0.05 Torr (6.65 Pa) and high frequency power of 1.5 kW, about 50 nm / min is obtained.
In addition, the film forming speed can be improved by increasing the high-frequency power and the raw material gas.
The specific resistance of crystalline zinc oxide is 5 to 14 × 10 −4 Ω · cm under the above test conditions. Note that the conductivity of the zinc oxide film depends on how the doping material is supplied, so it is necessary to optimize the conditions.
　次に、本発明の第１の実施形態に係わる薄膜太陽電池用基板１ａの製膜試験（製造工程）について説明する。この製膜試験では、上記予備製膜試験（予備製膜工程）の結果をベースに、図１に示される本発明の第１の実施形態に係わる薄膜太陽電池用基板１ａを製造する。その手順について、以下に説明する。
　図１図示の薄膜太陽電池用基板１ａは、ガラス基板２の上に、非晶質酸化チタン層４ａと結晶質酸化チタン層４ｂが積層され、該結晶質酸化チタン層４ｂの上に結晶質酸化亜鉛層５が積層されるという構造を有する。
　ここでは、上記非晶質酸化チタン層４ａに、基板ガラス２からのアルカリ分や水分の拡散防止層としての効果を持たせるために、その膜厚を１０～５０ｎｍの範囲に、例えば２０ｎｍに設定する。
　また、上記結晶質酸化チタン層４ｂは、この膜の上に積層される結晶質酸化亜鉛５の結晶成長を促進させる効果を持たせるための下地層として、その膜厚を２０～２００ｎｍの範囲に、例えば１００ｎｍに設定する。
　また、上記結晶質酸化亜鉛層５は、薄膜太陽電池用基板として必要な特性、即ち、凹凸構造を有し、高導電性で、高光透過性を有することという特性を持たせるために、その膜厚を２００～２０００ｎｍの範囲に、例えば８００ｎｍに設定する。なお、２００ｎｍ程度より薄いと、製膜される酸化亜鉛の結晶粒の大きさが充分でなく、その結果、凹凸構造の一つの目安である表面粗さが算術平均粗さ１５～１５０ｎｍの範囲にならないことがある。また、膜厚が２０００ｎｍ程度を超えると、製膜時間が長くなりコスト高になることに加えて、光透過性が低下するという問題が起こることがある。 Next, a film forming test (manufacturing process) of the thin film solar cell substrate 1a according to the first embodiment of the present invention will be described. In this film forming test, a thin film solar cell substrate 1a according to the first embodiment of the present invention shown in FIG. 1 is manufactured based on the result of the preliminary film forming test (preliminary film forming step). The procedure will be described below.
In the thin film solar cell substrate 1a shown in FIG. 1, an amorphous titanium oxide layer 4a and a crystalline titanium oxide layer 4b are stacked on a glass substrate 2, and a crystalline oxide layer is formed on the crystalline titanium oxide layer 4b. It has a structure in which the zinc layer 5 is laminated.
Here, in order to give the amorphous titanium oxide layer 4a the effect of preventing diffusion of alkali and moisture from the substrate glass 2, the film thickness is set in the range of 10 to 50 nm, for example, 20 nm. To do.
The crystalline titanium oxide layer 4b has a thickness in the range of 20 to 200 nm as an underlayer for providing an effect of promoting crystal growth of the crystalline zinc oxide 5 laminated on the film. For example, it is set to 100 nm.
Further, the crystalline zinc oxide layer 5 has a characteristic necessary as a substrate for a thin film solar cell, that is, a film having an uneven structure, a high conductivity and a high light transmittance. The thickness is set in the range of 200 to 2000 nm, for example, 800 nm. If the thickness is less than about 200 nm, the crystal grain size of the zinc oxide film to be formed is not sufficient. It may not be. On the other hand, when the film thickness exceeds about 2000 nm, the film forming time becomes longer and the cost is increased, and there is a problem that the light transmittance is lowered.
　上記膜厚２０ｎｍの非晶質酸化チタン層４ａは、図２に示される本発明の第１の実施形態に係わる酸化チタン（ＴｉＯ２）膜を製造するための高周波プラズマＣＶＤ装置を用いて製膜する。製膜条件は、図４及び図６に示される上記予備製膜の結果を参考にする。
　図２において、基板１０８として、サイズ１．５ｍｘ０．２５ｍｘ厚み４ｍｍのガラスを基板リフター１１２及び図示しない基板搬入出ゲート１１８を用いて、第２の電極１０３上に設置する。この場合、一対の電極１０１、１０３の間隔を２５ｍｍに設定する。
　そして、図示しない基板ヒータ１０２により、基板１０８の温度を、５０～４５０℃の範囲に、例えば２００℃に設定する。
　そして、図示しない真空ポンプを稼動させ、真空容器１内の不純物ガス等を除去する。
　そして、真空容器１００内の圧力を、上記圧力調整装置により、０．０１Ｔｏｒｒ～１Ｔｏｒｒ（１．３３Ｐａ～１３３Ｐａ）の範囲、例えば０．０５Ｔｏｒｒ（６．６５Ｐａ）に設定する。 The amorphous titanium oxide layer 4a having a thickness of 20 nm is formed using a high-frequency plasma CVD apparatus for manufacturing a titanium oxide (TiO 2) film according to the first embodiment of the present invention shown in FIG. . Regarding the film forming conditions, the results of the preliminary film forming shown in FIGS. 4 and 6 are referred to.
In FIG. 2, as a substrate 108, glass having a size of 1.5 mx 0.25 mx 4 mm in thickness is placed on the second electrode 103 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown). In this case, the interval between the pair of electrodes 101 and 103 is set to 25 mm.
Then, the substrate heater 102 (not shown) sets the temperature of the substrate 108 in a range of 50 to 450 ° C., for example, 200 ° C.
And the vacuum pump which is not illustrated is operated and the impurity gas etc. in the vacuum vessel 1 are removed.
Then, the pressure in the vacuum vessel 100 is set to a range of 0.01 Torr to 1 Torr (1.33 Pa to 133 Pa), for example, 0.05 Torr (6.65 Pa) by the pressure adjusting device.
　先ず、上記予備製膜試験（予備製膜工程）において非晶質酸化チタン層を製膜する場合と同様の要領により、非晶質酸化チタン層４ａを製膜する。この場合、キャリアガスとＴＴＩＰ原料の混合ガスの流量を８００ｓｃｃｍ、酸素ガスの流量を４００ｓｃｃｍに設定し、高周波電力は１．５ＫＷとする。製膜時間は、２分間とする。この場合は、製膜される非晶質酸化チタン層は、概ね図４の特性に従うことになる。
　その結果、上記予備製膜試験（予備製膜工程）での製膜速度は１０ｎｍ／分であるので、ガラス基板１０８に膜厚２０ｎｍの非晶質酸化チタン層４ａが製膜される。
　次に、上記予備製膜試験（予備製膜工程）において結晶質酸化チタン層を製膜する場合と同様の要領により、結晶質酸化チタン層４ａを製膜する。この場合、基板温度を３９０℃に、キャリアガスとＴＴＩＰ原料の混合ガスの流量を８００ｓｃｃｍ、酸素ガスの流量を４００ｓｃｃｍに設定し、高周波電力は１．５ＫＷとする。製膜時間は、５分間とする。この場合は、製膜される非晶質酸化チタン層は、概ね図６の特性に従うことになる。
　その結果、上記予備製膜試験（予備製膜工程）での結晶質酸化チタン層の製膜速度は２０ｎｍ／分であるので、ガラス基板１０８に製膜された非晶質酸化チタン層４ａの上に、膜厚１００ｎｍの結晶質酸化チタン層４ｂが製膜される。
　次に、上記予備製膜試験（予備製膜工程）において結晶質酸化亜鉛層を製膜する場合と同様の要領により、結晶質酸化亜鉛層５を製膜する。この場合、基板温度を３５０℃に、キャリアガスと原料の混合ガスの流量を８００ｓｃｃｍ、酸素ガスの流量を４００ｓｃｃｍ、キャリアガスとドーピング材料ガスの混合ガスの流量を７０ｓｃｃｍに設定し、高周波電力は１．５ＫＷとする。製膜時間は、１６分間とする。この場合は、製膜される結晶質酸化亜鉛層は、概ね図８の特性に従うことになる。
　その結果、上記予備製膜試験（予備製膜工程）での結晶質酸化亜鉛層の製膜速度は５０ｎｍ／分であるので、ガラス基板１０８に積層された非晶質酸化チタン層４ａと結晶質酸化チタン層４ｂの上に、膜厚８００ｎｍのＧａドープ結晶質酸化亜鉛層５が製膜される。
　次に、上記真空容器１００内の圧力を大気圧に戻し、図示しない基板搬入出ゲート１１８を用いて、非晶質酸化チタン層４ａと、結晶質酸化チタン層４ｂと、Ｇａドープ結晶質酸化亜鉛層５が積層されたガラス基板１０８を取り出す。その結果、所要の薄膜太陽電池用基板１ａが得られる。 First, the amorphous titanium oxide layer 4a is formed in the same manner as in the case of forming the amorphous titanium oxide layer in the preliminary film forming test (preliminary film forming step). In this case, the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm, the flow rate of the oxygen gas is set to 400 sccm, and the high-frequency power is 1.5 kW. The film formation time is 2 minutes. In this case, the amorphous titanium oxide layer to be formed generally follows the characteristics shown in FIG.
As a result, since the film forming speed in the preliminary film forming test (preliminary film forming step) is 10 nm / min, an amorphous titanium oxide layer 4 a having a film thickness of 20 nm is formed on the glass substrate 108.
Next, the crystalline titanium oxide layer 4a is formed in the same manner as in the case of forming the crystalline titanium oxide layer in the preliminary film forming test (preliminary film forming step). In this case, the substrate temperature is set to 390 ° C., the flow rate of the mixed gas of the carrier gas and the TTIP material is set to 800 sccm, the flow rate of the oxygen gas is set to 400 sccm, and the high frequency power is 1.5 kW. The film forming time is 5 minutes. In this case, the amorphous titanium oxide layer to be formed generally follows the characteristics shown in FIG.
As a result, the film-forming speed of the crystalline titanium oxide layer in the preliminary film-forming test (preliminary film-forming step) is 20 nm / min, so that the upper surface of the amorphous titanium oxide layer 4a formed on the glass substrate 108 is Then, a crystalline titanium oxide layer 4b having a thickness of 100 nm is formed.
Next, the crystalline zinc oxide layer 5 is formed in the same manner as in the case of forming the crystalline zinc oxide layer in the preliminary film forming test (preliminary film forming step). In this case, the substrate temperature is set to 350 ° C., the flow rate of the mixed gas of the carrier gas and the raw material is set to 800 sccm, the flow rate of the oxygen gas is set to 400 sccm, the flow rate of the mixed gas of the carrier gas and the doping material gas is set to 70 sccm. .5KW. The film formation time is 16 minutes. In this case, the formed crystalline zinc oxide layer generally follows the characteristics shown in FIG.
As a result, the film forming speed of the crystalline zinc oxide layer in the preliminary film forming test (preliminary film forming step) is 50 nm / min. Therefore, the amorphous titanium oxide layer 4a laminated on the glass substrate 108 and the crystalline A 800 nm-thick Ga-doped crystalline zinc oxide layer 5 is formed on the titanium oxide layer 4b.
Next, the pressure in the vacuum vessel 100 is returned to atmospheric pressure, and an amorphous titanium oxide layer 4a, a crystalline titanium oxide layer 4b, and a Ga-doped crystalline zinc oxide are used using a substrate carry-in / out gate 118 (not shown). The glass substrate 108 on which the layer 5 is laminated is taken out. As a result, a required thin film solar cell substrate 1a is obtained.
　本実施例では、第１の電極１０１のサイズが長さ１．５ｍｘ幅０．３ｍｘ厚み２０ｍｍであるので、基板サイズは、上記１．５ｍｘ０．２５ｍｘ厚み４ｍｍのガラス基板に、に制約されるが、第１及び第２の電極１０１、１０３からなる一対の電極の個数を増加すれば基板サイズの幅は拡大可能であることは当然のことである。 In the present embodiment, since the size of the first electrode 101 is 1.5 mx width 0.3 mx 20 mm in thickness, the substrate size is limited to the glass substrate of 1.5 mx 0.25 mx 4 mm in thickness. Of course, the width of the substrate size can be increased by increasing the number of the pair of electrodes including the first and second electrodes 101 and 103.
　得られた薄膜太陽電池用基板１ａは、アモルファスシリコン太陽電池や、タンデム型薄膜太陽電池（光入射側から順に、アモルファスシリコン発電層と微結晶シリコン発電層が積層される薄膜太陽電池）の基板に応用される。その応用について、以下に説明する。
　なお、アモルファスシリコン太陽電池やタンデム型薄膜太陽電池の製造方法は、公知である。
　アモルファスシリコン太陽電池製造への応用では、図１１に示すように、上記薄膜太陽電池用基板１ａ、即ち、ガラス基板２の上に順に積層された非晶質酸化チタン層４ａと、結晶質酸化チタン層４ｂと、Ｇａドープ結晶質酸化亜鉛層５からなる基板に、プラズマＣＶＤ法により、製膜温度１７０～２５０℃において、膜厚７～１５ｎｍ、例えば１０ｎｍの非晶質ｐ層６と、膜厚１５０～４００ｎｍ、例えば３００ｎｍの非晶質ｉ層７と、膜厚５～３０ｎｍ、例えば２０ｎｍの非晶質ｎ層８とを積層する。その後、スパッタ法により、製膜温度２００～３００℃において、膜厚１０～１００ｎｍ、例えば１５ｎｍのＧａドープのＺｎＯ層９と、膜厚１００～３００ｎｍ、例えば２００ｎｍのＡｇ裏面電極１０とを積層する。
　その結果、安定化発電効率が８．５～９．５％という性能の良いアモルファスシリコン太陽電池セルが得られる。 The obtained thin film solar cell substrate 1a is an amorphous silicon solar cell or a tandem thin film solar cell (a thin film solar cell in which an amorphous silicon power generation layer and a microcrystalline silicon power generation layer are stacked in order from the light incident side). Applied. The application will be described below.
In addition, the manufacturing method of an amorphous silicon solar cell or a tandem-type thin film solar cell is publicly known.
In application to amorphous silicon solar cell production, as shown in FIG. 11, the thin film solar cell substrate 1 a, that is, the amorphous titanium oxide layer 4 a sequentially laminated on the glass substrate 2, and crystalline titanium oxide An amorphous p layer 6 having a film thickness of 7 to 15 nm, for example, 10 nm, and a film thickness are formed on a substrate composed of the layer 4b and the Ga-doped crystalline zinc oxide layer 5 by a plasma CVD method at a film forming temperature of 170 to 250 ° C. An amorphous i layer 7 having a thickness of 150 to 400 nm, for example, 300 nm, and an amorphous n layer 8 having a thickness of 5 to 30 nm, for example, 20 nm are stacked. Thereafter, a Ga-doped ZnO layer 9 having a film thickness of 10 to 100 nm, for example, 15 nm, and an Ag back electrode 10 having a film thickness of 100 to 300 nm, for example, 200 nm are laminated at a film formation temperature of 200 to 300 ° C. by sputtering.
As a result, it is possible to obtain an amorphous silicon solar cell having a high performance with a stabilized power generation efficiency of 8.5 to 9.5%.
　タンデム型薄膜太陽電池製造への応用では、図１２に示すように、上記薄膜太陽電池用基板１ａ、即ち、ガラス基板２の上に順に積層された非晶質酸化チタン層４ａと、結晶質酸化チタン層４ｂと、Ｇａドープ結晶質酸化亜鉛層５からなる基板に、プラズマＣＶＤ法により、製膜温度１７０～２５０℃において、膜厚７～１５ｎｍ、例えば１０ｎｍの非晶質ｐ層６と、膜厚１５０～４００ｎｍ、例えば３００ｎｍの非晶質ｉ層７と、膜厚５～３０ｎｍ、例えば２０ｎｍの非晶質ｎ層８とを積層する。そして、スパッタ法により、製膜温度２００～３００℃において、膜厚５０～１００ｎｍ、例えば８０ｎｍのＧａドープのＺｎＯの中間層１１を製膜する。
　その後、プラズマＣＶＤ法により、製膜温度１７０～２５０℃において、膜厚１０～３０ｎｍ、例えば２０ｎｍの微結晶ｐ層１２と、膜厚１．５～４μｍ、例えば２．５μｍの微結晶ｉ層１３と、膜厚５～３０ｎｍ、例えば２０ｎｍの微結
晶ｎ層１４とを積層する。
　そして、スパッタ法により、製膜温度２００～３００℃において、膜厚２０～１００ｎｍ、例えば４０ｎｍのＧａドープのＺｎＯ層９と、膜厚１００～３００ｎｍ、例えば２００ｎｍのＡｇ裏面電極１０とを積層する。
　その結果、安定化発電効率が１３～１４．５％という性能の良いタンデム型薄膜太陽電池セルが得られる。 In application to the production of a tandem-type thin film solar cell, as shown in FIG. 12, the amorphous titanium oxide layer 4a sequentially laminated on the thin film solar cell substrate 1a, that is, the glass substrate 2, and the crystalline oxidation An amorphous p layer 6 having a film thickness of 7 to 15 nm, for example, 10 nm, and a film are formed on a substrate composed of the titanium layer 4b and the Ga-doped crystalline zinc oxide layer 5 by a plasma CVD method at a film forming temperature of 170 to 250 ° C. An amorphous i layer 7 having a thickness of 150 to 400 nm, for example, 300 nm, and an amorphous n layer 8 having a thickness of 5 to 30 nm, for example, 20 nm are stacked. Then, a Ga-doped ZnO intermediate layer 11 having a film thickness of 50 to 100 nm, for example, 80 nm, is formed at a film forming temperature of 200 to 300 ° C. by sputtering.
Thereafter, by a plasma CVD method, at a film forming temperature of 170 to 250 ° C., a microcrystalline p layer 12 having a thickness of 10 to 30 nm, for example, 20 nm, and a microcrystalline i layer 13 having a thickness of 1.5 to 4 μm, for example, 2.5 μm. Then, a microcrystalline n layer 14 having a thickness of 5 to 30 nm, for example, 20 nm is stacked.
Then, a Ga-doped ZnO layer 9 having a film thickness of 20 to 100 nm, for example, 40 nm, and an Ag back electrode 10 having a film thickness of 100 to 300 nm, for example, 200 nm are stacked at a film forming temperature of 200 to 300 ° C. by sputtering.
As a result, it is possible to obtain a tandem-type thin film solar cell having a good performance with a stabilized power generation efficiency of 13 to 14.5%.
　次に、本発明の第２の実施形態に係わる薄膜太陽電池用基板及びその製造方法について、図１１を参照して説明する。また、図２～図５及び図８を参照する。 Next, a thin film solar cell substrate and a method for manufacturing the same according to a second embodiment of the present invention will be described with reference to FIG. Reference is also made to FIGS. 2 to 5 and FIG.
　図１１は、本発明の第２の実施形態に係わる薄膜太陽電池用基板の断面を概略的に示す構造図である。
　図１１において、符号２は、透光性絶縁基板で、例えば厚みが４～５ｍｍのガラス基板である。
　符号３ｂは酸化チタン層で、非晶質酸化チタン層４ａと、非晶質酸化チタン及び結晶質酸化チタンが混在した状態にある酸化チタン膜（ここでは、非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン膜と呼ぶ）層４ｃと、結晶質酸化チタン層４ｂの３層から構成される。
　非晶質酸化チタン層４ａ、結晶質酸化チタン層４ｂ、非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン４ｃは、いずれも、前述の、図２に示される高周波プラズマＣＶＤ装置により製膜される。
　符号５は結晶質酸化亜鉛（ＺｎＯ）膜層である。この結晶質酸化亜鉛（ＺｎＯ）膜層は、前述の、図３に示される高周波プラズマＣＶＤ装置により製膜される。また、この結晶質酸化亜鉛（ＺｎＯ）膜層５の製膜は、スパッタ装置を用いてもよい。 FIG. 11 is a structural diagram schematically showing a cross section of a thin-film solar cell substrate according to the second embodiment of the present invention.
In FIG. 11, reference numeral 2 denotes a translucent insulating substrate, for example, a glass substrate having a thickness of 4 to 5 mm.
Reference numeral 3b denotes a titanium oxide layer, which is an amorphous titanium oxide layer 4a and a titanium oxide film in which amorphous titanium oxide and crystalline titanium oxide are mixed (here, amorphous titanium oxide and crystalline titanium oxide). (Referred to as a mixed phase titanium oxide film) and a crystalline titanium oxide layer 4b.
Amorphous titanium oxide layer 4a, crystalline titanium oxide layer 4b, amorphous titanium oxide, and mixed phase titanium oxide 4c of crystalline titanium oxide are all formed by the above-described high-frequency plasma CVD apparatus shown in FIG. Is done.
Reference numeral 5 denotes a crystalline zinc oxide (ZnO) film layer. This crystalline zinc oxide (ZnO) film layer is formed by the above-described high-frequency plasma CVD apparatus shown in FIG. In addition, the crystalline zinc oxide (ZnO) film layer 5 may be formed by using a sputtering apparatus.
　次に、本発明の第２の実施形態に係わる薄膜太陽電池用基板の製膜試験（製造工程）について説明する。この製膜試験では、上記予備製膜試験（予備製膜工程）の結果をベースに、図１１に示される本発明の第２の実施形態に係わる薄膜太陽電池用基板を製造する。その手順について、以下に説明する。
　図１１図示の薄膜太陽電池用基板１ｂは、ガラス基板２の上に、非晶質酸化チタン層４ａと、非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン４ｃと、結晶質酸化チタン層４ｂが積層され、該結晶質酸化チタン層４ｂの上に結晶質酸化亜鉛層５が積層されるという構造を有する。
　ここでは、上記非晶質酸化チタン層４ａに、基板ガラス２からのアルカリ分や水分の拡散防止層としての効果を持たせるために、その膜厚を１０～５０ｎｍの範囲に、例えば４０ｎｍに設定する。
　また、非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン４ｃの膜厚は、特に制御せずに自然に形成されるものを活用する。
　また、上記結晶質酸化チタン層４ｂは、この膜の上に積層される結晶質酸化亜鉛５の結晶成長を促進させる効果を持たせるための下地層として、その膜厚を２０～２００ｎｍの範囲に、例えば１００ｎｍに設定する。
　また、上記結晶質酸化亜鉛層５は、薄膜太陽電池用基板として必要な特性、即ち、凹凸構造を有し、高導電性で、高光透過性を有することという特性を持たせるために、その膜厚を２００～２０００ｎｍの範囲に、例えば８００ｎｍに設定する。なお、２００ｎｍ程度より薄いと、製膜される結晶粒の大きさが充分でなく、その結果、凹凸構造の一つの目安である表面粗さが算術平均粗さ１５～１５０ｎｍの範囲にならないことがある。また、膜厚が２０００ｎｍ程度を超えると、製膜時間が長くなりコスト高になることに加えて、光透過性が低下するという問題が起こることがある。 Next, a film forming test (manufacturing process) of the thin film solar cell substrate according to the second embodiment of the present invention will be described. In this film forming test, a thin film solar cell substrate according to the second embodiment of the present invention shown in FIG. 11 is manufactured based on the result of the preliminary film forming test (preliminary film forming step). The procedure will be described below.
A thin film solar cell substrate 1b shown in FIG. 11 includes an amorphous titanium oxide layer 4a, a mixed phase titanium oxide 4c of amorphous titanium oxide and crystalline titanium oxide, and a crystalline titanium oxide layer on a glass substrate 2. 4b is laminated, and the crystalline zinc oxide layer 5 is laminated on the crystalline titanium oxide layer 4b.
Here, in order to give the amorphous titanium oxide layer 4a an effect as an anti-diffusion layer for alkali and moisture from the substrate glass 2, the film thickness is set in the range of 10 to 50 nm, for example, 40 nm. To do.
Further, the film thickness of the mixed phase titanium oxide 4c of amorphous titanium oxide and crystalline titanium oxide is utilized without being particularly controlled.
The crystalline titanium oxide layer 4b has a thickness in the range of 20 to 200 nm as an underlayer for providing an effect of promoting crystal growth of the crystalline zinc oxide 5 laminated on the film. For example, it is set to 100 nm.
Further, the crystalline zinc oxide layer 5 has a characteristic necessary as a substrate for a thin film solar cell, that is, a film having an uneven structure, a high conductivity and a high light transmittance. The thickness is set in the range of 200 to 2000 nm, for example, 800 nm. If the thickness is less than about 200 nm, the size of the crystal grains to be formed is not sufficient, and as a result, the surface roughness, which is one measure of the concavo-convex structure, does not fall within the arithmetic average roughness of 15 to 150 nm. is there. On the other hand, when the film thickness exceeds about 2000 nm, the film forming time becomes longer and the cost is increased, and there is a problem that the light transmittance is lowered.
　上記膜厚４０ｎｍの非晶質酸化チタン層４ａは、図２に示される酸化チタン（ＴｉＯ２）膜を製造するための高周波プラズマＣＶＤ装置を用いて製膜する。製膜条件は、図４及び図５に示される上記予備製膜の結果を参考にする。
　図２において、基板１０８として、サイズ１．５ｍｘ０．２５ｍｘ厚み４ｍｍのガラスを基板リフター１１２及び図示しない基板搬入出ゲート１１８を用いて、第２の電極１０３上に設置する。この場合、一対の電極１０１、１０３の間隔を２５ｍｍに設定する。
　そして、図示しない基板ヒータ１０２により、基板１０８の温度を、５０～４５０℃の範囲に、例えば２００℃に設定する。
　そして、図示しない真空ポンプを稼動させ、真空容器１内の不純物ガス等を除去する。
　そして、真空容器１００内の圧力を、上記圧力調整装置により、０．０１Ｔｏｒｒ～１Ｔｏｒｒ（１．３３Ｐａ～１３３Ｐａ）の範囲、例えば０．０５Ｔｏｒｒ（６．６５Ｐａ）に設定する。 The amorphous titanium oxide layer 4a having a thickness of 40 nm is formed using a high frequency plasma CVD apparatus for manufacturing a titanium oxide (TiO2) film shown in FIG. Regarding the film forming conditions, the results of the preliminary film forming shown in FIGS. 4 and 5 are referred to.
In FIG. 2, as a substrate 108, glass having a size of 1.5 mx 0.25 mx 4 mm in thickness is placed on the second electrode 103 using a substrate lifter 112 and a substrate carry-in / out gate 118 (not shown). In this case, the interval between the pair of electrodes 101 and 103 is set to 25 mm.
Then, the substrate heater 102 (not shown) sets the temperature of the substrate 108 in a range of 50 to 450 ° C., for example, 200 ° C.
And the vacuum pump which is not illustrated is operated and the impurity gas etc. in the vacuum vessel 1 are removed.
Then, the pressure in the vacuum vessel 100 is set to a range of 0.01 Torr to 1 Torr (1.33 Pa to 133 Pa), for example, 0.05 Torr (6.65 Pa) by the pressure adjusting device.
　先ず、上記予備製膜試験（予備製膜工程）での非晶質酸化チタン層の製膜の場合と同様の要領により、非晶質酸化チタン層４ａを製膜する。この場合、キャリアガスとＴＴＩＰ原料の混合ガスの流量を８００ｓｃｃｍ、酸素ガスの流量を４００ｓｃｃｍに設定し、高周波電力は１．５ＫＷとする。製膜時間は、４分間とする。この場合は、製膜される非晶質酸化チタン層は、概ね図４の特性に従うことになる。
　その結果、上記予備製膜試験（予備製膜工程）での製膜速度は１０ｎｍ／分であるので、ガラス基板１０８に膜厚４０ｎｍの非晶質酸化チタン層４ａが製膜される。
　次に、上記予備製膜試験（予備製膜工程）での結晶質酸化チタン層の製膜の場合と同様の要領により、結晶質酸化チタン層４ａを製膜する。この場合、基板温度を３５０℃に、キャリアガスとＴＴＩＰ原料の混合ガスの流量を８００ｓｃｃｍ、酸素ガスの流量を４００ｓｃｃｍに設定し、高周波電力は１．５ＫＷとする。製膜時間は、１０分間とする。この場合は、製膜される非晶質酸化チタン４ａ及び結晶質酸化チタンの混相酸化チタン４ｃと、結晶質酸化チタン層４ｂは、概ね図５の特性に従うことになる。
　その結果、上記予備製膜試験（予備製膜工程）での結晶質酸化チタン層４ｂの製膜速度は１０ｎｍ／分であるので、ガラス基板１０８に製膜された非晶質酸化チタン層４ａの上に、膜厚１００ｎｍの結晶質酸化チタン層３ａが製膜される。ただし、上記膜厚４０ｎｍの非晶質酸化チタン膜層４ａと該膜厚１００ｎｍの結晶質酸化チタン層４ｂの間には、自然に形成される非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン４ｃがある、その膜厚は概略、２０ｎｍ程度である。
　次に、上記予備製膜試験（予備製膜工程）での結晶質酸化亜鉛層の製膜の場合と同様の要領により、結晶質酸化亜鉛層５を製膜する。この場合、基板温度を３５０℃に、キャリアガスと原料の混合ガスの流量を８００ｓｃｃｍ、酸素ガスの流量を４００ｓｃｃｍ、キャリアガスとドーピング材料ガスの混合ガスの流量を７０ｓｃｃｍに設定し、高周波電力は１．５ＫＷとする。製膜時間は、１６分間とする。この場合は、製膜される非晶質酸化チタン層は、概ね図８の特性に従うことになる。
　その結果、上記予備製膜試験（予備製膜工程）での結晶質酸化亜鉛層の製膜速度は５０ｎｍ／分であるので、ガラス基板１０８に積層された非晶質酸化チタン層４ａと、非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン４ｃと、結晶質酸化チタン層４ｂの上に、膜厚８００ｎｍのＧａドープ結晶質酸化亜鉛層５が製膜される。
　次に、上記真空容器１００内の圧力を大気圧に戻し、図示しない基板搬入出ゲート１１８を用いて、非晶質酸化チタン層４ａと、非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン４ｃと、結晶質酸化チタン層４ｂと、Ｇａドープ結晶質酸化亜鉛層５が積層されたガラス基板１０８を取り出す。その結果、所要の薄膜太陽電池用基板１ｂが得られる。 First, the amorphous titanium oxide layer 4a is formed in the same manner as in the case of forming the amorphous titanium oxide layer in the preliminary film forming test (preliminary film forming step). In this case, the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm, the flow rate of the oxygen gas is set to 400 sccm, and the high-frequency power is 1.5 kW. The film formation time is 4 minutes. In this case, the amorphous titanium oxide layer to be formed generally follows the characteristics shown in FIG.
As a result, since the film forming speed in the preliminary film forming test (preliminary film forming step) is 10 nm / min, an amorphous titanium oxide layer 4 a having a film thickness of 40 nm is formed on the glass substrate 108.
Next, the crystalline titanium oxide layer 4a is formed in the same manner as in the case of forming the crystalline titanium oxide layer in the preliminary film forming test (preliminary film forming step). In this case, the substrate temperature is set to 350 ° C., the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm, the flow rate of the oxygen gas is set to 400 sccm, and the high frequency power is 1.5 kW. The film formation time is 10 minutes. In this case, the amorphous titanium oxide 4a and crystalline titanium oxide mixed phase titanium oxide 4c to be formed and the crystalline titanium oxide layer 4b generally follow the characteristics shown in FIG.
As a result, the film-forming speed of the crystalline titanium oxide layer 4b in the preliminary film-forming test (preliminary film-forming step) is 10 nm / min, so that the amorphous titanium oxide layer 4a formed on the glass substrate 108 is formed. A crystalline titanium oxide layer 3a having a thickness of 100 nm is formed thereon. However, between the amorphous titanium oxide film layer 4a having a thickness of 40 nm and the crystalline titanium oxide layer 4b having a thickness of 100 nm, a mixed phase oxidation of amorphous titanium oxide and crystalline titanium oxide formed naturally is performed. There is titanium 4c, and its film thickness is about 20 nm.
Next, the crystalline zinc oxide layer 5 is formed in the same manner as in the case of forming the crystalline zinc oxide layer in the preliminary film forming test (preliminary film forming step). In this case, the substrate temperature is set to 350 ° C., the flow rate of the mixed gas of the carrier gas and the raw material is set to 800 sccm, the flow rate of the oxygen gas is set to 400 sccm, the flow rate of the mixed gas of the carrier gas and the doping material gas is set to 70 sccm. .5KW. The film formation time is 16 minutes. In this case, the amorphous titanium oxide layer to be formed generally follows the characteristics shown in FIG.
As a result, the film-forming speed of the crystalline zinc oxide layer in the preliminary film-forming test (preliminary film-forming process) is 50 nm / min. Therefore, the amorphous titanium oxide layer 4a laminated on the glass substrate 108 and A 800 nm-thick Ga-doped crystalline zinc oxide layer 5 is formed on the crystalline titanium oxide and the mixed phase titanium oxide 4c of crystalline titanium oxide and the crystalline titanium oxide layer 4b.
Next, the pressure in the vacuum vessel 100 is returned to atmospheric pressure, and an amorphous titanium oxide layer 4a and a mixed phase titanium oxide of amorphous titanium oxide and crystalline titanium oxide are used by using a substrate carry-in / out gate 118 (not shown). The glass substrate 108 on which 4c, the crystalline titanium oxide layer 4b and the Ga-doped crystalline zinc oxide layer 5 are laminated is taken out. As a result, the required thin film solar cell substrate 1b is obtained.
　上記図１１に示される本発明の第２の実施形態に係わる薄膜太陽電池用基板の製造方法については、以下に説明する方法でも製造可能である。
　即ち、前述の予備製膜試験（予備製膜工程）で得られる図５の結果を活用する方法である。この場合は、図２において、基板温度を３５０℃に、キャリアガスとＴＴＩＰ原料の混合ガスの流量を８００ｓｃｃｍ、酸素ガスの流量を４００ｓｃｃｍに設定し、高周波電力は１．５ＫＷとする。製膜時間は、１０分間とする。この場合は、製膜される非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン４ｃと、結晶質酸化チタン層４ｂは、概ね図５の特性に従うことになる。
　図５に示される酸化チタン膜の構造は、ガラス基板側から順に、非晶質酸化チタン層、非晶質酸化チタンと結晶質酸化チタンの混相、及び結晶質酸化チタンが積層される。非晶質酸化チタン層、及び非晶質酸化チタンと結晶質酸化チタンの混相の２層は、ガラス基板側に下地として、１０～４０ｎｍ程度の厚みで製膜される。即ち、製膜時間が比較的に長い場合は、上層の大部分は結晶質酸化チタン膜である。
　上記の非晶質酸化チタン層の上に製膜される非晶質酸化チタンと結晶質酸化チタンとの混相酸化チタン４ｃを下地とする結晶質酸化チタン膜の製膜速度は、１０ｎｍ／分であるので、製膜時間が１０分間であれば、その膜厚は１００ｎｍとなる。
　この膜厚１００ｎｍの結晶質酸化チタン膜の上に、酸化亜鉛膜を製膜することにより、本発明の第２の実施形態に係わる薄膜太陽電池用基板が得られる。 About the manufacturing method of the board | substrate for thin film solar cells concerning the 2nd Embodiment of this invention shown by the said FIG. 11, it can manufacture also by the method demonstrated below.
That is, this is a method of utilizing the result of FIG. 5 obtained in the preliminary film forming test (preliminary film forming step). In this case, in FIG. 2, the substrate temperature is set to 350 ° C., the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm, the flow rate of the oxygen gas is set to 400 sccm, and the high frequency power is 1.5 kW. The film formation time is 10 minutes. In this case, the mixed phase titanium oxide 4c of amorphous titanium oxide and crystalline titanium oxide to be formed and the crystalline titanium oxide layer 4b generally follow the characteristics shown in FIG.
In the structure of the titanium oxide film shown in FIG. 5, an amorphous titanium oxide layer, a mixed phase of amorphous titanium oxide and crystalline titanium oxide, and crystalline titanium oxide are laminated in order from the glass substrate side. The amorphous titanium oxide layer and two layers of a mixed phase of amorphous titanium oxide and crystalline titanium oxide are formed with a thickness of about 10 to 40 nm as a base on the glass substrate side. That is, when the film forming time is relatively long, most of the upper layer is a crystalline titanium oxide film.
The deposition rate of the crystalline titanium oxide film based on the mixed phase titanium oxide 4c of amorphous titanium oxide and crystalline titanium oxide formed on the amorphous titanium oxide layer is 10 nm / min. Therefore, if the film forming time is 10 minutes, the film thickness is 100 nm.
A thin film solar cell substrate according to the second embodiment of the present invention is obtained by forming a zinc oxide film on the crystalline titanium oxide film having a thickness of 100 nm.
　本実施例では、第１の電極１０１のサイズが長さ１．５ｍｘ幅０．３ｍｘ厚み２０ｍｍであるので、基板サイズは、上記１．５ｍｘ０．２５ｍｘ厚み４ｍｍのガラス基板に、に制約されるが、第１及び第２の電極１０１、１０３からなる一対の電極の個数を増加すれば基板サイズの幅は拡大可能であることは当然のことである。 In the present embodiment, since the size of the first electrode 101 is 1.5 mx width 0.3 mx 20 mm in thickness, the substrate size is limited to the glass substrate of 1.5 mx 0.25 mx 4 mm in thickness. Of course, the width of the substrate size can be increased by increasing the number of the pair of electrodes including the first and second electrodes 101 and 103.
　次に、本発明の第３の実施形態に係わる薄膜太陽電池用基板及びその製造方法について、図１２を参照して説明する。また、図２、図３及び図６を参照する。 Next, a thin film solar cell substrate and a method for manufacturing the same according to a third embodiment of the present invention will be described with reference to FIG. Reference is also made to FIG. 2, FIG. 3 and FIG.
　図１２は、本発明の第３の実施形態に係わる薄膜太陽電池用基板の断面を概略的に示す構造図である。
　図１２において、符号２は、透光性絶縁基板で、例えば厚みが４～５ｍｍのガラス基板である。
　符号３ｃは酸化チタン層で、非晶質酸化チタン及び結晶質酸化チタンが混在した状態にある酸化チタン膜（ここでは、非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン膜と呼ぶ）層４ｃと、結晶質酸化チタン層４ｂの２層から構成される。
　非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン４ｃ及び結晶質酸化チタン層４ｂは、いずれも、前述の、図２に示される高周波プラズマＣＶＤ装置により製膜される。
　符号５は結晶質酸化亜鉛（ＺｎＯ）膜層である。この結晶質酸化亜鉛（ＺｎＯ）膜層は、前述の、図３に示される高周波プラズマＣＶＤ装置により製膜される。また、この結晶質酸化亜鉛（ＺｎＯ）膜層５の製膜は、スパッタ装置を用いてもよい。 FIG. 12 is a structural view schematically showing a cross section of a thin film solar cell substrate according to the third embodiment of the present invention.
In FIG. 12, reference numeral 2 denotes a translucent insulating substrate, for example, a glass substrate having a thickness of 4 to 5 mm.
Reference numeral 3c denotes a titanium oxide layer, which is a titanium oxide film in which amorphous titanium oxide and crystalline titanium oxide are mixed (referred to herein as a mixed phase titanium oxide film of amorphous titanium oxide and crystalline titanium oxide). 4c and a crystalline titanium oxide layer 4b.
The mixed phase titanium oxide 4c and the crystalline titanium oxide layer 4b of amorphous titanium oxide and crystalline titanium oxide are both formed by the above-described high-frequency plasma CVD apparatus shown in FIG.
Reference numeral 5 denotes a crystalline zinc oxide (ZnO) film layer. This crystalline zinc oxide (ZnO) film layer is formed by the above-described high-frequency plasma CVD apparatus shown in FIG. In addition, the crystalline zinc oxide (ZnO) film layer 5 may be formed by using a sputtering apparatus.
　上記図１２に示される本発明の第３の実施形態に係わる薄膜太陽電池用基板の製造方法については、以下に説明する方法により製造可能である。
　即ち、前述の予備製膜試験（予備製膜工程）で得られる図６の結果を活用する方法である。図２において、基板温度を３９０℃に、キャリアガスとＴＴＩＰ原料の混合ガスの流量を８００ｓｃｃｍ、酸素ガスの流量を４００ｓｃｃｍに設定し、高周波電力は１．５ＫＷとする。製膜時間は、５分間とする。この場合は、製膜される非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン層と、結晶質酸化チタン層は、概ね図６の特性に従うことになる。
　図６に示される酸化チタン膜の構造は、ガラス基板側から順に、非晶質酸化チタンと結晶質酸化チタンの混相酸化チタン層４ｃ、及び結晶質酸化チタン４ｂが積層される。非晶質酸化チタン及び結晶質酸化チタンの混相酸化チタン層４ｃは、ガラス基板側に下地として、２０～４０ｎｍ程度の厚みで製膜される。即ち、製膜時間が比較的に長い場合は、上層の大部分は結晶質酸化チタン膜４ｂである。
　上記非晶質酸化チタン及び結晶質酸化チタンとの混相酸化チタン層４ｃを下地に有する結晶質酸化チタン膜の製膜速度は、２０ｎｍ／分であるので、製膜時間が５分間であれば、その膜厚は１００ｎｍとなる。
　この膜厚１００ｎｍの結晶質酸化チタン膜４ｂの上に、酸化亜鉛膜５を製膜することにより、本発明の第３の実施形態に係わる薄膜太陽電池用基板が得られる。
　なお、図１２に示される薄膜太陽電池用基板１ｃにおいて、ガラス２と、非晶質酸化チタン及び結晶質酸化チタンとの混相酸化チタン層４ｃの間に、別途ＳｉＯ２膜を厚み２０～１００ｎｍ程度製膜して、アルカリ成分及び水分のバリア層とすることも可能である。 About the manufacturing method of the board | substrate for thin film solar cells concerning the 3rd Embodiment of this invention shown by the said FIG. 12, it can manufacture with the method demonstrated below.
That is, this is a method of utilizing the result shown in FIG. In FIG. 2, the substrate temperature is set to 390 ° C., the flow rate of the mixed gas of the carrier gas and the TTIP raw material is set to 800 sccm, the flow rate of the oxygen gas is set to 400 sccm, and the high frequency power is 1.5 kW. The film forming time is 5 minutes. In this case, the mixed phase titanium oxide layer of amorphous titanium oxide and crystalline titanium oxide and the crystalline titanium oxide layer to be formed generally follow the characteristics shown in FIG.
In the structure of the titanium oxide film shown in FIG. 6, a mixed phase titanium oxide layer 4c of amorphous titanium oxide and crystalline titanium oxide and a crystalline titanium oxide 4b are laminated in order from the glass substrate side. The mixed phase titanium oxide layer 4c of amorphous titanium oxide and crystalline titanium oxide is formed with a thickness of about 20 to 40 nm as a base on the glass substrate side. That is, when the film formation time is relatively long, most of the upper layer is the crystalline titanium oxide film 4b.
Since the deposition rate of the crystalline titanium oxide film having the mixed phase titanium oxide layer 4c of the amorphous titanium oxide and the crystalline titanium oxide as a base is 20 nm / min, if the deposition time is 5 minutes, The film thickness is 100 nm.
A thin film solar cell substrate according to the third embodiment of the present invention is obtained by forming a zinc oxide film 5 on the crystalline titanium oxide film 4b having a thickness of 100 nm.
In the thin film solar cell substrate 1c shown in FIG. 12, a separate SiO 2 film having a thickness of about 20 to 100 nm is formed between the glass 2 and the mixed phase titanium oxide layer 4c of amorphous titanium oxide and crystalline titanium oxide. It is also possible to form a barrier layer of alkali components and moisture by forming a film.
　以上説明した本発明の第１、第２及び第３の実施形態に係わる薄膜太陽電池用基板及びその製造方法によれば、光透過性絶縁基板上に、非晶質酸化チタンと結晶質酸化チタンと、ＧａあるいはＡｌがドープされた結晶粒径の大きい結晶質酸化亜鉛が積層された薄膜太陽電池用基板を製造可能である。その結果、ナトリウムの拡散防止が可能で、高導電性で、高光透過性で、かつ、凹凸構造を有する薄膜太陽電池用基板を製造可能である。
　この薄膜太陽電池用基板をアモルファスシリコン太陽電池及びタンデム型太陽電池の透明電極として用いることにより、高い光電変換効率を有する太陽電池の製造が可能である。
　また、酸化チタン膜及び酸化亜鉛膜からなる透明電極の製造に安価な有機金属材料を用い、且つ、大面積基板への応用が容易な高周波プラズマＣＶＤ法を用いることが可能であることから、薄膜太陽電池の製造コストの革新的低減が可能である。 According to the thin film solar cell substrate and the manufacturing method thereof according to the first, second, and third embodiments of the present invention described above, the amorphous titanium oxide and the crystalline titanium oxide are formed on the light transmissive insulating substrate. And a substrate for a thin film solar cell in which crystalline zinc oxide having a large crystal grain size doped with Ga or Al is laminated. As a result, it is possible to manufacture a thin film solar cell substrate that can prevent sodium diffusion, has high conductivity, high light transmittance, and has an uneven structure.
By using this thin film solar cell substrate as a transparent electrode of an amorphous silicon solar cell and a tandem solar cell, it is possible to manufacture a solar cell having high photoelectric conversion efficiency.
In addition, it is possible to use an inexpensive organometallic material for the production of a transparent electrode made of a titanium oxide film and a zinc oxide film and to use a high-frequency plasma CVD method that can be easily applied to a large-area substrate. It is possible to innovatively reduce the manufacturing cost of solar cells.

Claims (13)

  1. 　透光性絶縁基板、及び該透光性絶縁基板上に堆積された少なくとも酸化チタン膜層及び酸化亜鉛膜層を含む透明電極層から成る薄膜太陽電池用基板であって、前記酸化チタン膜層は非晶質酸化チタン膜層と結晶質酸化チタン膜層から成る２層構造を有することを特徴とする薄膜太陽電池用基板。 A thin film solar cell substrate comprising a translucent insulating substrate, and a transparent electrode layer including at least a titanium oxide film layer and a zinc oxide film layer deposited on the translucent insulating substrate, wherein the titanium oxide film layer comprises: A thin film solar cell substrate having a two-layer structure comprising an amorphous titanium oxide film layer and a crystalline titanium oxide film layer.
  2. 　透光性絶縁基板、及び該透光性絶縁基板上に堆積された少なくとも酸化チタン膜層及び酸化亜鉛膜層を含む透明電極層から成る薄膜太陽電池用基板であって、前記酸化チタン膜層は非晶質酸化チタン膜層と、非晶質酸化チタン及び微結晶酸化チタンが混在した混相酸化チタン膜層と、結晶質酸化チタン膜層から成る３層構造を有することを特徴とする薄膜太陽電池用基板。 A thin film solar cell substrate comprising a translucent insulating substrate, and a transparent electrode layer including at least a titanium oxide film layer and a zinc oxide film layer deposited on the translucent insulating substrate, wherein the titanium oxide film layer comprises: A thin film solar cell having a three-layer structure comprising an amorphous titanium oxide film layer, a mixed phase titanium oxide film layer in which amorphous titanium oxide and microcrystalline titanium oxide are mixed, and a crystalline titanium oxide film layer Substrate.
  3. 　透光性絶縁基板、及び該透光性絶縁基板上に堆積された少なくとも酸化チタン膜層及び酸化亜鉛膜層を含む透明電極層から成る薄膜太陽電池用基板であって、前記酸化チタン膜層は非晶質酸化チタン及び微結晶酸化チタンが混在した混相酸化チタン膜層と、結晶質酸化チタン膜層から成る２層構造を有することを特徴とする薄膜太陽電池用基板。 A thin film solar cell substrate comprising a translucent insulating substrate, and a transparent electrode layer including at least a titanium oxide film layer and a zinc oxide film layer deposited on the translucent insulating substrate, wherein the titanium oxide film layer comprises: A thin film solar cell substrate comprising a two-layer structure comprising a mixed phase titanium oxide film layer in which amorphous titanium oxide and microcrystalline titanium oxide are mixed, and a crystalline titanium oxide film layer.
  4. 　前記酸化亜鉛膜層は結晶性を有する事を特徴とする請求項１～３のいずれかに記載の薄膜太陽電池用基板。 4. The substrate for a thin film solar cell according to claim 1, wherein the zinc oxide film layer has crystallinity.
  5. 　前記非晶質酸化チタン膜層の厚みは１ｎｍ～１５０ｎｍで、且つ、前記結晶質酸化チタン膜層の厚みは５ｎｍ～２５０ｎｍであることを特徴とする請求項１～３のいずれかに記載の薄膜太陽電池用基板。 4. The thin film according to claim 1, wherein the amorphous titanium oxide film layer has a thickness of 1 nm to 150 nm, and the crystalline titanium oxide film layer has a thickness of 5 nm to 250 nm. Solar cell substrate.
  6. 　前記非晶質酸化チタン及び微結晶酸化チタンが混在した混相酸化チタン膜層の厚みは１０ｎｍ～１００ｎｍであることを特徴とする請求項２あるいは３に記載の薄膜太陽電池用基板。 The thin film solar cell substrate according to claim 2 or 3, wherein the thickness of the mixed phase titanium oxide film layer in which the amorphous titanium oxide and the microcrystalline titanium oxide are mixed is 10 nm to 100 nm.
  7. 　請求項１～６のいずれかに記載の薄膜太陽電池用基板の製造方法であって、前記非晶質酸化チタン膜層、前記結晶質酸化チタン膜層及び前記酸化亜鉛膜層は、いずれも高周波プラズマＣＶＤ装置を用いて製造されることを特徴とする薄膜太陽電池用基板の製造方法。 7. The method for manufacturing a thin film solar cell substrate according to claim 1, wherein the amorphous titanium oxide film layer, the crystalline titanium oxide film layer, and the zinc oxide film layer are all high frequency. A method for producing a thin film solar cell substrate, characterized by being produced using a plasma CVD apparatus.
  8. 　請求項１～６のいずれかに記載の薄膜太陽電池用基板の製造方法であって、前記非晶質酸化チタン膜層及び前記結晶質酸化チタン膜層は高周波プラズマＣＶＤ装置を用いて製造され、且つ、前記酸化亜鉛膜層はスパッタ装置を用いて製造されることを特徴とする薄膜太陽電池用基板の製造方法。 The method for manufacturing a substrate for a thin film solar cell according to any one of claims 1 to 6, wherein the amorphous titanium oxide film layer and the crystalline titanium oxide film layer are manufactured using a high-frequency plasma CVD apparatus, And the said zinc oxide film layer is manufactured using a sputtering device, The manufacturing method of the board | substrate for thin film solar cells characterized by the above-mentioned.
  9. 　請求項１～６のいずれかに記載の薄膜太陽電池用基板の製造方法であって、前記非晶質酸化チタン膜層及び前記結晶質酸化チタン膜層は、前記透光性絶縁基板の温度が２５０～４５０℃で製造され、且つ、前記酸化亜鉛膜層は１５０～４５０℃で製造されることを特徴とする薄膜太陽電池用基板の製造方法。 7. The method for manufacturing a substrate for a thin film solar cell according to claim 1, wherein the amorphous titanium oxide film layer and the crystalline titanium oxide film layer have a temperature of the translucent insulating substrate. A method for manufacturing a substrate for a thin-film solar cell, wherein the substrate is manufactured at 250 to 450 ° C., and the zinc oxide film layer is manufactured at 150 to 450 ° C.
  10. 　請求項１～６のいずれかに記載の薄膜太陽電池用基板の製造方法であって、前記非晶質酸化チタン膜層は前記透光性絶縁基板の温度が２５０℃以下で製造され、且つ、前記結晶質酸化チタン膜層は前記透光性絶縁基板の温度が２５０～４５０℃で、且つ、前記酸化亜鉛膜層は前記透光性絶縁基板の温度が１５０～４５０℃で製造されることを特徴とする薄膜太陽電池用基板の製造方法。 The method for manufacturing a thin-film solar cell substrate according to any one of claims 1 to 6, wherein the amorphous titanium oxide film layer is manufactured at a temperature of the light-transmitting insulating substrate of 250 ° C or less, and The crystalline titanium oxide film layer is manufactured at a temperature of the light transmitting insulating substrate of 250 to 450 ° C., and the zinc oxide film layer is manufactured at a temperature of the light transmitting insulating substrate of 150 to 450 ° C. A method for manufacturing a thin film solar cell substrate.
  11. 　請求項１～６のいずれかに記載の薄膜太陽電池用基板の製造方法であって、前記非晶質酸化チタン膜層及び前記結晶質酸化チタン膜層を高周波プラズマＣＶＤ法で製膜する際に、原料として、少なくともチタニウムテトライソプロポキシドと酸素の混合ガスを用い、且つ、前記透光性絶縁基板の温度が２５０～４５０℃で製造されることを特徴とする薄膜太陽電池用基板の製造方法。 7. The method for producing a thin film solar cell substrate according to claim 1, wherein the amorphous titanium oxide film layer and the crystalline titanium oxide film layer are formed by a high-frequency plasma CVD method. A method for producing a substrate for a thin-film solar cell, wherein at least a mixed gas of titanium tetraisopropoxide and oxygen is used as a raw material, and the temperature of the light-transmitting insulating substrate is 250 to 450 ° C. .
  12. 　請求項１ないし６のいずれかに記載の薄膜太陽電池用基板の製造方法であって、前記非晶質酸化チタン膜層及び前記結晶質酸化チタン膜層の製造の際に、前記透光性絶縁基板の温度を２５０℃～４５０℃に設定し、且つ、原料に少なくともチタニウムテトライソプロポキシドと酸素の混合ガスを用いた高周波プラズマＣＶＤ法を用い、且つ、その堆積初期に形成される非晶質酸化チタン膜層を前記透光性絶縁基板からの不純物のバリア層として用い、且つ、該非晶質酸化チタン膜層を下地として形成される結晶質酸化チタン膜層を酸化亜鉛膜層の製膜の際の下地層に用いることを特徴とする薄膜太陽電池用基板の製造方法。 7. The method for manufacturing a thin-film solar cell substrate according to claim 1, wherein the light-transmitting insulating film is formed when the amorphous titanium oxide film layer and the crystalline titanium oxide film layer are manufactured. An amorphous material formed at the initial stage of deposition using a high-frequency plasma CVD method in which the substrate temperature is set to 250 ° C. to 450 ° C., and at least a mixed gas of titanium tetraisopropoxide and oxygen is used as a raw material. A titanium oxide film layer is used as a barrier layer for impurities from the translucent insulating substrate, and a crystalline titanium oxide film layer formed using the amorphous titanium oxide film layer as a base is formed as a zinc oxide film layer. A method for manufacturing a substrate for a thin film solar cell, characterized by being used for a base layer at the time.
  13. 　請求項１ないし６のいずれかに記載の薄膜太陽電池用基板を備えた薄膜太陽電池であって、光電変換層に少なくとも非晶質シリコンあるいは微結晶シリコンが含まれることを特徴とする薄膜太陽電池。 7. A thin film solar cell comprising the thin film solar cell substrate according to claim 1, wherein the photoelectric conversion layer contains at least amorphous silicon or microcrystalline silicon. .
PCT/JP2009/055623 2008-04-02 2009-03-23 Substrate for thin film solar cell, manufacturing method thereof, and thin film solar cell using thereof WO2009122938A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2008095764A JP2008153714A (en) 2008-04-02 2008-04-02 Substrate for thin film solar cell, manufacturing method therefor, and thin film solar cell using the same
JP2008-095764 2008-04-02

Publications (1)

Publication Number Publication Date
WO2009122938A1 true WO2009122938A1 (en) 2009-10-08

Family

ID=39655479

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2009/055623 WO2009122938A1 (en) 2008-04-02 2009-03-23 Substrate for thin film solar cell, manufacturing method thereof, and thin film solar cell using thereof

Country Status (2)

Country Link
JP (1) JP2008153714A (en)
WO (1) WO2009122938A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105914240A (en) * 2016-06-16 2016-08-31 中国华能集团公司 Solar cell using carbon nanotube transparent electrode

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101338782B1 (en) * 2011-11-29 2014-01-10 엘지이노텍 주식회사 Solar cell and method of fabricating the same
CN103422056A (en) * 2012-05-14 2013-12-04 海洋王照明科技股份有限公司 Conductive thin film, and preparation method and application thereof
GB201314699D0 (en) 2013-08-16 2013-10-02 Pilkington Group Ltd Heat treatable coated glass pane
WO2020068630A1 (en) * 2018-09-24 2020-04-02 First Solar, Inc. Photovoltaic devices with textured tco layers, and methods of making tco stacks

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001015787A (en) * 1999-04-27 2001-01-19 Asahi Glass Co Ltd Substrate with transparent conductive film, manufacturing method therefor, and solar battery
JP2001247314A (en) * 2000-03-07 2001-09-11 Ricoh Co Ltd Method for forming thin film and photoelectric transfer element
JP2005244073A (en) * 2004-02-27 2005-09-08 National Institute Of Advanced Industrial & Technology Solar cell and method for manufacturing the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001015787A (en) * 1999-04-27 2001-01-19 Asahi Glass Co Ltd Substrate with transparent conductive film, manufacturing method therefor, and solar battery
JP2001247314A (en) * 2000-03-07 2001-09-11 Ricoh Co Ltd Method for forming thin film and photoelectric transfer element
JP2005244073A (en) * 2004-02-27 2005-09-08 National Institute Of Advanced Industrial & Technology Solar cell and method for manufacturing the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105914240A (en) * 2016-06-16 2016-08-31 中国华能集团公司 Solar cell using carbon nanotube transparent electrode

Also Published As

Publication number Publication date
JP2008153714A (en) 2008-07-03

Similar Documents

Publication Publication Date Title
Karouta et al. Structural, compositional and optical properties of PECVD silicon nitride layers
US5453135A (en) Photoelectric conversion device with improved back reflection layer
US7883789B2 (en) Substrate with transparent conductive oxide film, process for its production and photoelectric conversion element
US6475354B1 (en) Deposited film producing process, photovoltaic device producing process, and deposited film producing system
EP2333818B1 (en) Transparent conductive film, and transparent electrode comprising same
US5418019A (en) Method for low temperature plasma enhanced chemical vapor deposition (PECVD) of an oxide and nitride antireflection coating on silicon
Sheel et al. Atmospheric pressure chemical vapour deposition of F doped SnO2 for optimum performance solar cells
WO2009122938A1 (en) Substrate for thin film solar cell, manufacturing method thereof, and thin film solar cell using thereof
WO2001065612A1 (en) Photoelectric device
WO2009142187A1 (en) Thin film photoelectric conversion device and method for manufacturing the same
WO2009136530A1 (en) Substrate for thin film solar cell, method for producing the same, and thin film solar cell using the same
CN103000704A (en) Polycrystalline silicon solar cell antireflection film and preparation method thereof
Shin et al. Optimization of intrinsic hydrogenated amorphous silicon deposited by very high-frequency plasma-enhanced chemical vapor deposition using the relationship between Urbach energy and silane depletion fraction for solar cell application
KR20120119734A (en) Zno based transparent conductive thin film for photovoltaic and method of manufacturing thereof
Ismail et al. Synthesis of diamond-like carbon films by electro-deposition technique for solar cell applications
WO2005078154A1 (en) Process for producing transparent conductive film and process for producing tandem thin-film photoelectric converter
US20100320456A1 (en) Method for Fabricating a Doped and/or Alloyed Semiconductor
Yang et al. Effectively improved SiO2‐TiO2 composite films applied in commercial multicrystalline silicon solar cells
JP2000114562A (en) Photoelectric conversion element and manufacture thereof
US20120107491A1 (en) High Permittivity Transparent Films
JP2003188400A (en) Crystalline silicon carbide film and manufacturing method thereof, and solar cell
US20130029123A1 (en) Tin oxide deposited by linear plasma enhanced chemical vapor deposition
Gao et al. Nanocrystalline Si: H thin films grown at room temperature with plasma-enhanced chemical vapour deposition at a very high pressure
Srujana et al. Zirconium doped zinc oxide thin films grown by spray pyrolysis technique for TCO applications
Abramov et al. Addition of SiF4 to standard SiH4+ H2 plasma: an effective way to reduce oxygen contamination in μc‐Si: H films

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09726714

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09726714

Country of ref document: EP

Kind code of ref document: A1