WO2010082120A1 - Amorphous carbon, method of manufacturing the same, and solar cell including the same - Google Patents

Amorphous carbon, method of manufacturing the same, and solar cell including the same Download PDF

Info

Publication number
WO2010082120A1
WO2010082120A1 PCT/IB2010/000062 IB2010000062W WO2010082120A1 WO 2010082120 A1 WO2010082120 A1 WO 2010082120A1 IB 2010000062 W IB2010000062 W IB 2010000062W WO 2010082120 A1 WO2010082120 A1 WO 2010082120A1
Authority
WO
WIPO (PCT)
Prior art keywords
amorphous carbon
chamber
substrate
atomic percent
material gas
Prior art date
Application number
PCT/IB2010/000062
Other languages
French (fr)
Inventor
Seiji Yamashita
Kenichi Okumura
Taizo Masuda
Masayoshi Umeno
Hideo Uchida
Sudip Adhikari
Dilip Ghimire Chandra
Original Assignee
Toyota Jidosha Kabushiki Kaisha
Chubu University Educational Foundation
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 Toyota Jidosha Kabushiki Kaisha, Chubu University Educational Foundation filed Critical Toyota Jidosha Kabushiki Kaisha
Publication of WO2010082120A1 publication Critical patent/WO2010082120A1/en

Links

Classifications

    • 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
    • H01L31/20—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof such devices or parts thereof comprising amorphous semiconductor materials
    • H01L31/202—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof such devices or parts thereof comprising amorphous semiconductor materials including only elements of Group IV of the Periodic Table
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • 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
    • C23C16/26—Deposition of carbon only
    • 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
    • C23C16/44—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 method of coating
    • C23C16/50—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 method of coating using electric discharges
    • C23C16/511—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 method of coating using electric discharges using microwave discharges
    • 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
    • H01L31/04—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 adapted as photovoltaic [PV] conversion devices
    • 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
    • Y02E10/547—Monocrystalline silicon PV cells
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the invention relates to amorphous carbon, a method of manufacturing the amorphous carbon, and a solar cell including the amorphous carbon.
  • Amorphous carbon used in a photoelectric element has been available, as described in, for example, Japanese Patent Application Publication No. 2003-209270 (JP-A-2003-209270).
  • the amorphous carbon is formed by irradiating an outermost surface of a nano-carbon molecular layer with laser light to change the structure of the nano-carbon molecular layer.
  • the amorphous carbon contains sp2-bonded carbon atoms and sp3-bonded carbon atoms, and therefore, the structure of the amorphous carbon is complicated. Thus, it is difficult to realize the amorphous carbon that functions as a p-type semiconductor or an n-type semiconductor in the related art.
  • the amorphous carbon layer in the photoelectric element described in the publication No. 2003-209270 constitutes a p-type semiconductor layer.
  • the electrical resistivity of the amorphous carbon layer is high. More specifically, the electrical resistivity of the amorphous carbon layer is approximately 20 k ⁇ -cm. Therefore, if the amorphous carbon layer is used in, for example, a solar cell, it is difficult to extract sufficient current from the solar cell because of high electrical resistivity, and thus, the power generation efficiency of the solar cell is low.
  • the invention provides amorphous carbon with low electrical resistivity, a method of manufacturing the amorphous carbon, and a solar cell with high efficiency, which includes the amorphous carbon.
  • amorphous carbon with low electrical resistivity is manufactured by specifying a concentration of hydrogen that satisfies a predetermined condition, and the invention has been made based on the finding.
  • Amorphous carbon according to a first aspect of the invention contains hydrogen at a concentration in a range of 5 atomic percent to 30 atomic percent, and a doping element.
  • the doping element may be boron
  • the doping element may be nitrogen.
  • a concentration of the doping element may be 10 atomic percent or lower.
  • the concentration of the hydrogen may be in a range of 17 atomic percent to 27 atomic percent.
  • a method of manufacturing amorphous carbon according to a second aspect of the invention includes producing plasma of a raw material gas in a chamber, and forming amorphous carbon on a substrate placed in the chamber using the plasma.
  • a distance from a generation portion, on which the plasma is generated, to the substrate is set to be in a range of 0.5 cm to 10 cm, and a temperature of the substrate is set to be in a range of 250 0 C to 500 0 C.
  • the second aspect of the invention it is possible to manufacture the amorphous carbon with low electrical resistivity at relatively low cost by setting the distance from the generation portion, on which the plasma is generated, to the substrate to a value in the range of 0.5 cm to 10 cm, and setting the substrate temperature to a value in the range of 250 0 C to 500 0 C.
  • a solar cell according to a third aspect of the invention includes the amorphous carbon according to the first aspect of the invention.
  • the solar cell according to the third aspect of the invention it is possible to reduce dangling bonds by setting the hydrogen concentration to a value that is not extremely low (for example, by setting the hydrogen concentration to 5 atomic percent or higher), and thus, it is possible to improve the efficiency of the solar cell.
  • FIG. 1 schematically shows the configuration of an apparatus used in a method of manufacturing amorphous carbon according to an embodiment of the invention
  • FIG. 2 is a table showing manufacturing conditions for the amorphous carbon according the embodiment of the invention.
  • FIG. 3 is a table showing physical properties of the amorphous carbon manufactured under the manufacturing conditions shown in FIG. 2.
  • Amorphous carbon and a method of manufacturing the amorphous carbon according to an embodiment of the invention will be described in detail with reference to the attached drawings.
  • the amorphous carbon according to the embodiment contains hydrogen at a concentration in a range of 5 atomic percent to 30 atomic percent, and is doped with a doping element.
  • the main component of the amorphous carbon is, for example, carbon.
  • the amorphous carbon contains carbon atoms bonded in two different structures, that is, sp2-bonded carbon atoms and sp3-bonded carbon atoms.
  • the concentration of hydrogen, which is one of the components of the amorphous carbon is set to be in a range of 5 atomic percent to 30 atomic percent.
  • the hydrogen concentration may be set to be in a range of 17 atomic percent to 27 atomic percent, or in a range of 20 atomic percent to 25 atomic percent.
  • the hydrogen concentration is set to a value that is not extremely low (i.e., by setting the hydrogen concentration to 5 atomic percent or higher), it is possible to suppress a decrease in the efficiency of a solar cell due to an increase in dangling bonds.
  • a concentration of the doping element may be 10% or lower. Further, the concentration of the doping element may be 6% or lower.
  • the sp2/sp3 bonding ratio may be set to be in a range of 0.5 to 5.
  • FIG. .1 is a side cross-sectional view showing the configuration of a plasma chemical vapor deposition (CVD) apparatus 10, which is used in manufacture of the amorphous carbon according to the embodiment. As shown in FIG. 1, the plasma CVD apparatus 10 includes a chamber 11, a raw material gas source 12, a waveguide channel 14, and a microwave generation portion 15.
  • the chamber 11 is an airtight container in which plasma P of a raw material gas G is produced.
  • the chamber 11 is connected to the raw material gas source 12 through a pipe 22.
  • the raw material gas source 12 supplies the raw material gas G to the chamber 11.
  • the raw material gas source 12 and the pipe 22 function as a raw material gas supply portion.
  • Exhaust means 13 includes an exhaust pump, and is provided near an exhaust port 19 of the chamber 11. Before an amorphous carbon membrane is grown, the exhaust means 13 reduces the pressure in the chamber 11 by vacuuming.
  • a substrate B is placed in the chamber 11 so that amorphous carbon C is grown on the substrate B.
  • a substrate temperature control portion (not shown), which controls the temperature of the substrate B, is provided for the substrate B. The temperature of the substrate B is controlled to a predetermined temperature by the substrate temperature control portion.
  • the temperature of the substrate B may be set to be in a range of 250 0 C to 500 0 C, or in a range of 300 0 C to 400 0 C. Further, the temperature of the substrate B may be set to be in a range of 350 0 C to 380 0 C.
  • a substrate stage 18, which supports the substrate B, is provided in the chamber 11.
  • the microwave generation portion 15 generates a microwave W and outputs the microwave W to the chamber 11 through the waveguide channel 14 so that the raw material gas G in the chamber 11 is irradiated with the microwave W.
  • the microwave W is used for changing the raw material gas G, which has been introduced into the chamber 11, into the plasma P.
  • the microwave generation portion 15 includes, for example, a magnetron.
  • the microwave generation portion 15 generates the microwave W with an output of 600 [W] to 1400 [W] and a frequency of 2.45 GHz, using the magnetron.
  • the microwave W generated by the microwave generation portion 15 has a pulse frequency, and the pulse frequency and a duty ratio are controlled to predetermined values.
  • the waveguide channel 14 guides the microwave W output from the microwave generation portion 15 toward the chamber 11 so that the microwave W is introduced into the chamber 11.
  • the waveguide channel 14 is provided above the chamber 11 in a manner such that a quartz window 16 is provided between the waveguide channel 14 and the chamber 11.
  • a slot antenna 17 is provided on a surface of the waveguide channel 14, which faces the chamber 11.
  • the raw material gas G in the chamber 11 is irradiated with the microwave W through the slot antenna 17.
  • Cooling fans 20 are provided on the waveguide channel 14 in order to cool the waveguide channel 14.
  • the quartz window 16 constitutes a surface on which the plasma P is produced, and may function as a generation portion on which the plasma P is generated.
  • the raw material gas source 12 supplies the raw material gas G to the chamber 11 in order to grow the amorphous carbon C on the substrate B.
  • the raw material gas G contains a material gas containing carbon atoms, a dopant gas containing the doping element (dopant) that serves as an impurity element, and a carrier gas. More specifically, the raw material gas source 12 includes, as a source of the material gas, at least one of methane (CH 4 ), ethylene (C 2 H 4 ), and acetylene (C 2 H 2 ).
  • the raw material gas source 12 includes, for example, trimethylboron (B(CH 3 ) 3 ) and/or nitrogen (N 2 ) as (a) source(s) of the dopant gas. It should be noted that the nitrogen is omitted in FIG. 1.
  • Trimethylboron is the dopant gas used to dope the amorphous carbon with boron, which serves as the doping element.
  • the use of trimethylboron makes it possible to manufacture the boron-doped amorphous carbon.
  • nitrogen (N 2 ) is the dopant gas used to dope the amorphous carbon with nitrogen (N), which serves as the doping element.
  • nitrogen (N 2 ) makes it possible to manufacture the nitrogen (N)-doped amorphous carbon. .
  • By doping the amorphous .carbon 'with nitrogen (N), it is possible to manufacture n-type amorphous carbon that exhibits physical properties of an n-type semiconductor, on the condition that the hydrogen concentration is in a predetermined range.
  • the raw material gas source 12 includes a source of an inactive gas, such as argon (Ar), as a carrier gas source.
  • the raw material gas source 12 is connected to the chamber 11 through mass flow controllers (MFC; not shown) that adjust flow amounts of the respective gases.
  • MFC mass flow controllers
  • the material gas, the dopant gas, and the carrier gas flow through the respective mass flow controllers, and then the gases are mixed together and supplied to the chamber 11 as the raw material gas G.
  • the substrate B is placed in the chamber 11 at a predetermined distance d from the quartz window 16, which functions as the generation portion on which the plasma P is generated.
  • the distance from the generation portion , on which the plasma P is generated, to the substrate B is set to the distance d. Further, the distance d can be changed by changing the position at which the substrate B is disposed.
  • the distance d may be set to be in a range of 0.5 cm to 10 cm, or in a range of 0.5 cm to 5cm. Further, the distance d may be set to be in a range of 1 cm to 3 cm.
  • the substrate B may be disposed near or in a region in which the plasma P exists. By disposing the substrate B at a position as described above, it is possible to improve an effect of etching a defect of the amorphous carbon.
  • the substrate B is placed on the substrate stage 18 in the chamber 11. Then, the pressure in the chamber 11 is reduced. After the pressure in the chamber 11 is reduced, the raw material gas G that contains the material gas, such as methane, ethylene, and/or acetylene, the dopant gas, such as trimethylboron or nitrogen, and the carrier gas, such as argon, is supplied from the raw material gas source 12 into the chamber 11. While the raw material gas G is supplied into the chamber 11, the microwave generation portion 15 generates the microwave W, and the raw material gas G in the chamber 11 is irradiated with the generated microwave W. During this process, the flow amount of each raw material gas supplied to the chamber 11 is accurately controlled by the corresponding mass flow controller.
  • the material gas source 12 such as methane, ethylene, and/or acetylene
  • the dopant gas such as trimethylboron or nitrogen
  • the carrier gas such as argon
  • the microwave W output from the microwave generation portion 15 is guided by the waveguide channel 14 toward the chamber 11, and the raw material gas G in the chamber 11 is irradiated with the microwave W. Accordingly, surface wave plasma P is produced in the chamber 11.
  • the raw material gas G is changed into radicals containing carbon, and the radicals are moved to the surface of the substrate B and deposited thereon.
  • the temperature of the substrate B is controlled to the predetermined temperature by the substrate temperature control portion.
  • the plasma P is deposited on the substrate B, and accordingly, the amorphous carbon C is grown on the substrate B. In this way, the amorphous carbon C is manufactured.
  • the apparatus and method for manufacturing the amorphous carbon according to the embodiment of the invention has been described.
  • the apparatus and method for manufacturing the amorphous carbon according to the invention are not limited to those in the above-embodiment, and modifications may be made to the above-described embodiment in the scope of the invention.
  • the plasma CVD apparatus 10 may be provided with a bias power source for applying voltage between the plasma P and the substrate B.
  • the amorphous carbon manufactured by the plasma CVD and the method for manufacturing the amorphous carbon by the plasma CVD have been described.
  • the amorphous carbon according to the invention may be manufactured by physical vapor deposition (PVD).
  • FIG. 2 is a table showing the manufacturing conditions under which the amorphous carbon was manufactured in the examples described below
  • FIG. 3 is a table showing the physical properties, etc. of the amorphous carbon manufactured under the manufacturing conditions shown in FIG. 2.
  • the distance d from the generation portion , on which the plasma P is generated, to the substrate B will be referred to as a substrate distance.
  • Example 1 As shown in FIG. 2, the amorphous carbon was manufactured using the apparatus and method for manufacturing the amorphous carbon according to the embodiment as described above.
  • the flow amounts of the raw material gases that is, the flow amounts of argon, acetylene, and trimethylboron were set to 200 seem, 50 seem, and 30 seem, respectively.
  • the conditions relating to the microwave W used in the example 1 were set so that the output was 1000 W, the operating frequency was 500 Hz, and the duty ratio (i.e., the ratio of "on") was 30%.
  • the pressure in the chamber 11 was set to 50 Pa
  • the substrate temperature was set to 400 0 C
  • the substrate distance was set to 1 cm
  • the deposition time was set to 30 minutes.
  • Trimethylboron was diluted with argon at a dilution ratio of 1:99 (i.e., a ratio between trimethylboron and argon was 1:99), and the diluted trimethylboron was supplied to the chamber 11.
  • the above-described flow amount of trimethylboron is the flow amount of trimethylboron diluted with argon.
  • the hydrogen concentration was 26.4 atomic percent
  • the boron concentration was 1.06 atomic percent in the manufactured amorphous carbon, as shown in FIG. 3.
  • the electrical resistivity of the manufactured amorphous carbon was 2.99 ⁇ ⁇ cm, and the manufactured amorphous carbon exhibited p-type conductivity.
  • Example 2 In the example 2, nitrogen (N 2 ) was supplied to the chamber 11, instead of trimethylboron used in the example 1, and the flow amount of nitrogen (N 2 ) supplied was 10 seem.
  • Other manufacturing conditions were the same as those in the example 1.
  • the hydrogen concentration was 17 atomic percent
  • the nitrogen (N) concentration was 5.82 atomic percent in the manufactured amorphous carbon, as shown in FIG. 3.
  • the electrical resistivity of the manufactured amorphous carbon was 4.55 ⁇ -cm, and the manufactured amorphous carbon exhibited n-type conductivity.
  • the defect density of the amorphous carbon was 10 21 cm “3 or higher, and the amorphous carbon did not exhibit either p-type conductivity or n-type conductivity.

Landscapes

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

Abstract

Amorphous carbon according to the invention contains hydrogen at a concentration in a range of 5 atomic percent to 30 atomic percent, and a doping element. It exhibits a low electrical resistivity.

Description

AMORPHOUS CARBON, METHOD OF MANUFACTURING THE SAME, AND
SOLAR CELL INCLUDING THE SAME
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0001] The invention relates to amorphous carbon, a method of manufacturing the amorphous carbon, and a solar cell including the amorphous carbon.
2. Description of the Related Art
[0002] Amorphous carbon used in a photoelectric element has been available, as described in, for example, Japanese Patent Application Publication No. 2003-209270 (JP-A-2003-209270). The amorphous carbon is formed by irradiating an outermost surface of a nano-carbon molecular layer with laser light to change the structure of the nano-carbon molecular layer.
[0003] There are two carbon bonding structures, that is, the sp2 bonding structure and the sp3 bonding structure. The amorphous carbon contains sp2-bonded carbon atoms and sp3-bonded carbon atoms, and therefore, the structure of the amorphous carbon is complicated. Thus, it is difficult to realize the amorphous carbon that functions as a p-type semiconductor or an n-type semiconductor in the related art.
[0004] The amorphous carbon layer in the photoelectric element described in the publication No. 2003-209270 constitutes a p-type semiconductor layer. However, the electrical resistivity of the amorphous carbon layer is high. More specifically, the electrical resistivity of the amorphous carbon layer is approximately 20 kΩ-cm. Therefore, if the amorphous carbon layer is used in, for example, a solar cell, it is difficult to extract sufficient current from the solar cell because of high electrical resistivity, and thus, the power generation efficiency of the solar cell is low. SUMMARY OF THE INVENTION
[0005] The invention provides amorphous carbon with low electrical resistivity, a method of manufacturing the amorphous carbon, and a solar cell with high efficiency, which includes the amorphous carbon. [0006] As a result of dedicated research, the inventors have found that amorphous carbon with low electrical resistivity is manufactured by specifying a concentration of hydrogen that satisfies a predetermined condition, and the invention has been made based on the finding.
[0007] Amorphous carbon according to a first aspect of the invention contains hydrogen at a concentration in a range of 5 atomic percent to 30 atomic percent, and a doping element.
[0008] According to the first aspect of the invention, it is possible to manufacture the amorphous carbon with low electrical resistivity.
[0009] In the amorphous carbon according to the first aspect of the invention, the doping element may be boron.
[0010] This makes it possible to manufacture the p-type amorphous carbon with low electrical resistivity.
[0011] In the amorphous carbon according to the first aspect of the invention, the doping element may be nitrogen. [0012] This makes it possible to manufacture the n-type amorphous carbon with low electrical resistivity.
[0013] In the amorphous carbon according to the first aspect of the invention, a concentration of the doping element may be 10 atomic percent or lower.
[0014] This makes it possible to manufacture the amorphous carbon with further improved electric conductivity.
[0015] In the amorphous carbon according to the first aspect of the invention, the concentration of the hydrogen may be in a range of 17 atomic percent to 27 atomic percent.
[0016] This makes it possible to manufacture the amorphous carbon with electrical resistivity that is much lower than the electrical resistivity of amorphous carbon in the related art.
• [0017] A method of manufacturing amorphous carbon according to a second aspect of the invention includes producing plasma of a raw material gas in a chamber, and forming amorphous carbon on a substrate placed in the chamber using the plasma. In the method, a distance from a generation portion, on which the plasma is generated, to the substrate is set to be in a range of 0.5 cm to 10 cm, and a temperature of the substrate is set to be in a range of 250 0C to 500 0C.
[0018] According to the second aspect of the invention, it is possible to manufacture the amorphous carbon with low electrical resistivity at relatively low cost by setting the distance from the generation portion, on which the plasma is generated, to the substrate to a value in the range of 0.5 cm to 10 cm, and setting the substrate temperature to a value in the range of 250 0C to 500 0C.
[0019] A solar cell according to a third aspect of the invention includes the amorphous carbon according to the first aspect of the invention.
[0020] In the solar cell according to the third aspect of the invention, it is possible to reduce dangling bonds by setting the hydrogen concentration to a value that is not extremely low (for example, by setting the hydrogen concentration to 5 atomic percent or higher), and thus, it is possible to improve the efficiency of the solar cell. [0021] According to the invention, it is possible to provide the amorphous carbon with low electrical resistivity, a method of manufacturing the amorphous carbon, and the solar cell with high efficiency, which includes the amorphous carbon.
BRIEF DESCRIPTION OF THE DRAWINGS [0022] The foregoing and further features and advantages of the invention will become apparent from the following description of example embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements, and wherein:
FIG. 1 schematically shows the configuration of an apparatus used in a method of manufacturing amorphous carbon according to an embodiment of the invention;
FIG. 2 is a table showing manufacturing conditions for the amorphous carbon according the embodiment of the invention; and
FIG. 3 is a table showing physical properties of the amorphous carbon manufactured under the manufacturing conditions shown in FIG. 2.
DETAILED DESCRIPTION OF EMBODIMENT
[0023] Amorphous carbon and a method of manufacturing the amorphous carbon according to an embodiment of the invention will be described in detail with reference to the attached drawings.
[0024] The amorphous carbon according to the embodiment contains hydrogen at a concentration in a range of 5 atomic percent to 30 atomic percent, and is doped with a doping element. The main component of the amorphous carbon is, for example, carbon. The amorphous carbon contains carbon atoms bonded in two different structures, that is, sp2-bonded carbon atoms and sp3-bonded carbon atoms. Further, the concentration of hydrogen, which is one of the components of the amorphous carbon, is set to be in a range of 5 atomic percent to 30 atomic percent. The hydrogen concentration may be set to be in a range of 17 atomic percent to 27 atomic percent, or in a range of 20 atomic percent to 25 atomic percent. By setting the hydrogen concentration as described above, it is possible to manufacture the amorphous carbon with low electrical resistivity.
Further, by setting the hydrogen concentration to a value that is not extremely low (i.e., by setting the hydrogen concentration to 5 atomic percent or higher), it is possible to suppress a decrease in the efficiency of a solar cell due to an increase in dangling bonds.
[0025] Further, in the amorphous carbon according to the embodiment, a concentration of the doping element may be 10% or lower. Further, the concentration of the doping element may be 6% or lower. By setting the doping element concentration as described above, it is possible to manufacture the amorphous carbon that exhibits further improved electric conductivity. In the amorphous carbon according to the invention, the sp2/sp3 bonding ratio may be set to be in a range of 0.5 to 5. [0026] FIG. .1 is a side cross-sectional view showing the configuration of a plasma chemical vapor deposition (CVD) apparatus 10, which is used in manufacture of the amorphous carbon according to the embodiment. As shown in FIG. 1, the plasma CVD apparatus 10 includes a chamber 11, a raw material gas source 12, a waveguide channel 14, and a microwave generation portion 15.
[0027] The chamber 11 is an airtight container in which plasma P of a raw material gas G is produced. The chamber 11 is connected to the raw material gas source 12 through a pipe 22. The raw material gas source 12 supplies the raw material gas G to the chamber 11. The raw material gas source 12 and the pipe 22 function as a raw material gas supply portion.
[0028] Exhaust means 13 includes an exhaust pump, and is provided near an exhaust port 19 of the chamber 11. Before an amorphous carbon membrane is grown, the exhaust means 13 reduces the pressure in the chamber 11 by vacuuming. A substrate B is placed in the chamber 11 so that amorphous carbon C is grown on the substrate B. A substrate temperature control portion (not shown), which controls the temperature of the substrate B, is provided for the substrate B. The temperature of the substrate B is controlled to a predetermined temperature by the substrate temperature control portion. The temperature of the substrate B may be set to be in a range of 2500C to 5000C, or in a range of 3000C to 4000C. Further, the temperature of the substrate B may be set to be in a range of 3500C to 3800C. A substrate stage 18, which supports the substrate B, is provided in the chamber 11.
[0029] The microwave generation portion 15 generates a microwave W and outputs the microwave W to the chamber 11 through the waveguide channel 14 so that the raw material gas G in the chamber 11 is irradiated with the microwave W. The microwave W is used for changing the raw material gas G, which has been introduced into the chamber 11, into the plasma P. The microwave generation portion 15 includes, for example, a magnetron. For example, the microwave generation portion 15 generates the microwave W with an output of 600 [W] to 1400 [W] and a frequency of 2.45 GHz, using the magnetron. The microwave W generated by the microwave generation portion 15 has a pulse frequency, and the pulse frequency and a duty ratio are controlled to predetermined values. By controlling the frequency and the duty ratio of the microwave W, it is possible to significantly change the state of the plasma P. Therefore, it is possible to easily control the physical properties of the amorphous carbon manufactured. [0030] The waveguide channel 14 guides the microwave W output from the microwave generation portion 15 toward the chamber 11 so that the microwave W is introduced into the chamber 11. The waveguide channel 14 is provided above the chamber 11 in a manner such that a quartz window 16 is provided between the waveguide channel 14 and the chamber 11. A slot antenna 17 is provided on a surface of the waveguide channel 14, which faces the chamber 11. The raw material gas G in the chamber 11 is irradiated with the microwave W through the slot antenna 17. Cooling fans 20 are provided on the waveguide channel 14 in order to cool the waveguide channel 14. The quartz window 16 constitutes a surface on which the plasma P is produced, and may function as a generation portion on which the plasma P is generated. [0031] The raw material gas source 12 supplies the raw material gas G to the chamber 11 in order to grow the amorphous carbon C on the substrate B. The raw material gas G contains a material gas containing carbon atoms, a dopant gas containing the doping element (dopant) that serves as an impurity element, and a carrier gas. More specifically, the raw material gas source 12 includes, as a source of the material gas, at least one of methane (CH4), ethylene (C2H4), and acetylene (C2H2).
[0032] Further, for example, the raw material gas source 12 includes, for example, trimethylboron (B(CH3)3) and/or nitrogen (N2) as (a) source(s) of the dopant gas. It should be noted that the nitrogen is omitted in FIG. 1.
[0033] Trimethylboron is the dopant gas used to dope the amorphous carbon with boron, which serves as the doping element. The use of trimethylboron makes it possible to manufacture the boron-doped amorphous carbon. By doping the amorphous carbon with boron, it is possible to manufacture p-type amorphous carbon that exhibits physical properties of a p-type semiconductor, on the condition that the hydrogen concentration is in a predetermined range. [0034] Further, nitrogen (N2) is the dopant gas used to dope the amorphous carbon with nitrogen (N), which serves as the doping element. The use of nitrogen (N2) makes it possible to manufacture the nitrogen (N)-doped amorphous carbon. . By doping the amorphous .carbon 'with nitrogen (N),, it is possible to manufacture n-type amorphous carbon that exhibits physical properties of an n-type semiconductor, on the condition that the hydrogen concentration is in a predetermined range.
[0035] Further, the raw material gas source 12 includes a source of an inactive gas, such as argon (Ar), as a carrier gas source. The raw material gas source 12 is connected to the chamber 11 through mass flow controllers (MFC; not shown) that adjust flow amounts of the respective gases. The material gas, the dopant gas, and the carrier gas flow through the respective mass flow controllers, and then the gases are mixed together and supplied to the chamber 11 as the raw material gas G.
[0036] In the plasma CVD apparatus 10 thus configured, the substrate B is placed in the chamber 11 at a predetermined distance d from the quartz window 16, which functions as the generation portion on which the plasma P is generated. In other words, the distance from the generation portion , on which the plasma P is generated, to the substrate B is set to the distance d. Further, the distance d can be changed by changing the position at which the substrate B is disposed.
[0037] The distance d may be set to be in a range of 0.5 cm to 10 cm, or in a range of 0.5 cm to 5cm. Further, the distance d may be set to be in a range of 1 cm to 3 cm. In other words, the substrate B may be disposed near or in a region in which the plasma P exists. By disposing the substrate B at a position as described above, it is possible to improve an effect of etching a defect of the amorphous carbon.
[0038] Next, operations of an apparatus, and a method of manufacturing the amorphous carbon according to the embodiment will be described.
[0039] In FIG. 1, first, the substrate B is placed on the substrate stage 18 in the chamber 11. Then, the pressure in the chamber 11 is reduced. After the pressure in the chamber 11 is reduced, the raw material gas G that contains the material gas, such as methane, ethylene, and/or acetylene, the dopant gas, such as trimethylboron or nitrogen, and the carrier gas, such as argon, is supplied from the raw material gas source 12 into the chamber 11. While the raw material gas G is supplied into the chamber 11, the microwave generation portion 15 generates the microwave W, and the raw material gas G in the chamber 11 is irradiated with the generated microwave W. During this process, the flow amount of each raw material gas supplied to the chamber 11 is accurately controlled by the corresponding mass flow controller.
[0040] The microwave W output from the microwave generation portion 15 is guided by the waveguide channel 14 toward the chamber 11, and the raw material gas G in the chamber 11 is irradiated with the microwave W. Accordingly, surface wave plasma P is produced in the chamber 11. Thus, the raw material gas G is changed into radicals containing carbon, and the radicals are moved to the surface of the substrate B and deposited thereon. During this process, the temperature of the substrate B is controlled to the predetermined temperature by the substrate temperature control portion.
[0041] Then, the plasma P is deposited on the substrate B, and accordingly, the amorphous carbon C is grown on the substrate B. In this way, the amorphous carbon C is manufactured.
[0042] The apparatus and method for manufacturing the amorphous carbon according to the embodiment of the invention has been described. However, the apparatus and method for manufacturing the amorphous carbon according to the invention are not limited to those in the above-embodiment, and modifications may be made to the above-described embodiment in the scope of the invention. For example, the plasma CVD apparatus 10 may be provided with a bias power source for applying voltage between the plasma P and the substrate B.
[0043] Further, in the above-described embodiment, the amorphous carbon manufactured by the plasma CVD, and the method for manufacturing the amorphous carbon by the plasma CVD have been described. However, the amorphous carbon according to the invention may be manufactured by physical vapor deposition (PVD).
[0044] The invention will be hereinafter more specifically described based on examples and comparative examples below. However, it should be noted that the invention is not limited to the examples described below. FIG. 2 is a table showing the manufacturing conditions under which the amorphous carbon was manufactured in the examples described below, and FIG. 3 is a table showing the physical properties, etc. of the amorphous carbon manufactured under the manufacturing conditions shown in FIG. 2. Further, in the description below, the distance d from the generation portion , on which the plasma P is generated, to the substrate B will be referred to as a substrate distance.
[0045] (Example 1) As shown in FIG. 2, the amorphous carbon was manufactured using the apparatus and method for manufacturing the amorphous carbon according to the embodiment as described above. In the example 1, the flow amounts of the raw material gases, that is, the flow amounts of argon, acetylene, and trimethylboron were set to 200 seem, 50 seem, and 30 seem, respectively. Further, the conditions relating to the microwave W used in the example 1 were set so that the output was 1000 W, the operating frequency was 500 Hz, and the duty ratio (i.e., the ratio of "on") was 30%. Further, the pressure in the chamber 11 was set to 50 Pa, the substrate temperature was set to 400 0C, the substrate distance was set to 1 cm, and the deposition time was set to 30 minutes. Trimethylboron was diluted with argon at a dilution ratio of 1:99 (i.e., a ratio between trimethylboron and argon was 1:99), and the diluted trimethylboron was supplied to the chamber 11. The above-described flow amount of trimethylboron is the flow amount of trimethylboron diluted with argon. [0046] As a result of manufacturing the amorphous carbon under the manufacturing conditions as described above, the hydrogen concentration was 26.4 atomic percent, and the boron concentration was 1.06 atomic percent in the manufactured amorphous carbon, as shown in FIG. 3. The electrical resistivity of the manufactured amorphous carbon was 2.99 Ω ■ cm, and the manufactured amorphous carbon exhibited p-type conductivity. [0047] (Example 2) In the example 2, nitrogen (N2) was supplied to the chamber 11, instead of trimethylboron used in the example 1, and the flow amount of nitrogen (N2) supplied was 10 seem. Other manufacturing conditions were the same as those in the example 1. As a result of manufacturing the amorphous carbon under the manufacturing conditions as described above, the hydrogen concentration was 17 atomic percent, and the nitrogen (N) concentration was 5.82 atomic percent in the manufactured amorphous carbon, as shown in FIG. 3. The electrical resistivity of the manufactured amorphous carbon was 4.55 Ω-cm, and the manufactured amorphous carbon exhibited n-type conductivity. [0048] In the above-described examples, it was possible to adjust the hydrogen concentration in the manufactured amorphous carbon, by setting the substrate distance d to the predetermined distance and the substrate temperature to the predetermined temperature. Further, it has been confirmed that it is possible to manufacture p-type amorphous carbon and n-type amorphous carbon that exhibit electrical resistivity (10 Ω-cm or lower) much lower than that of the amorphous carbon in the related art, by adjusting the hydrogen concentration to the predetermined hydrogen concentration, and doping the amorphous carbon with the doping element.
[0049] (Comparative example 1) When the hydrogen concentration in the boron-doped amorphous carbon, which contains boron as the doping element, was 46.2 atomic percent, the electrical resistivity of the amorphous carbon was 106 Ω-cm or higher, and the amorphous carbon did not exhibit either p-type conductivity or n-type conductivity.
[0050] (Comparative example 2) When the hydrogen concentration in the nitrogen-doped amorphous carbon, which contains nitrogen as the doping element, was 36.6 atomic percent, the electrical resistivity of the amorphous carbon was 106 Ω-cm or higher, and the amorphous carbon did not exhibit either p-type conductivity or n-type conductivity.
[0051] (Comparative example 3) When the hydrogen concentration in the nitrogen-doped amorphous carbon, which contains nitrogen as the doping element, was 53.3 atomic percent, the electrical resistivity of the amorphous carbon was 106 Ω-cm or higher, and the amorphous carbon did not exhibit either p-type conductivity or n-type conductivity.
[0052] (Comparative example 4) When the hydrogen concentration in the nitrogen-doped amorphous carbon, which contains nitrogen as the doping element, was 50.0 atomic percent, the electrical resistivity of the amorphous carbon was 106 Ω-cm or higher, and the amorphous carbon did not exhibit either p-type conductivity or n-type conductivity.
[0053] (Comparative example 5) When the hydrogen concentration in the nitrogen-doped amorphous carbon, which contains nitrogen as the doping element, was
1.6 atomic percent, the defect density of the amorphous carbon was 1021 cm"3 or higher, and the amorphous carbon did not exhibit either p-type conductivity or n-type conductivity.
[0054] On the basis of the results of the above-described comparative examples, it has been confirmed that, if the hydrogen concentration is outside the ranges defined in the invention, the electrical resistivity of the amorphous carbon becomes high, and the amorphous carbon does not exhibit either p-type conductivity or n-type conductivity.

Claims

1. Amorphous carbon characterized by containing: hydrogen at a concentration in a range of 5 atomic percent to 30 atomic percent; and a doping element.
2. The amorphous carbon according to claim 1, wherein the doping element is boron.
3. The amorphous carbon according to claim 1, wherein the doping element is nitrogen.
4. The amorphous carbon according to any one of claims 1 to 3, wherein a concentration of the doping element is 10 atomic percent or lower.
5. The amorphous carbon according to any one of claims 1 to 4, wherein the concentration of the hydrogen is in a range of 17 atomic percent to 27 atomic percent.
6. A method of manufacturing amorphous carbon, characterized by comprising: producing plasma of a raw material gas in a chamber; and forming amorphous carbon on a substrate placed in the chamber using the plasma, wherein a distance from a generation portion, on which the plasma is generated, to the • substrate is set to be in a range of 0.5 cm to 10 cm, and a temperature of the substrate is set to be in a range of 250 0C to 500 °C.
7. A solar cell characterized by comprising the amorphous carbon according to any one of claims 1 to 5.
PCT/IB2010/000062 2009-01-16 2010-01-15 Amorphous carbon, method of manufacturing the same, and solar cell including the same WO2010082120A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2009-007639 2009-01-16
JP2009007639A JP2010165908A (en) 2009-01-16 2009-01-16 Amorphous carbon and method of manufacturing the same

Publications (1)

Publication Number Publication Date
WO2010082120A1 true WO2010082120A1 (en) 2010-07-22

Family

ID=42123162

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2010/000062 WO2010082120A1 (en) 2009-01-16 2010-01-15 Amorphous carbon, method of manufacturing the same, and solar cell including the same

Country Status (2)

Country Link
JP (1) JP2010165908A (en)
WO (1) WO2010082120A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012188688A (en) * 2011-03-09 2012-10-04 Yamaguchi Univ Forming method of diamond-like carbon thin film and electrode material formed with the thin film on metal base board
WO2013180179A1 (en) * 2012-06-01 2013-12-05 東京エレクトロン株式会社 Plasma etching method
JP6652770B2 (en) * 2016-04-04 2020-02-26 株式会社不二越 Method for producing separator for polymer electrolyte fuel cell

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003209270A (en) 2002-01-15 2003-07-25 Toyota Central Res & Dev Lab Inc Carbon photoelectric element and its manufacturing method

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003209270A (en) 2002-01-15 2003-07-25 Toyota Central Res & Dev Lab Inc Carbon photoelectric element and its manufacturing method

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
DORNER-REISEL A ET AL: "Characterisation of nitrogen modified diamond-like carbon films deposited by radio-frequency plasma enhanced chemical vapour deposition", DIAMOND AND RELATED MATERIALS, ELSEVIER SCIENCE PUBLISHERS, AMSTERDAM, NL LNKD- DOI:10.1016/J.DIAMOND.2004.12.014, vol. 14, no. 3-7, 1 March 2005 (2005-03-01), pages 1073 - 1077, XP025331506, ISSN: 0925-9635, [retrieved on 20050301] *
HE X -M ET AL: "Plasma-immersion ion-processed boron-doped diamond-like carbon films", JOURNAL OF PHYSICS: CONDENSED MATTER IOP PUBLISHING UK LNKD- DOI:10.1088/0953-8984/12/8/105, vol. 12, no. 8, 28 February 2000 (2000-02-28), pages L183 - L189, XP002581858, ISSN: 0953-8984 *
MA Z Q ET AL: "Boron-doped diamond-like amorphous carbon as photovoltaic films in solar cell", SOLAR ENERGY MATERIALS AND SOLAR CELLS, ELSEVIER SCIENCE PUBLISHERS, AMSTERDAM, NL LNKD- DOI:10.1016/S0927-0248(00)00400-1, vol. 69, no. 4, 1 November 2001 (2001-11-01), pages 339 - 344, XP004254741, ISSN: 0927-0248 *

Also Published As

Publication number Publication date
JP2010165908A (en) 2010-07-29

Similar Documents

Publication Publication Date Title
US7638413B2 (en) Method of fabricating semiconductor by nitrogen doping of silicon film
US20100178234A1 (en) Multilayer substrate and method for producing the same, diamond film and method for producing the same
JP2011162830A (en) Film-forming method with plasma cvd technique, substrate having film formed thereon, and film-forming apparatus
US7628856B2 (en) Method for producing substrate for single crystal diamond growth
CN110565066B (en) Co-doped diamond, preparation method thereof, semiconductor material and device
KR20130036298A (en) Plasma-enhanced chemical vapor deposition of crystalline germanium
CN103422164A (en) Method for controlling N-type 4H-SiC homogenous epitaxial doping
JP2014187113A (en) Vapor deposition apparatus and vapor deposition method
JP3769642B2 (en) N-type semiconductor diamond and method for producing the same
WO2010082120A1 (en) Amorphous carbon, method of manufacturing the same, and solar cell including the same
JP2006216921A (en) Process for fabricating photoelectric converter and photoelectric converter
JP2010116287A (en) Amorphous carbon semiconductor and production method of the same
JP5053595B2 (en) DLC film forming method and DLC film manufacturing apparatus
WO2004061167A1 (en) LOW-RESISTANCE n TYPE SEMICONDUCTOR DIAMOND AND PROCESS FOR PRODUCING THE SAME
JP5502210B2 (en) Microcrystalline semiconductor thin film manufacturing method
JP7400389B2 (en) Silicon carbide polycrystalline film, silicon carbide polycrystalline film manufacturing method, and silicon carbide polycrystalline film forming apparatus
CN104810248A (en) Original position processing method applicable to 4-degree and 8-degree off-axis silicon surface silicon carbide substrates
JP5120924B2 (en) Method for producing amorphous carbon film
CN112136203B (en) Method for manufacturing SiC epitaxial substrate
KR101402741B1 (en) Method of forming quantum dots
CN104233465A (en) Preparation method for controlling epitaxial growth of heavily doped pressure N-type silicon carbide film
JP2012049472A (en) Amorphous carbon and method of manufacturing the same
KR20130093490A (en) A method and apparatus for depositing a microcrystalline material in photovoltaic application
Hassan et al. Comparative study on chemical vapor deposition of diamond-like carbon films from methane and acetylene using RF plasma
JP2012038916A (en) Amorphous carbon film and solar cell

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: 10703502

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 10703502

Country of ref document: EP

Kind code of ref document: A1