WO2013031923A1 - Procédé permettant de produire un lingot de semi-conducteur - Google Patents

Procédé permettant de produire un lingot de semi-conducteur Download PDF

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Publication number
WO2013031923A1
WO2013031923A1 PCT/JP2012/072067 JP2012072067W WO2013031923A1 WO 2013031923 A1 WO2013031923 A1 WO 2013031923A1 JP 2012072067 W JP2012072067 W JP 2012072067W WO 2013031923 A1 WO2013031923 A1 WO 2013031923A1
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Prior art keywords
seed crystal
mold
semiconductor
main surface
manufacturing
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PCT/JP2012/072067
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English (en)
Japanese (ja)
Inventor
跡部　淳一
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京セラ株式会社
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Priority to JP2013515445A priority Critical patent/JP5312713B1/ja
Publication of WO2013031923A1 publication Critical patent/WO2013031923A1/fr

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    • 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
    • H01L31/06—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 characterised by potential barriers
    • H01L31/068—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 characterised by potential barriers the potential barriers being only of the PN homojunction type, e.g. bulk silicon PN homojunction solar cells or thin film polycrystalline silicon PN homojunction solar cells
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
    • C30B11/003—Heating or cooling of the melt or the crystallised material
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
    • C30B11/14—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method characterised by the seed, e.g. its crystallographic orientation
    • C—CHEMISTRY; METALLURGY
    • C30—CRYSTAL GROWTH
    • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
    • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
    • C30B29/02—Elements
    • C30B29/06—Silicon
    • 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

Definitions

  • the present invention relates to a method for manufacturing a semiconductor ingot.
  • Solar cell elements are elements that convert light energy into electrical energy, and those using a silicon substrate as a semiconductor substrate for solar cell elements are widely used.
  • the silicon substrate is obtained by slicing a monocrystalline or polycrystalline silicon ingot to a predetermined thickness using a wire saw device or the like.
  • CZ Czochralski
  • FZ floating zone
  • a polycrystalline silicon ingot can be easily manufactured as compared with a single crystal silicon ingot.
  • the photoelectric conversion efficiency of a solar cell element using a polycrystalline silicon substrate as a semiconductor substrate is reduced due to crystal defects such as grain boundaries. This is generally inferior to a solar cell element using a single crystal silicon substrate.
  • the silicon melt when the silicon melt is injected into the mold, the silicon melt keeps in contact with a part of the seed crystal arranged on the bottom surface of the mold, so the seed crystal melts locally. It's easy to do.
  • the seed crystal melts to the bottom surface of the mold a part of the bottom surface of the silicon ingot starts crystal growth without starting from the seed crystal. For this reason, a silicon ingot with low crystal quality may be formed. This problem is particularly noticeable in the production of large ingots using a large amount of melt.
  • the heat removal from the melt is performed from the bottom surface and the inner peripheral surface of the mold, so the solid-liquid interface during crystal growth has a convex shape. Prone. Therefore, the crystal growth is in the direction from the outer periphery to the center of the ingot, so that the high-quality crystal region becomes smaller as the ingot grows, and crystal defects and impurity defects caused by the mold or the release material are reduced. It will increase.
  • one object of the present invention is to manufacture a high-quality and large-sized semiconductor ingot such as a silicon ingot, and using a substrate cut out from the semiconductor ingot, particularly a solar cell element excellent in characteristics such as photoelectric conversion efficiency It is an object of the present invention to provide a method for manufacturing a semiconductor ingot capable of obtaining the above.
  • a method for manufacturing a semiconductor ingot according to the present invention has a first main surface into which a semiconductor melt is poured and a second main surface located on the opposite side of the first main surface, and the second main surface.
  • the melt when the melt is injected into the mold, the melt continues to contact a part of the seed crystal disposed on the bottom surface of the mold so that the seed crystal is locally Even if it is melted, the seed crystal does not reach the bottom surface due to the presence of the protrusions, so that an ingot with few crystal defects is formed.
  • the contact area between the seed crystal and the bottom of the mold is narrower than that of the conventional seed crystal, the diffusion of impurities from the mold and the release material can be reduced.
  • FIG. 1 is a cross-sectional view schematically showing one embodiment of a method for manufacturing a semiconductor ingot according to the present invention.
  • Fig.2 (a) is a top view which shows typically an example of the seed crystal used for one Embodiment of the manufacturing method of the semiconductor ingot based on this invention
  • FIG.2 (b) is the side view.
  • Fig.3 (a) is a top view which shows typically an example of the seed crystal used for one Embodiment of the manufacturing method of the semiconductor ingot based on this invention
  • FIG.3 (b) is the side view.
  • FIG. 4A is a plan view schematically showing an example of a seed crystal used in one embodiment of a method for producing a semiconductor ingot according to the present invention, and FIG.
  • FIG. 4B is a side view thereof.
  • Fig.5 (a) is a top view which shows typically an example of the seed crystal used for one Embodiment of the manufacturing method of the semiconductor ingot based on this invention
  • FIG.5 (b) is the side view.
  • FIG. 6 is a cross-sectional view schematically showing an example of a manufacturing apparatus used in an embodiment of a method for manufacturing a semiconductor ingot according to the present invention.
  • FIG. 7 is a cross-sectional view schematically showing an example of a manufacturing apparatus used in an embodiment of a method for manufacturing a semiconductor ingot according to the present invention.
  • FIG. 8 is a cross-sectional view schematically showing an example of a manufacturing apparatus used in an embodiment of a method for manufacturing a semiconductor ingot according to the present invention.
  • FIG. 6 is a cross-sectional view schematically showing an example of a manufacturing apparatus used in an embodiment of a method for manufacturing a semiconductor ingot according to the present invention.
  • FIG. 7 is a cross-
  • FIG. 9 is a cross-sectional view schematically showing an example of a manufacturing apparatus used in an embodiment of a method for manufacturing a semiconductor ingot according to the present invention.
  • FIG. 10 is a diagram schematically showing an example of the solar cell element, and is a plan view seen from the light receiving surface side.
  • FIG. 11 is a diagram schematically showing an example of the solar cell element, and is a plan view seen from the non-light-receiving surface side.
  • FIG. 12 is a diagram schematically showing an example of the solar cell element, and is a cross-sectional view showing a state cut along the line KK in FIG.
  • a manufacturing apparatus for manufacturing a semiconductor ingot will be described.
  • a seed crystal 4 made of single crystal or polycrystalline silicon or germanium for manufacturing a semiconductor ingot is arranged in a mold 2, and a semiconductor made of the same material as the seed crystal 4 in an opening 2 a of the mold 2. It shows how the melt is poured.
  • the mold 2 has a cylindrical shape with a bottom as a whole, and is located, for example, between an opening 2a into which a semiconductor melt is poured from the crucible 1, a bottom surface 2b, and the opening 2a and the bottom surface 2b. And an inner peripheral side surface portion 2c.
  • the outer shape of the opening 2a is a square shape or a circular shape.
  • the semiconductor melt may be poured from an opening provided above the crucible 1 as shown in the figure.
  • a nozzle is provided on the lower surface of the crucible 1.
  • the semiconductor melt may be poured from the nozzle into the mold 2.
  • Both the crucible 1 and the mold 2 are not easily melted, deformed and decomposed at a temperature equal to or higher than the melting point of the semiconductor material such as silicon, and are less likely to react with the semiconductor material. It is made of a material in which impurities that reduce the characteristics of the solar cell element using the material are reduced as much as possible. For example, when producing a silicon ingot, both the crucible 1 and the mold 2 can use quartz or graphite.
  • a holder 5 that supports the mold 2 is disposed on the lower surface of the mold 2.
  • the holder 5 is made of, for example, quartz, graphite, or a carbon fiber reinforced carbon composite material, and has a function and a shape that removes heat from the bottom surface portion 2b while keeping it in close contact with the bottom surface portion 2b of the mold 2. ing.
  • the holder 5 is preferably supported by a cooling mechanism 6 as shown.
  • the cooling mechanism 6 is made of, for example, a metal such as stainless steel, and is a cooling plate or a water cooling jacket into which a cooling liquid such as water is introduced.
  • the seed crystal 4 has a first main surface 4a into which the semiconductor melt 3 is poured and a second main surface 4b located on the opposite side of the first main surface 4a. It is a plate-like body.
  • the seed crystal 4 has, for example, a square shape or a circular shape when viewed in plan, and each corner may be chamfered in an arc shape in the case of the square shape.
  • the seed crystal 4 has at least one protrusion 4c on the second main surface 4b side.
  • the protrusion 4c is disposed at least at the center of the second main surface 4b.
  • the projecting portion 4 c is further arranged, for example, in a ring shape at a portion along the peripheral edge of the second main surface 4 b, so that the seed crystal 4 can be stabilized in the mold 2.
  • the seed crystal 4 may be constituted by combining a plurality of small seed crystals.
  • the seed crystal 4 is a semiconductor crystal with few crystal defects such as impurities and crystal grain boundaries, and is preferably a single crystal, but may be a polycrystal. When using a polycrystal, it is preferable to use the one containing a single crystal region having a large grain size.
  • the size and shape of the projecting portion 4 c of the seed crystal 4 and the thickness of the plate-like body are set so as not to melt to the bottom when the semiconductor melt 3 is injected.
  • the protrusion 4c may be a columnar shape with a diameter of about 50 to 200 mm or a prismatic shape with a cross-sectional area of the same, the thickness is about 5 to 50 mm, and the thickness of the plate portion is about 5 to 50 mm. Preferably there is.
  • the seed crystal 4 may be integrated including the protruding portion 4c, or a plurality of small seed crystals may be combined.
  • a small seed crystal When a small seed crystal is combined, it can be easily applied to the mold 2 having various shapes, and the manufacturing costs of the seed crystal and the ingot can be reduced.
  • FIGS. 2 to 5 An example in which the seed crystal 4 is composed of a plurality of small seed crystals is shown in FIGS. 2 to 5, the region divided by the broken line 9 in the drawing is a small seed crystal.
  • the seed crystal 4 may be a small seed crystal that is equally divided into nine parts on a plane, and only the small seed crystal disposed in the lower center portion may be thickened.
  • the seed crystal 4 in order to stably dispose the seed crystal 4 in the mold 2, is also interposed between the small seed crystal located around the seed crystal 4 and the inner peripheral side surface of the mold 2 via the release material 8.
  • the crystal 4 is preferably fixed.
  • the seed crystal 4 is located under the center part of these small seed crystals, as shown in FIG. 5 (b).
  • the seed crystal 4 shown in FIG. 5 if the seed crystal 4 having a projecting portion along the peripheral edge on the second main surface 4 b side is prepared, the seed crystal 4 can be further stabilized in the mold 2. It can be arranged.
  • the seed crystal 4 can be reliably fixed to the mold 2 by drying the slurry-like release material 8 applied to the bottom surface portion 2b and the inner peripheral side surface portion 2c in the mold 2. At this time, only the projecting portion 4 c of the seed crystal 4 comes into contact with the bottom surface portion 2 b of the mold 2. Therefore, the diffusion of impurities contained in the mold 2 and the release material 8 into the semiconductor ingot is reduced, and a high-quality semiconductor ingot with few impurities can be manufactured.
  • a slurry-like release material is applied onto a pre-formed release material, and a seed crystal 4 is disposed thereon and dried.
  • the mold release property can be improved while fixing the seed crystal 4 in the mold 2.
  • the mold release material 8 applied in the mold 2 is originally used for the purpose of reducing the adhesion of the ingot to the mold 2 and the diffusion of impurities from the mold 2 to the semiconductor ingot, but when the semiconductor melt 3 is injected. In addition, it also has an effect of suppressing that the seed crystal 4 moves and normal seed casting is not performed.
  • the release material 8 is composed of a powder of silicon oxide, silicon nitride, silicon carbide, or the like, or a mixture thereof including a binder such as PVA (polyvinyl alcohol) and a solvent such as water or alcohol.
  • PVA polyvinyl alcohol
  • the resulting mixture is stirred to form a slurry, which is coated on the inner wall of the mold by means such as coating or spraying.
  • the mold release material 8 can be used repeatedly by suppressing the fusion of the inner wall of the mold 2 and the silicon ingot after the silicon melt is solidified. Moreover, since the joint part in the bottom face part and inner peripheral side face part of the mold 2 is reliably sealed by the applied release material 8, leakage of the silicon melt is reduced.
  • the peripheral edge 4d of the seed crystal 4 and the inner peripheral side face 2c of the mold 2 may be sealed with a release material 8 or the like, or a gap may be left.
  • the release material 8 or the like When sealed with the release material 8 or the like, the semiconductor melt 3 cannot reach the lower part of the seed crystal 4, so that the diffusion of impurities from the bottom surface 2 b of the mold 2 and the release material 8 to the semiconductor ingot.
  • the semiconductor melt 3 reaches the bottom surface portion 2b of the mold 2 and solidifies. Since a gap is formed between the seed crystal 4 and the seed crystal 4, the diffusion of impurities contained in the mold 2 and the release material 8 into the semiconductor ingot is reduced, and a high-quality semiconductor ingot with few impurities can be manufactured.
  • the semiconductor ingot is cooled from the center of the bottom surface. Furthermore, since the crystal growth direction is from the central part of the ingot to the peripheral part, crystal defects such as crystal grain boundaries and dislocations can be reduced.
  • the plate-like body 7 disposed between the projecting portion 4c of the seed crystal 4 and the bottom surface portion 2b of the mold 2 there is no melting, deformation, or decomposition at a temperature higher than the melting point of a semiconductor material such as silicon. It is possible to use ceramics or metal, etc., which are less likely to react with a semiconductor material such as silicon, and reduce impurities as much as possible to reduce the characteristics of the finished solar cell element in the semiconductor ingot. Silicon dioxide, silicon carbide Silicon nitride or the like is preferably used.
  • the basic manufacturing method will be described. First, it has the 1st main surface 4a into which a semiconductor melt is poured, and the 2nd main surface 4b located in the other side of the 1st main surface 4a, and the center part by the side of the 2nd main surface 4b protrudes.
  • a seed crystal preparation step for preparing the seed crystal 4 is performed.
  • a mold 2 having an opening 2a into which the semiconductor melt is poured, a bottom surface 2b, and an inner peripheral side surface 2c located between the opening 2a and the bottom 2b is prepared.
  • a mold preparation process is performed.
  • a seed crystal disposing step is performed in which the seed crystal 4 is disposed on the bottom surface 2b of the mold 2 with the second main surface 4a of the seed crystal 4 facing down.
  • an injection step of injecting the semiconductor melt 3 toward the central portion 4g of the first main surface 4a of the seed crystal 4 is performed.
  • the semiconductor melt 3 is injected from the crucible 1 into the mold 2 by tilting the crucible 1 containing the semiconductor melt into the mold 2 from the opening at the top of the crucible 1.
  • a liquid injection port may be provided at the bottom of the crucible 1 and the semiconductor melt 3 may be injected into the mold 2 from the liquid injection port.
  • the seed crystal preparation step it is preferable to prepare a seed crystal 4 in which a portion along the peripheral edge on the second main surface 4a side also protrudes.
  • a seed crystal 4 in which a plurality of small seed crystals are combined may be prepared.
  • the seed crystal 4 may be arranged on the bottom surface portion 2b of the mold 2 via the release material 8.
  • a plate-like body 7 having a thermal conductivity different from that of the seed crystal 4 is arranged on the bottom surface portion 2 b of the mold 2, and on the plate-like body 7.
  • a seed crystal 4 may be disposed.
  • the plate-shaped body 7 As the plate-shaped body 7, the 1st plate-shaped body 7a and several 2nd plate-shaped body with smaller heat conductivity than this 1st plate-shaped body 7a. 7b and before placing the seed crystal 4, the central portion of the bottom surface portion 2b of the mold 2 so that the first plate 7a is in contact with the central portion 4g of the second main surface 4b of the seed crystal 4
  • the plurality of second plate-like bodies 7b may be arranged around the first plate-like body 7a so as to come into contact with the peripheral edge of the seed crystal 4 on the second main surface 4b side.
  • the material of the first plate-like body 7a and the second plate-like body 7b may be the same or different from each other as long as the thermal conductivity is different.
  • two types of silicon dioxide plates 7a and 7b having different thermal conductivities may be used, or a combination of a first plate 7a made of silicon carbide and a second plate 7b made of silicon nitride. May be used.
  • the center portion of the bottom surface portion 2b of the mold 2 may be cooled so that the temperature is lower than the peripheral portion of the center portion.
  • the center part of the holder 5 or the cooling mechanism 6 may be cooled so that the temperature is lower than the peripheral part.
  • the outer surface portion corresponding to the center portion of the bottom surface portion 2b of the mold 2 is defined as the outer surface portion. It is good to cool so that temperature may become lower than the circumference
  • the cooling mechanism 6 is divided into a central portion 6 a and a peripheral edge portion 6 b, and a separate coolant whose temperature is controlled is supplied to each of the cooling mechanism 6 and the cooling mechanism 6. What is necessary is just to set the temperature of the cooling liquid supplied to the center part 6a of this to be lower than the temperature of the cooling liquid supplied to the peripheral part 6b of the cooling mechanism 6.
  • the holder 5 may be made of a material whose portion facing the outer surface portion of the mold 2 is made of a material having a higher thermal conductivity than the periphery of the portion. Specifically, for example, as shown in FIG. 9, the holder 5 is divided into a central portion 5a and a peripheral portion 5b, and the central portion 5a is made of carbon graphite, and the peripheral portion 5b is heated more than that. What is necessary is just to make it the holder 5 by producing with a carbon fiber reinforced carbon composite material with small conductivity, combining both, and integrating.
  • the semiconductor melt when the semiconductor melt is poured into the mold 2, the semiconductor melt continues to contact a part of the seed crystal 4 disposed on the bottom surface of the mold 2, Even if the seed crystal 4 is locally melted, the presence of the protrusion 4c prevents the seed crystal 4 from melting to the bottom surface, so that an ingot with few crystal defects is formed.
  • the contact area with the bottom surface of the mold 2 is narrower than that of the conventional seed crystal, the diffusion of impurities from the mold 2 and the release material 8 can be reduced. Thereby, since a high quality semiconductor ingot can be manufactured, the silicon ingot which can produce the solar cell element excellent in photoelectric conversion efficiency can be provided.
  • a semiconductor substrate can be cut out from the semiconductor ingot produced as described above and used as a semiconductor substrate of a solar cell element.
  • the solar cell element 30 includes a light receiving surface (upper surface in FIG. 12) 29a on which light is incident and a non-light receiving surface (lower surface in FIG. 12) that is the surface opposite to the light receiving surface 29a. 29b.
  • the solar cell element 30 includes a semiconductor substrate 21, and the semiconductor substrate 21 is provided on the first semiconductor layer 22, which is a semiconductor layer of one conductivity type, and on the light receiving surface 29 a side in the first semiconductor layer 22. And a second semiconductor layer 23 which is a semiconductor layer of a reverse conductivity type. An antireflection layer 24 is provided on the light receiving surface 29 a of the semiconductor substrate 21.
  • the solar cell element 30 includes a first electrode 25 provided on the light receiving surface 29 a of the semiconductor substrate 21 and a second electrode 26 provided on the non-light receiving surface 29 b of the semiconductor substrate 21.
  • the semiconductor substrate 21 including the first semiconductor layer 22 having one conductivity type (for example, p-type)
  • a silicon substrate is preferably used as the semiconductor substrate 21 including the first semiconductor layer 22 having one conductivity type (for example, p-type).
  • a p-type silicon substrate is prepared as a semiconductor substrate.
  • a polycrystalline silicon ingot produced by the method for producing an ingot according to the present invention is cut into a block having a desired shape, and then sliced using a multi-wire saw device or the like to form a substrate. be able to.
  • Boron (B) is preferably used as the p-type doping element, and the concentration is about 1 ⁇ 10 16 to 1 ⁇ 10 17 [atoms / cm 3 ]. At this time, the specific resistance value of the silicon substrate is 0.2. It is about 2 ⁇ ⁇ cm.
  • a method for doping boron into the silicon substrate an appropriate amount of boron element alone may be included at the time of manufacturing the silicon ingot, or an appropriate amount of boron-containing silicon lump whose doping concentration is already known may be included.
  • the thickness of the semiconductor substrate 21 is, for example, preferably 300 ⁇ m or less, and more preferably 200 ⁇ m or less.
  • the second semiconductor layer 23 that forms a pn junction with the first semiconductor layer 22 is a layer having a conductivity type opposite to that of the first semiconductor layer 22, and is provided on the light receiving surface 29 a side of the semiconductor substrate 21.
  • the second semiconductor layer 23 can be formed by diffusing impurities such as phosphorus (P) on the light receiving surface 29 a side of the semiconductor substrate 21.
  • the antireflection layer 24 plays a role of reducing the reflectance of light in a desired wavelength region and increasing the amount of photogenerated carriers.
  • the antireflection layer 24 is made of, for example, a silicon nitride film, a titanium oxide film, or a silicon oxide film.
  • the thickness of the antireflective layer 24 is appropriately selected depending on the constituent material, and is set so as to realize a nonreflective condition with respect to appropriate incident light.
  • the semiconductor substrate 21 made of silicon preferably has a refractive index of about 1.8 to 2.3 and a thickness of about 500 to 1200 mm.
  • a BSF (Back-Surface-Field) region 7 provided on the non-light-receiving surface 29b side of the semiconductor substrate 21 has a role of reducing a decrease in efficiency due to carrier recombination in the vicinity of the non-light-receiving surface 29b.
  • An internal electric field is formed on the light receiving surface 29b side.
  • the BSF region 27 has the same conductivity type as that of the first semiconductor layer 22, but has a majority carrier having a concentration higher than that of the majority carrier contained in the first semiconductor layer 22.
  • the BSF region 6 has a concentration of these dopant elements of 1 ⁇ 10 18 to 5 by diffusing a dopant element such as boron or aluminum on the non-light-receiving surface 29b side. It is preferably formed so as to be about ⁇ 10 21 atoms / cm 3 .
  • the first electrode 25 has a first output extraction electrode 25a and a plurality of linear first current collecting electrodes 25b. At least a part of the first output extraction electrode 25a intersects the first current collection electrode 25b.
  • the first output extraction electrode 25a has a width of about 1.3 to 2.5 mm, for example.
  • the first collector electrode 25b has a line width of about 50 to 200 ⁇ m and is thinner than the first output extraction electrode 25a.
  • a plurality of first current collecting electrodes 25b are provided with an interval of about 1.5 to 3 mm.
  • the thickness of the first electrode 25 is about 10 to 40 ⁇ m.
  • the first electrode 25 can be formed by applying a paste for forming an electrode made of, for example, silver powder, glass frit, an organic vehicle or the like into a desired shape by screen printing or the like, and then baking the paste.
  • the second electrode 26 has a second output extraction electrode 26a and a second current collecting electrode 26b.
  • the second output extraction electrode 26a has a thickness of about 10 to 30 ⁇ m and a width of about 1.3 to 7 mm.
  • the second output extraction electrode 26a can be formed of the same material and manufacturing method as the first electrode 25 described above. For example, you may form by apply
  • the second collector electrode 26b has a thickness of about 15 to 50 ⁇ m, and is formed on substantially the entire surface of the non-light-receiving surface 29b of the semiconductor substrate 21 excluding a part of the second output extraction electrode 26a.
  • the second current collecting electrode 26b can be formed, for example, by applying an aluminum paste in a desired shape and baking it.
  • a silicon ingot was produced using a seed crystal and a mold for producing a semiconductor ingot shown in FIGS.
  • a quartz crucible 1 shown in FIG. 1 a graphite mold 2 and a seed crystal 4 composed of five small seed crystals as shown in FIG. 2 were prepared.
  • Example 1 as the seed crystal 4, five pieces of single crystal silicon having a Miller index having a (100) plane crystal orientation and a 150 mm square and a height of 10 mm were used.
  • the seed crystal 4 used was a seed crystal 4 of Example 1 provided with a small seed crystal of 20 mm ⁇ 150 mm and a height of 10 mm at the periphery.
  • Example 3 in the case of Example 2, a carbon fiber having a thermal conductivity of 100 W / m ⁇ K or more at the center portion of the holder and a thermal conductivity smaller than this at the holder peripheral portion. Reinforced carbon composite was used.
  • the cooling mechanism 6 is divided into the central portion 6a and the peripheral portion 6b, and the cooling water is allowed to flow through two systems of the central portion and the peripheral portion.
  • the ingot was manufactured by setting the set temperature of the cooling water supplied to the central portion 6a to 15 ° C and the set temperature of the cooling water supplied to the peripheral portion 6b to 20 ° C.
  • a powder made of silicon nitride having an average particle size of about 0.5 ⁇ m, a powder made of silicon oxide having an average particle size of about 20 ⁇ m, and a PVA aqueous solution as a binder solution are mixed on the inner peripheral side surface portion 2 c of the mold 2.
  • the release material 8 in the form of a slurry was applied so that the coating weight per unit area was about 0.1 g / cm 2 .
  • the projecting portion 4 c of the seed crystal 4 was fixed in the mold 2 via a release material 8. Further, a location located in the vicinity of the inner peripheral side surface portion 2 c of the small-crystal crystal mold 2 was also fixed through the release material 8.
  • a large number of silicon chunks of a total amount of 100 kg are put into the crucible 1, and the silicon in the crucible 1 is heated and melted by heating means (not shown) arranged around the crucible 1 to obtain a silicon melt 3 of about 1420 ° C.
  • Heating means not shown
  • a silicon melt 3 of about 1420 ° C. was injected toward the central portion 4 g of the seed crystal 4 to produce a silicon ingot in the mold 2.
  • a silicon ingot was produced under the same conditions as in the example using a seed crystal having no protrusion.
  • the seed crystal 4 melts until reaching the bottom surface part 2b of the mold 2, and a fine polycrystal grows from the central part of the silicon ingot. This was observed by visual observation of the cross section of the ingot and by observation of etch pits using a mixed acid composed of a mixture of hydrofluoric acid, nitric acid and acetic acid.
  • a silicon substrate was sliced from the center of the obtained silicon ingot, and then a solar cell element using this as a semiconductor substrate was produced as follows (refer to FIGS. 10 to 12 for the solar cell element). .
  • the polycrystalline silicon ingot produced in this example was sliced into a polycrystalline silicon substrate (semiconductor substrate 21) having a thickness of 200 ⁇ m, an outer shape of 150 mm ⁇ 150 mm, and a specific resistance of 1 to 1.2 ⁇ ⁇ cm.
  • the damaged layer on the surface was cleaned by etching with a NaOH solution.
  • the second semiconductor layer 23 was formed by a vapor phase thermal diffusion method using POCl 3 as a diffusion source. At this time, the sheet resistance of the second semiconductor layer 23 was 70 ⁇ / ⁇ . Further, after removing the phosphor glass by etching with a hydrofluoric acid solution and performing pn separation using a laser beam, a silicon nitride film to be the antireflection layer 24 was formed on the light receiving surface 29a by PECVD.
  • the BSF region 27 and the second current collecting electrode 26b were formed by applying and baking an aluminum paste on substantially the entire surface of the non-light-receiving surface 29b of the semiconductor substrate 21.
  • a silver paste was applied and fired on the light receiving surface 29a and the non-light receiving surface 29b to form the first electrode 25 and the second output extraction electrode 26a to obtain the solar cell element 30.
  • the solar cell using the semiconductor substrate of the comparative example was measured.
  • the battery element was 16.2%
  • the solar cell element using the semiconductor substrate of Example 1 was 16.8%
  • the solar cell element using the semiconductor substrate of Example 2 was 16.5%.
  • %, 16.6% for the solar cell element using the semiconductor substrate of Example 3 was 16.7% for the solar cell element using the semiconductor substrate of Example 4. From these results, it was also confirmed that the characteristics could be improved as the solar cell element using a semiconductor substrate with good crystallinity.
  • crucible 2 mold 2a: opening 2b: bottom surface 2c: inner peripheral side surface 3: semiconductor melt 4: seed crystal 4a: first main surface 4b: second main surface 4c: protrusion 5: holder 6: Cooling mechanism 7: plate-like body 7a: first plate-like body 7b: second plate-like body 8: release material 21: semiconductor substrate (silicon substrate) 22: 1st semiconductor layer 23: 2nd semiconductor layer 24: Antireflection layer 25: 1st electrode 25a: 1st output extraction electrode 25b: 1st current collection electrode 25c: Auxiliary electrode 26: 2nd electrode 6a: 2nd output Extraction electrode 6b: second current collecting electrode 27: BSF region 29a: light receiving surface 29b: non-light receiving surface 30: solar cell element

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Abstract

La présente invention se rapporte à un procédé permettant de produire un lingot de semi-conducteur, ledit procédé comprenant : une étape de préparation d'un germe cristallin destinée à préparer un germe cristallin qui comprend une première surface principale sur laquelle est versé un métal liquide semi-conducteur, ainsi qu'une seconde surface principale qui se trouve sur le côté opposé à la première surface principale, la partie centrale faisant saillie vers la seconde surface principale ; une étape de préparation de moule destinée à préparer un moule qui présente une ouverture à travers laquelle le métal liquide semi-conducteur est versé, une surface inférieure et une surface latérale interne qui est positionnée entre l'ouverture et la surface inférieure ; une étape d'agencement de germe cristallin destinée à agencer le germe cristallin sur la surface inférieure du moule, la seconde surface principale se trouvant en bas ; une étape de versage destinée à verser le métal liquide semi-conducteur vers la partie centrale de la première surface principale du germe cristallin ; et une étape de solidification destinée à solidifier le métal liquide semi-cristallin dans le moule.
PCT/JP2012/072067 2011-08-30 2012-08-30 Procédé permettant de produire un lingot de semi-conducteur WO2013031923A1 (fr)

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CN104726933A (zh) * 2013-12-20 2015-06-24 昆山中辰矽晶有限公司 用于晶碇铸造炉的冷却装置及铸造晶碇的方法
JP2015163575A (ja) * 2014-01-29 2015-09-10 京セラ株式会社 鋳造用装置およびインゴットの製造方法
JP2015189589A (ja) * 2014-03-27 2015-11-02 京セラ株式会社 インゴット製造装置およびシリコンインゴットの製造方法
JP2015189588A (ja) * 2014-03-27 2015-11-02 京セラ株式会社 インゴット製造装置およびシリコンインゴットの製造方法
JP2015214473A (ja) * 2014-04-24 2015-12-03 京セラ株式会社 多結晶シリコンのインゴットの製造方法
WO2021010468A1 (fr) * 2019-07-18 2021-01-21 京セラ株式会社 Lingot de silicium, bloc de silicium, substrat de silicium, procédé de production de lingot de silicium et cellule solaire
CN112941628A (zh) * 2019-12-11 2021-06-11 苏州阿特斯阳光电力科技有限公司 晶体硅锭的制备方法
CN113564695A (zh) * 2020-04-29 2021-10-29 江西赛维Ldk太阳能高科技有限公司 用于铸造单晶硅的籽晶铺设方法、单晶硅锭及其铸造方法

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JPH11116386A (ja) * 1997-10-13 1999-04-27 Mitsubishi Materials Corp 一方向凝固多結晶組織を有するシリコンインゴットの製造方法
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Publication number Priority date Publication date Assignee Title
CN104726933A (zh) * 2013-12-20 2015-06-24 昆山中辰矽晶有限公司 用于晶碇铸造炉的冷却装置及铸造晶碇的方法
JP2015163575A (ja) * 2014-01-29 2015-09-10 京セラ株式会社 鋳造用装置およびインゴットの製造方法
JP2015189589A (ja) * 2014-03-27 2015-11-02 京セラ株式会社 インゴット製造装置およびシリコンインゴットの製造方法
JP2015189588A (ja) * 2014-03-27 2015-11-02 京セラ株式会社 インゴット製造装置およびシリコンインゴットの製造方法
JP2015214473A (ja) * 2014-04-24 2015-12-03 京セラ株式会社 多結晶シリコンのインゴットの製造方法
WO2021010468A1 (fr) * 2019-07-18 2021-01-21 京セラ株式会社 Lingot de silicium, bloc de silicium, substrat de silicium, procédé de production de lingot de silicium et cellule solaire
JPWO2021010468A1 (fr) * 2019-07-18 2021-01-21
JP7201815B2 (ja) 2019-07-18 2023-01-10 京セラ株式会社 シリコンのインゴット、シリコンのブロック、シリコンの基板、シリコンのインゴットの製造方法および太陽電池
CN112941628A (zh) * 2019-12-11 2021-06-11 苏州阿特斯阳光电力科技有限公司 晶体硅锭的制备方法
CN113564695A (zh) * 2020-04-29 2021-10-29 江西赛维Ldk太阳能高科技有限公司 用于铸造单晶硅的籽晶铺设方法、单晶硅锭及其铸造方法
CN113564695B (zh) * 2020-04-29 2023-05-05 江西赛维Ldk太阳能高科技有限公司 用于铸造单晶硅的籽晶铺设方法、单晶硅锭及其铸造方法

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