WO2023079957A1 - Composition à diffusion d'impuretés de type p et procédé de production d'une cellule solaire l'utilisant - Google Patents

Composition à diffusion d'impuretés de type p et procédé de production d'une cellule solaire l'utilisant Download PDF

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WO2023079957A1
WO2023079957A1 PCT/JP2022/038911 JP2022038911W WO2023079957A1 WO 2023079957 A1 WO2023079957 A1 WO 2023079957A1 JP 2022038911 W JP2022038911 W JP 2022038911W WO 2023079957 A1 WO2023079957 A1 WO 2023079957A1
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impurity diffusion
type impurity
diffusion composition
group
film
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PCT/JP2022/038911
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English (en)
Japanese (ja)
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田邉脩平
北田剛
弓場智之
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東レ株式会社
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Priority to CN202280070587.6A priority Critical patent/CN118202443A/zh
Publication of WO2023079957A1 publication Critical patent/WO2023079957A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/22—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities
    • H01L21/225—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities using diffusion into or out of a solid from or into a solid phase, e.g. a doped oxide layer
    • 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
    • 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 present invention relates to a p-type impurity diffusion composition and a method for manufacturing a solar cell using the same.
  • a method of forming a diffusion source on the substrate and diffusing the impurity into the semiconductor substrate by thermal diffusion is used. being taken.
  • the diffusion source is formed by a CVD method or a solution coating method of a liquid impurity diffusion composition.
  • a thermal oxide film is first formed on the surface of a semiconductor substrate, and then a resist having a predetermined pattern is laminated on the thermal oxide film by photolithography.
  • n-type or p-type diffusion composition is applied to adhere the diffusion composition to the openings of the mask.
  • the impurity component in the composition is thermally diffused into the semiconductor substrate at 600 to 1250° C. to form an n-type or p-type impurity diffusion layer.
  • the present invention has been made based on the circumstances as described above, and an object of the present invention is to provide a p-type impurity diffusion composition that achieves thinning of the pattern.
  • the p-type impurity diffusion composition of the present invention has the following constitution.
  • a p-type impurity diffusion composition containing (A) a Group 13 element compound, (B) a hydroxyl group-containing polymer, and (C) an organic filler comprising a crosslinked polymer.
  • the (C) organic filler made of a crosslinked polymer has an oxyethylene group or an oxypropylene group.
  • the (C) organic filler made of a crosslinked polymer, (C-1) a compound having at least one selected from an acryloyl group and a methacryloyl group and (C-2) a compound having an acryloyl group or a methacryloyl group attached to both ends of a structure having an oxyethylene group or an oxypropylene group.
  • the p-type impurity diffusion composition according to any one of [1] to [3], wherein (B) the hydroxyl group-containing polymer is polyvinyl alcohol.
  • a method for manufacturing a solar cell including a step of forming an impurity diffusion layer with two or more levels of different impurity concentrations, At least one level or more of impurity diffusion layer is formed by applying the p-type impurity diffusion composition according to any one of [1] to [6] to a semiconductor substrate to partially form an impurity diffusion composition film (a).
  • the method for producing a solar cell according to [8], wherein the step of diffusing impurities in the portion where the impurity diffusion composition film (a) is not formed is a step of heating in an atmosphere containing an impurity diffusion component.
  • the p-type impurity diffusion composition of the present invention contains (A) a Group 13 element compound, (B) a hydroxyl group-containing polymer, and (C) an organic filler consisting of a crosslinked polymer.
  • the p-type impurity diffusion composition of the present invention can form a p-type impurity diffusion layer in a semiconductor substrate by containing a group 13 element compound as an impurity diffusion component.
  • a boron compound is preferable as the Group 13 element compound.
  • boron compounds include boric acid, diboron trioxide, methylboronic acid, phenylboronic acid, trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, trioctyl borate, and triphenyl borate.
  • boric acid and diboron trioxide are preferable from the viewpoint of doping properties.
  • the content of (A) the group 13 element compound contained in the p-type impurity diffusion composition can be arbitrarily determined depending on the resistance value required for the semiconductor substrate, but it is 0.1 in 100% by mass of the entire composition. It is preferably up to 10% by mass, more preferably 0.5 to 5% by mass.
  • (B) hydroxyl group-containing polymer In the p-type impurity diffusion composition of the present invention, (B) the hydroxyl group-containing polymer forms a complex with (A) the group 13 element compound, particularly preferably the boron compound, to form a uniform coating during coating. is an ingredient.
  • the (B) hydroxyl group-containing polymer examples include polyvinyl alcohol resins such as polyvinyl alcohol and modified polyvinyl alcohol; vinyl alcohol derivatives such as polyvinyl acetal and polyvinyl butyral; polyalkylene oxides such as polyethylene oxide and polypropylene oxide; Polyhydroxyacrylates such as ethyl cellulose, polyhydroxymethyl acrylate, polyhydroxyethyl acrylate, polyhydroxypropyl acrylate may be mentioned.
  • polyvinyl alcohol is preferable from the viewpoint of the ability to form a complex with (A) a group 13 element compound, particularly preferably a boron compound, the stability of the formed complex, and the storage stability of the p-type impurity diffusion composition.
  • the degree of saponification of polyvinyl alcohol is preferably 20 mol% or more and less than 70 mol%.
  • the degree of saponification is preferably 20 mol% or more and less than 70 mol%.
  • the degree of saponification of polyvinyl alcohol is more preferably 30 mol % or more and less than 50 mol %.
  • the average degree of polymerization of polyvinyl alcohol is most preferably 150 to 1000 in terms of solubility and complex stability.
  • both the average degree of polymerization and the degree of saponification are values measured according to JIS K 6726 (1994).
  • the degree of saponification is a value measured by the back titration method among the methods described in the JIS.
  • the content of (B) the hydroxyl group-containing polymer is preferably 1 to 20% by mass based on 100% by mass of the entire composition. Preferably, it is 5 to 15% by mass.
  • the mass ratio (A):(B) of (A) the Group 13 element compound and (B) the hydroxyl group-containing polymer is preferably 1:20 to 1:1, and 1: 15 to 1:3 is more preferred.
  • the p-type impurity diffusion composition of the present invention contains (C) an organic filler comprising a crosslinked polymer in order to impart thixotropic properties and improve printing characteristics.
  • thixotropy means increasing the ratio ( ⁇ 1 / ⁇ 2 ) of the viscosity ( ⁇ 1 ) at low shear stress and the viscosity ( ⁇ 2 ) at high shear stress. By increasing the thixotropy, it is possible to improve the pattern accuracy of screen printing. This is for the following reasons.
  • the p-type impurity diffusion composition with high thixotropy has low viscosity at high shear stress, clogging of the screen hardly occurs during screen printing, and high viscosity at low shear stress causes bleeding immediately after printing and reduction of pattern line width. It becomes difficult to get fat.
  • the thixotropy can be determined from the ratio of viscosities at different rotational speeds obtained by the viscosity measurement method described above.
  • the thixotropy is defined as the ratio ( ⁇ 2 / ⁇ 20 ) of the viscosity ( ⁇ 20 ) at a rotation speed of 20 rpm and the viscosity ( ⁇ 2 ) at a rotation speed of 2 rpm.
  • the thixotropy is preferably 2 or more, more preferably 3 or more.
  • the (C) organic filler composed of a crosslinked polymer stabilizes the complex of (A) the group 13 element compound and (B) the hydroxyl group-containing polymer, and improves the dispersibility in these complexes. This contributes to the thinning of the pattern, improves the uniformity of the resistance value after diffusion, reduces the resistance value, and has the effect of improving the carrier life.
  • crosslinked polymers include, but are not limited to, polymers of acryloyl compounds, methacryloyl compounds, vinyl compounds, epoxy compounds, and phenol compounds.
  • the organic filler composed of a crosslinked polymer contains oxyethylene groups. Alternatively, it preferably has an oxypropylene group.
  • the oxyethylene group or oxypropylene group may be contained in the network of the network structure of the crosslinked polymer, or may be contained at the end of the network structure.
  • the organic filler composed of a crosslinked polymer is more preferably (C-1) a compound having at least one selected from acryloyl groups and methacryloyl groups and (C-2) an oxyethylene group or an oxypropylene group. It is a crosslinked product obtained by copolymerizing a compound in which an acryloyl group or a methacryloyl group is bonded to both ends of the structure having the structure. Thereby, in addition to the oxyethylene group or oxypropylene group of (C-2), the carbonyl group in the acryloyl group or methacryloyl group of (C-1) is combined with (A) a Group 13 element compound and (B) a hydroxyl group. It contributes to further stabilization of the complex with the contained polymer. As a result, a finer pattern, a lower resistance value, an improved uniformity of the resistance value, and a further improvement in the carrier life can be expected.
  • (C-1) Specific examples of the compound having at least one selected from an acryloyl group and a methacryloyl group include acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, methacrylic acid- Examples include, but are not limited to, 2-hydroxyethyl, glycidyl acrylate, glycidyl methacrylate, and the like.
  • Specific examples of compounds in which acrylic groups or methacrylic groups are bonded to both ends of a structure having an oxyethylene group or oxypropylene group include polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, ethylene glycol diacrylate, and ethylene. Examples include, but are not limited to, glycol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, dipropylene glycol diacrylate, dipropylene glycol dimethacrylate, polypropylene glycol diacrylate, polypropylene glycol dimethacrylate, and the like.
  • (C-2) is 0.5 to 20 mol per 100 mol% of (C-1). %, more preferably 1 to 10 mol %.
  • (C) an organic filler composed of a crosslinked polymer can be obtained.
  • it can be obtained by suspension polymerization at 60 to 100° C. in a poor solvent and isolating the resulting fine particles, but is not limited to these methods.
  • the p-type impurity diffusion composition of the present invention preferably contains 100 to 1000% by mass of (C) an organic filler composed of a crosslinked polymer when (B) the hydroxyl group-containing polymer is 100% by mass. It is preferably 200 to 700% by mass.
  • the p-type impurity diffusion composition of the present invention preferably further contains a solvent.
  • the solvent refers to a solvent that is liquid at normal pressure and 23° C. and capable of dissolving (B) the hydroxyl group-containing polymer and dispersing (C) the organic filler composed of the crosslinked polymer.
  • the solvent content is preferably 10 to 90% by mass, more preferably 20 to 70% by mass, based on 100% by mass of the entire composition.
  • the solvent can be used without any particular limitation, but from the viewpoint of further improving the printability when using a screen printing method, a spin coat printing method, or the like, a solvent with a boiling point of 100°C or higher is preferable. If the boiling point is 100° C. or higher, for example, when the p-type impurity diffusion composition is printed on a printing plate used in screen printing, the p-type impurity diffusion composition is prevented from drying and sticking on the printing plate. can. It is preferably 160° C. or higher, more preferably 180° C. or higher.
  • the content of the solvent with a boiling point of 100°C or higher is preferably 20% by weight or more with respect to the total amount of the solvent.
  • solvents having a boiling point of 100°C or higher include ethyl lactate (boiling point 155°C), diacetone alcohol (boiling point 169°C), propylene glycol monomethyl ether acetate (boiling point 145°C), propylene glycol monomethyl ether (boiling point 120°C), and 3-methoxy.
  • the solvent more preferably contains 1,3-propanediol. Containing 1,3-propanediol further improves the stability of the complex of (A) the Group 13 element compound and (B) the hydroxyl group-containing polymer.
  • the phenomenon in which (A) the group 13 element compound and (B) the hydroxyl group-containing polymer that have already formed a complex further react to form a three-dimensional complex is easily suppressed, and the p-type impurity diffusion composition It becomes easy to suppress the increase in the viscosity of the substance over time and the generation of gel-like foreign matter due to the increase in viscosity.
  • the uniformity of the resistance value is not impaired and it can be used stably. .
  • the p-type impurity diffusion composition of the present invention does not impair the thinning of the pattern from the viewpoint of improving printability and is within a range that is not affected by the residual inorganic component (C)
  • the organic filler made of a crosslinked polymer may contain a thixotropic agent.
  • Fine particles of silicon oxide are preferred from the viewpoint of compatibility with other components in the composition and reduction of residue.
  • the viscosity of the p-type impurity diffusion composition of the present invention is not limited, and can be appropriately changed according to the printing method and film thickness.
  • the viscosity of the diffusion composition is preferably 5,000 mPa ⁇ s or more. This is because it is possible to suppress bleeding of the printed pattern and obtain a good pattern.
  • a more preferable viscosity is 10,000 mPa ⁇ s or more. Although there is no particular upper limit, it is preferably 100,000 mPa ⁇ s or less from the viewpoint of storage stability and handleability.
  • the viscosity is less than 1,000 mPa s, it is a value measured at a rotation speed of 20 rpm using an E-type digital viscometer based on JIS Z 8803 (1991) "Solution viscosity-measurement method", In the case of 1,000 mPa ⁇ s or more, it is a value measured at a rotational speed of 20 rpm using a B-type digital viscometer based on JIS Z 8803 (1991) "Solution viscosity-measurement method".
  • the p-type impurity diffusion composition of the present invention may contain a surfactant. By containing a surfactant, coating unevenness is improved, and a more uniform coating film can be obtained.
  • a surfactant fluorine-based surfactants and silicone-based surfactants are preferably used.
  • the content of the surfactant, if included, is preferably 0.0001 to 1% by weight in the p-type impurity diffusion composition.
  • the solid content concentration of the p-type impurity diffusion composition of the present invention is not particularly limited, but is preferably in the range of 1% by mass or more and 90% by mass or less. If the concentration is lower than this range, the coating film thickness becomes too thin, and it may be difficult to obtain the desired doping properties and masking properties. Moreover, if the concentration is higher than this range, the storage stability may be lowered.
  • the p-type impurity diffusion composition of the present invention is used in photovoltaic elements such as solar cells, and semiconductor devices in which impurity diffusion regions are patterned on the semiconductor surface, such as transistor arrays, diode arrays, photodiode arrays, and transducers. can also be expanded.
  • a solar cell manufacturing method of the present invention includes a step of forming an impurity diffusion layer with two or more levels of different impurity concentrations, Formation of at least one or more levels of impurity diffusion layer is a step of applying the p-type impurity diffusion composition of the present invention to a semiconductor substrate to partially form an impurity diffusion composition film (a); heating the obtained impurity-diffused composition film (a) to diffuse impurities into the semiconductor substrate to form an impurity-diffused layer (b).
  • different impurity concentrations means that the difference in impurity concentration is 1 ⁇ 10 17 atoms/cm 3 or more, and the difference in sheet resistance of the portion of the substrate surface where the impurity diffusion layer is formed is 10 ⁇ / ⁇ or more. Point. The present embodiment will be described in detail below.
  • a semiconductor substrate 1 is partially coated with the p-type impurity diffusion composition of the present invention to form a pattern 2 of the p-type impurity diffusion composition film (a). .
  • semiconductor substrates include n-type single-crystal silicon, polycrystalline silicon, and crystalline silicon substrates mixed with other elements such as germanium and carbon, each having an impurity concentration of 10 15 to 10 16 atoms/cm 3 . mentioned. It is also possible to use p-type single crystal silicon or a semiconductor other than silicon.
  • the semiconductor substrate has a thickness of 50 to 300 ⁇ m and an outline of a substantially square shape with a side of 100 to 250 mm.
  • the surface of the semiconductor substrate is formed with a large number of uneven texture shapes having a typical width of about 40 to 100 ⁇ m and a depth of about 3 to 4 ⁇ m.
  • the step of forming impurity diffusion layers with different impurity concentrations of two or more levels at least one level or more of impurity diffusion layers are formed by applying the p-type impurity diffusion composition of the present invention to a semiconductor substrate and partially removing p-type impurities. It includes a step of forming a diffusion composition film (a) and a step of heating it to diffuse impurities into a semiconductor substrate to form an impurity diffusion layer (b).
  • Examples of methods for applying the p-type impurity diffusion composition include spin coating, screen printing, inkjet printing, slit coating, spray coating, letterpress printing, and intaglio printing.
  • the semiconductor substrate 1 coated with the p-type impurity diffusion composition is dried with a hot plate, an oven, or the like at a temperature in the range of 50 to 300° C. for 30 seconds to 30 minutes. to form a pattern 2 of the p-type impurity diffusion composition film (a).
  • the thickness of the p-type impurity diffusion composition film (a) after drying is preferably 100 nm or more from the viewpoint of impurity diffusion, and preferably 7 ⁇ m or less from the viewpoint of residue after etching.
  • the impurity diffusion composition film (a) is heated and diffused into the semiconductor substrate 1 to form an impurity diffusion layer (b).
  • a known thermal diffusion method can be used, and for example, methods such as electric heating, infrared heating, laser heating, and microwave heating can be used.
  • the time and temperature of thermal diffusion can be appropriately set so as to obtain desired diffusion characteristics such as impurity concentration and diffusion depth.
  • a diffusion layer having a surface impurity concentration of 10 19 to 10 21 atoms/cm 3 can be formed by thermally diffusing at 800° C. or higher and 1200° C. or lower for 1 to 120 minutes.
  • the diffusion atmosphere is not particularly limited, and may be carried out in the air, or an inert gas such as nitrogen or argon may be used to appropriately control the amount of oxygen in the atmosphere. From the viewpoint of shortening the diffusion time, it is preferable to set the oxygen concentration in the atmosphere to 3% or less. If necessary, the p-type impurity diffusion composition film (a) may be baked at a temperature of 200° C. to 850° C. before diffusion to decompose and remove organic matter.
  • an impurity diffusion composition film (a) is formed using the impurity diffusion composition film (a) as a mask. It is preferable to include a step of diffusing impurities into the unformed portion. Specifically, as shown in FIG. 1(iii), the pattern 2 of the impurity diffusion composition film (a) is used as a mask, and the non-patterned portion has the same conductivity as the impurity diffusion layer (b), and An impurity diffusion layer (c) having a different impurity concentration is formed.
  • the step of diffusing impurities into a portion where the impurity diffusion composition film (a) is not formed using the impurity diffusion composition film (a) as a mask includes: is heated to diffuse impurities into the semiconductor substrate 1 to form an impurity diffusion layer (b).
  • ions containing impurity diffusion components are implanted into the semiconductor substrate 1 with the pattern 2 of the impurity diffusion composition film (a) and then annealed.
  • a method of heating the semiconductor substrate 1 with the pattern 2 of the impurity diffusion composition film (a) in an atmosphere containing an impurity diffusion component Another impurity diffusion composition having a different impurity concentration and having a different impurity concentration is applied to the portion where the impurity diffusion composition film (a) is not formed to form an impurity diffusion composition film, followed by electric heating, infrared heating, laser A method of heating, microwave heating, and the like can be mentioned.
  • the step of diffusing the impurity into the portion where the impurity diffusion composition film (a) is not formed is preferably the step of heating in an atmosphere containing the impurity diffusion component.
  • the impurity diffusion layer (c) can be formed by heating the semiconductor substrate 1 with the pattern 2 of the impurity diffusion composition film (a) at 800 to 1000° C. in an atmosphere containing an impurity diffusion component.
  • the impurity concentration of the impurity diffusion layer (c) can be set higher or lower than the impurity concentration of the impurity diffusion layer (b) by adjusting the gas pressure and heating conditions.
  • the substrate is put into the heating furnace of FIG. They may be formed at the same time.
  • an impurity diffusion layer (c) having an impurity concentration different from that of the impurity diffusion layer (b) is formed in one batch by additionally introducing a gas containing the component and heating under conditions different from the heating conditions for only the inert gas.
  • oxidation of the surface of the semiconductor substrate in the portion where the impurity diffusion composition film (a) is not formed causes boron silicate glass when the impurity is p-type, and phosphor silicate glass when the impurity is n-type.
  • a layer (d) comprising silicon oxide, such as glass, is formed.
  • the pattern 2 of the impurity diffusion composition film (a) and the layer (d) containing silicon oxide can be removed by a known etching method.
  • the material used for etching is not particularly limited, but includes, for example, at least one of hydrogen fluoride, ammonium, phosphoric acid, sulfuric acid, and nitric acid as an etching component, and water, an organic solvent, etc. as other components. preferable.
  • the method for manufacturing a solar cell of the present invention may include a back surface forming step.
  • a back surface forming step For example, when forming a p-type impurity diffusion layer with two or more levels of different impurity concentrations on the substrate surface and forming an n-type impurity diffusion layer on the back surface, the surface is covered with a SiO 2 film so as to prevent n-type impurities from entering the surface. etc. to protect.
  • a preferable film thickness for obtaining a protective effect is 100 to 1000 nm, and in order to suppress the influence on the p-type diffusion layer on the substrate surface, it is preferably formed by plasma CVD with a high deposition rate at a low temperature. More specifically, the mixed gas flow rate ratio SiH 4 /N 2 O is 0.01 to 5.0, the pressure in the reaction chamber is 0.1 to 4 Torr, and the temperature during film formation is 300° C. to 550° C. formed by
  • the semiconductor substrate is heated at 800 to 900° C. in an atmosphere containing impurity diffusion components by bubbling phosphorus oxychloride (POCl 3 ) to the rear surface and flowing N 2 .
  • an n-type impurity diffusion layer is formed on the back surface of the substrate, and at the same time, a layer containing silicon oxide, such as a phosphosilicate glass layer, is formed on the outermost portion of the back surface by oxidation.
  • the inorganic film on the substrate surface and the layer containing silicon oxide on the back surface are removed by etching.
  • Specific examples of preferred etching are the same as those for forming impurity diffusion layers with two or more levels of different impurity concentrations.
  • passivation films for suppressing surface recombination and preventing light reflection may be provided on the front and back surfaces of the semiconductor substrate after the etching step, if there is a back surface forming step.
  • a passivation film for the p-type diffusion layer SiO 2 obtained by heat treatment in a high-temperature oxygen atmosphere at 700° C. or higher and a silicon nitride film for protecting this film may be provided.
  • SiNx film may be formed. In this case, it can be formed by a plasma CVD method using a mixed gas of SiH 4 and NH 3 as a raw material.
  • hydrogen diffuses into the crystal, and orbitals that do not contribute to the bonding of silicon atoms, ie, dangling bonds, bond with hydrogen to deactivate defects (hydrogen passivation). More specifically, under the conditions that the mixed gas flow rate ratio NH 3 /SiH 4 is 0.05 to 5.0, the pressure in the reaction chamber is 0.1 to 4 Torr, and the temperature during film formation is 300° C. to 550° C. It is formed.
  • a metal paste is printed by a screen printing method so as to be on the high-concentration impurity diffusion layer among the two levels of impurity diffusion layers, and dried to form an electrode.
  • the metal paste for electrodes contains metal particles and glass particles as essential components, and if necessary, a resin binder, other additives, and the like. Ag and Al are preferably used as the metal particles used at this time.
  • Electrode baking process The electrodes are then heat treated (fired) to complete the solar cell.
  • heat-treated (fired) in the range of 600° C. to 900° C. for several seconds to several minutes, the glass particles contained in the electrode metal paste melt the antireflection film, which is an insulating film, on the light-receiving surface side, and the silicon surface is also partially melted.
  • metal particles (for example, silver particles) in the paste form contact portions with the semiconductor substrate and solidify. As a result, the formed light-receiving surface electrode and the semiconductor substrate are electrically connected. This is called fire-through.
  • the light-receiving surface electrodes are generally composed of busbar electrodes and finger electrodes intersecting the busbar electrodes.
  • Such a light-receiving surface electrode can be formed by means such as screen printing of the metal paste described above, plating of an electrode material, vapor deposition of an electrode material by electron beam heating in a high vacuum, or the like.
  • the busbar electrodes and finger electrodes can be formed by a known method.
  • the method for manufacturing a solar cell of the present invention is not limited to the above-described embodiments, and modifications such as various design changes can be made based on the knowledge of those skilled in the art. Such embodiments are also included in the scope of the present invention.
  • a substrate As a substrate, a semiconductor substrate (silicon wafer) made of n-type single crystal silicon with a side of 156 mm was prepared, and alkali etching was performed on both surfaces in order to remove slice damage and natural oxide. At this time, countless irregularities (textures) typically having a width of 40 to 100 ⁇ m and a depth of 3 to 4 ⁇ m were formed on both surfaces of the semiconductor substrate, and this was used as a coated substrate.
  • silicon wafer silicon wafer
  • alkali etching was performed on both surfaces in order to remove slice damage and natural oxide.
  • countless irregularities (textures) typically having a width of 40 to 100 ⁇ m and a depth of 3 to 4 ⁇ m were formed on both surfaces of the semiconductor substrate, and this was used as a coated substrate.
  • the substrate was heated at 200° C. for 10 minutes in air to form an impurity diffusion composition film having a thickness of about 3.5 ⁇ m.
  • each substrate was immersed in a 5% by weight hydrofluoric acid aqueous solution at 23° C. for 1 minute to remove the impurity diffusion composition film. After the removal, the substrate was immersed in pure water and washed, and the presence or absence of residue was visually observed on the surface. After immersion for 1 minute, surface deposits can be visually confirmed, but can be removed by rubbing with a waste cloth. When the surface deposits could not be visually confirmed, it was rated as A, and B or higher was rated as acceptable.
  • the substrate after impurity diffusion used for residue evaluation is p/n judged using a p / n judgment machine, and the surface resistance is measured by a four-probe type surface resistance measurement device RT-70V (Napson (manufactured by Co., Ltd.). This measurement was performed on a total of 13 points of data at intervals of 20 mm in the vertical and horizontal directions from the center of the square substrate, and the average value was evaluated as the sheet resistance value, and the variation in the values was evaluated as the uniformity of the resistance value.
  • the sheet resistance value is an index of impurity diffusibility, and a smaller value means a larger amount of impurity diffusion. The smaller the variation in the value indicating the uniformity of the resistance value, the better, and the value within 20% above and below the average value was considered acceptable.
  • the same screen printer as used for residue evaluation was used, and the screen mask had an opening with a width of 70 ⁇ m and a length of 13.5 cm on the center line of the substrate (parallel to the side of the substrate).
  • Seven striped parallel patterns were formed by using 3 strips (400 mesh, wire diameter 23 ⁇ m, manufactured by SUS Co., Ltd.), 3 strips on each side of the strip, which were sandwiched in parallel with each other at intervals of 1 cm.
  • the substrate was heated at 200° C. for 10 minutes in air to form a pattern with a thickness of about 3.5 ⁇ m.
  • the width of the pattern printed with the 70 ⁇ m mask was actually measured using a microscope (MX61L manufactured by Olympus Corporation), and how much the pattern spread with respect to the 70 ⁇ m mask was evaluated.
  • a curing liquid prepared by dissolving 0.6 equivalent of piperazine in 8 cc of water was added to the uncured epoxy emulsion, and the mixture was gently stirred to homogenize. This liquid was allowed to stand at 25° C. for 3 days to cure into a spherical filler having an average particle size of about 6 ⁇ m.
  • the filler collected by filtration was placed in an eggplant-shaped flask, and 400 g of acetonitrile (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added to re-disperse. A condenser was attached to this, and extraction was performed for 8 hours in a water bath at 50° C. while heating and stirring to refine the filler. After cooling, the organic filler B was obtained by suction filtration and drying under reduced pressure at 50° C. for 8 hours.
  • Example 1 1.5 g of boric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 5.0 g of polyvinyl alcohol (manufactured by Nippon Acetate & Poval Co., Ltd.) with a degree of saponification of 80% (hereinafter referred to as PVA (80)) Then, 40.0 g of organic filler A, 34.0 g of 3-methoxy-3-methyl-1-butanol (manufactured by Tokyo Kasei Co., Ltd.) (hereinafter referred to as MMB), and 20.0 g of water are mixed and uniform. A p-type impurity diffused composition 1 was obtained by sufficiently stirring as above.
  • Example 2 A p-type impurity diffusion composition 2 was obtained in the same manner as in Example 1 except that the organic filler B was used instead of the organic filler A.
  • Example 3 A p-type impurity diffusion composition 3 was obtained in the same manner as in Example 1 except that the organic filler C was used instead of the organic filler A.
  • Example 1 A p-type impurity diffusion composition 4 was obtained in the same manner as in Example 1 except that the organic filler D was used instead of the organic filler A.
  • Example 2 A p-type impurity diffusion composition 5 was obtained in the same manner as in Example 1 except that a silica filler (SO-E2: manufactured by Admatechs Co., Ltd.) was used instead of the organic filler A.
  • a silica filler SO-E2: manufactured by Admatechs Co., Ltd.
  • Example 4 Instead of 5.0 g of PVA (80), 12.5 g of polyvinyl alcohol having a degree of saponification of 10% (manufactured by Nippon Vinyl Poval Co., Ltd.) (hereinafter referred to as PVA (10)), 34.0 g of MMB and 20.0 g of water.
  • P-type impurity diffusion composition 7 was prepared in the same manner as in Example 1, except that 27.0 g of terpineol (manufactured by Tokyo Kasei Co., Ltd.) (hereinafter referred to as TP), 11.0 g of MMB, and 10.0 g of water were used instead of 0 g. got
  • Example 5 Example 4 except that instead of 12.5 g of PVA (10), 10.0 g of polyvinyl alcohol (manufactured by Nippon Acetate & Poval Co., Ltd.) having a degree of saponification of 49% (hereinafter referred to as PVA (49)) was used.
  • PVA (49) polyvinyl alcohol having a degree of saponification of 49%
  • Example 6 10.0 g of PVA (49) in place of 5.0 g of PVA (80), 27.0 g of TP in place of 34.0 g of MMB and 20.0 g of water, and 1,3-propanediol (hereinafter referred to as 1,3-PD) 11
  • 1,3-PD 1,3-propanediol
  • Example 7 A p-type impurity diffusion composition 10 was prepared in the same manner as in Example 1 except that polyethylene glycol 400 (manufactured by Tokyo Kasei Co., Ltd.) was used instead of PVA (80) and organic filler B was used instead of organic filler A. Obtained.
  • Evaluations (1) to (5) were performed on the obtained p-type impurity diffusion compositions of Examples 1 to 7 and Comparative Examples 1 to 3. Table 2 shows the evaluation results.

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Abstract

L'invention concerne une composition à diffusion d'impuretés de type p avec laquelle un motif peut être aminci. La composition à diffusion d'impuretés de type p contient (A) un composé d'élément du groupe 13, (B) une haute molécule contenant un groupe hydroxyle, et (C) une charge organique composée d'un polymère réticulé.
PCT/JP2022/038911 2021-11-05 2022-10-19 Composition à diffusion d'impuretés de type p et procédé de production d'une cellule solaire l'utilisant WO2023079957A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2794846A (en) * 1955-06-28 1957-06-04 Bell Telephone Labor Inc Fabrication of semiconductor devices
JP2012234990A (ja) * 2011-05-02 2012-11-29 Hitachi Chem Co Ltd ｐ型拡散層形成組成物、ｐ型拡散層の製造方法、及び太陽電池素子の製造方法
JP2013501381A (ja) * 2009-08-04 2013-01-10 プリカーサー エナジェティクス， インコーポレイテッド 制御された化学量論を有する光起電性アブソーバーのための方法
JP2016189485A (ja) * 2012-02-23 2016-11-04 日立化成株式会社 ｎ型拡散層形成組成物、ｎ型拡散層を有する半導体基板の製造方法、及び太陽電池素子の製造方法
JP2018174276A (ja) * 2017-03-31 2018-11-08 日立化成株式会社 ｐ型拡散層付き半導体基板の製造方法、ｐ型拡散層付き半導体基板、太陽電池素子、及び太陽電池素子の製造方法
WO2020116340A1 (fr) * 2018-12-07 2020-06-11 東レ株式会社 Procédé de production d'élément semi-conducteur et procédé de production de cellule solaire

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2794846A (en) * 1955-06-28 1957-06-04 Bell Telephone Labor Inc Fabrication of semiconductor devices
JP2013501381A (ja) * 2009-08-04 2013-01-10 プリカーサー エナジェティクス， インコーポレイテッド 制御された化学量論を有する光起電性アブソーバーのための方法
JP2012234990A (ja) * 2011-05-02 2012-11-29 Hitachi Chem Co Ltd ｐ型拡散層形成組成物、ｐ型拡散層の製造方法、及び太陽電池素子の製造方法
JP2016189485A (ja) * 2012-02-23 2016-11-04 日立化成株式会社 ｎ型拡散層形成組成物、ｎ型拡散層を有する半導体基板の製造方法、及び太陽電池素子の製造方法
JP2018174276A (ja) * 2017-03-31 2018-11-08 日立化成株式会社 ｐ型拡散層付き半導体基板の製造方法、ｐ型拡散層付き半導体基板、太陽電池素子、及び太陽電池素子の製造方法
WO2020116340A1 (fr) * 2018-12-07 2020-06-11 東レ株式会社 Procédé de production d'élément semi-conducteur et procédé de production de cellule solaire

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