WO2013105602A1 - n-TYPE DIFFUSION LAYER FORMING COMPOSITION, n-TYPE DIFFUSION LAYER FORMING COMPOSITION SET, PRODUCTION METHOD FOR SEMICONDUCTOR SUBSTRATE HAVING n-TYPE DIFFUSION LAYER, AND PRODUCTION METHOD FOR SOLAR CELL ELEMENT - Google Patents

n-TYPE DIFFUSION LAYER FORMING COMPOSITION, n-TYPE DIFFUSION LAYER FORMING COMPOSITION SET, PRODUCTION METHOD FOR SEMICONDUCTOR SUBSTRATE HAVING n-TYPE DIFFUSION LAYER, AND PRODUCTION METHOD FOR SOLAR CELL ELEMENT Download PDF

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WO2013105602A1
WO2013105602A1 PCT/JP2013/050303 JP2013050303W WO2013105602A1 WO 2013105602 A1 WO2013105602 A1 WO 2013105602A1 JP 2013050303 W JP2013050303 W JP 2013050303W WO 2013105602 A1 WO2013105602 A1 WO 2013105602A1
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type diffusion
diffusion layer
forming composition
composition
layer forming
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PCT/JP2013/050303
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French (fr)
Japanese (ja)
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明博 織田
吉田　誠人
野尻　剛
倉田　靖
洋一 町井
岩室　光則
麻理 清水
鉄也 佐藤
芦沢　寅之助
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日立化成株式会社
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Priority to JP2013553307A priority Critical patent/JP5892178B2/en
Priority to CN201380005051.7A priority patent/CN104081499A/en
Publication of WO2013105602A1 publication Critical patent/WO2013105602A1/en

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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
    • H01L21/2225—Diffusion sources
    • 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
    • H01L21/2251—Diffusion into or out of group IV semiconductors
    • H01L21/2254—Diffusion into or out of group IV semiconductors from or through or into an applied layer, e.g. photoresist, nitrides
    • H01L21/2255—Diffusion into or out of group IV semiconductors from or through or into an applied layer, e.g. photoresist, nitrides the applied layer comprising oxides only, e.g. P2O5, PSG, H3BO3, doped oxides
    • 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
    • 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
    • H01L31/0682—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 back-junction, i.e. rearside emitter, solar cells, e.g. interdigitated base-emitter regions back-junction cells
    • 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
    • H01L31/1804—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof comprising only elements of Group IV of the Periodic Table
    • 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 present invention relates to an n-type diffusion layer forming composition, an n-type diffusion layer forming composition set, a method for manufacturing a semiconductor substrate with an n-type diffusion layer, and a method for manufacturing a solar cell element.
  • a p-type silicon substrate having a textured structure formed on the light receiving surface is prepared so as to promote the light confinement effect, and then in a mixed gas atmosphere of phosphorus oxychloride (POCl 3 ), nitrogen, and oxygen.
  • An n-type diffusion layer is uniformly formed by performing several tens of minutes at 800 ° C. to 900 ° C.
  • n-type diffusion layers are formed not only on the surface but also on the side surface and the back surface. Therefore, a side etching process for removing the side n-type diffusion layer is necessary.
  • the n-type diffusion layer on the back surface needs to be converted into a p + -type diffusion layer. Therefore, after applying an aluminum paste containing aluminum as a group 13 element on the n-type diffusion layer on the back surface, heat treatment is performed, and at the same time the n-type diffusion layer is converted to the p + -type diffusion layer by the diffusion of aluminum. , Got ohmic contact.
  • an n-type diffusion layer forming composition containing a glass powder containing a donor element and a dispersion medium is applied to a semiconductor substrate and subjected to thermal diffusion treatment, so that it is unnecessary on the side surface or back surface of the semiconductor substrate.
  • a method for manufacturing a solar cell element in which an n-type diffusion layer is formed in a specific region without forming an n-type diffusion layer has been proposed (see, for example, International Publication No. 2011/090216 pamphlet).
  • the diffusion in the region other than directly under the electrode is compared with the diffusion concentration of the donor element in the region directly under the electrode (hereinafter also simply referred to as “diffusion concentration”).
  • diffusion concentration the diffusion concentration of the donor element in the region directly under the electrode
  • a selective emitter structure with a low concentration is known (see, for example, L. Debarge, M. Schott, JCMuller, R.Monna, Solar Energy Materials and Solar Cells 74 (2002) 71-75).
  • this region is also referred to as “selective emitter” is formed, so that the contact resistance between the electrode and silicon can be reduced.
  • the diffusion concentration is relatively low except in the region where the electrode is formed, the conversion efficiency of the solar cell element can be improved.
  • the present invention has been made in view of the above-described conventional problems, and an n-type diffusion layer can be formed in a specific region, and the diffusion concentration of a donor element in the formed n-type diffusion layer can be easily achieved. It is an object of the present invention to provide an n-type diffusion layer forming composition that can be adjusted to the above, a method for manufacturing a semiconductor substrate with an n-type diffusion layer using the composition, and a method for manufacturing a solar cell element.
  • a compound containing a donor element is different from the compound containing a donor element, and a metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal, and a dispersion And an n-type diffusion layer forming composition containing the medium.
  • the compound containing the donor element is the n-type diffusion layer forming composition according to ⁇ 1>, which is a compound containing P (phosphorus).
  • the metal compound is a compound containing at least one metal element selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium ⁇ 1 > Or ⁇ 2>.
  • the n-type diffusion layer forming composition is a compound containing at least one metal element selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium ⁇ 1 > Or ⁇ 2>.
  • n-type diffusion layer forming composition according to any one of ⁇ 1> to ⁇ 3>, wherein the content of the metal compound is 0.01% by mass or more and 50% by mass or less.
  • the metal compound is a solid particle at normal temperature, and the volume average particle diameter of the particle is 0.01 ⁇ m or more and 30 ⁇ m or less. This is a mold diffusion layer forming composition.
  • ⁇ 6> The compound according to any one of ⁇ 1> to ⁇ 5>, wherein the compound containing the donor element is a compound containing at least one selected from the group consisting of P 2 O 3 and P 2 O 5.
  • the n-type diffusion layer forming composition is a compound containing at least one selected from the group consisting of P 2 O 3 and P 2 O 5.
  • the compound containing a donor element is the n-type diffusion layer forming composition according to any one of ⁇ 1> to ⁇ 6>, which is in the form of glass particles.
  • At least one donor element-containing material selected from the group consisting of P 2 O 3 and P 2 O 5 , SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO.
  • containing at least one glass component material selected from the group consisting of SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V 2 O 5 , SnO, ZrO 2 and MoO 3 Is an n-type diffusion layer forming composition.
  • n-type diffusion layer forming composition according to ⁇ 7> or ⁇ 8> wherein the glass particle content is 1% by mass or more and 80% by mass or less.
  • ⁇ 10> The content according to any one of ⁇ 7> to ⁇ 9>, wherein the total content of P 2 O 3 and P 2 O 5 in the glass particles is 0.01% by mass or more and 10% by mass or less. It is an n-type diffusion layer forming composition.
  • n-type diffusion layer forming composition according to any one of ⁇ 1> to ⁇ 10>, further including an organic binder.
  • ⁇ 12> A step of forming a composition layer by applying the n-type diffusion layer forming composition according to any one of ⁇ 1> to ⁇ 11> to the entire surface or a part of a semiconductor substrate; And a step of performing a heat treatment on the semiconductor substrate on which the composition layer is formed.
  • a step of forming a first composition layer by applying a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium to a partial region on a semiconductor substrate. And the step of forming the n-type diffusion layer forming composition layer is on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate, and the first composition layer
  • the first n-type diffusion layer forming composition has a content of a metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in a region different from the region where the first n-type diffusion layer is formed. It is a manufacturing method of the semiconductor substrate with an n-type diffused layer as described in said ⁇ 12> which is a process of providing the said n-type diffused layer formation composition larger than this.
  • ⁇ 14> forming a first composition layer by applying a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium to a partial region on a semiconductor substrate; ⁇ 1> to ⁇ 11 in a region different from a region where the first composition layer is formed on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate.
  • the n-type diffusion layer forming composition according to any one of the above, wherein the content of the metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal is the first Applying a second n-type diffusion layer forming composition larger than the n-type diffusion layer forming composition to form a second composition layer, and the first composition layer and the second composition
  • the semiconductor substrate on which the layer is formed is subjected to a thermal diffusion treatment, and the second on the semiconductor substrate
  • the n + -type diffusion layer in a region where the composition layer is formed of, n ++ type diffusion layer having the n + -type diffusion small surface sheet resistance than layer on the first composition layer is formed regions Are respectively formed, and a step of forming an electrode on the n ++ type diffusion layer.
  • the content of the metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in the first n-type diffusion layer forming composition is 10% by mass or less.
  • the content of the metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals in the second n-type diffusion layer forming composition is 0.01% by mass or more and 50% by mass.
  • % Is the method for producing a solar cell element according to ⁇ 14>.
  • ⁇ 16> Forming a composition layer on a semiconductor substrate by applying at least one of the n-type diffusion layer forming composition according to any one of ⁇ 1> to ⁇ 11>, and the composition
  • This is a method for manufacturing a solar cell element, which includes a step of forming a n-type diffusion layer by subjecting a semiconductor substrate on which a physical layer is formed to a thermal diffusion treatment and a step of forming an electrode on the n-type diffusion layer.
  • An n-type diffusion layer forming composition set comprising a layer forming composition.
  • an n-type diffusion layer can be formed in a specific region, and the diffusion concentration of the donor element in the formed n-type diffusion layer can be easily adjusted.
  • a forming composition, a method for producing a semiconductor substrate with an n-type diffusion layer using the composition, and a method for producing a solar cell element can be provided.
  • an n-type diffusion layer forming composition of the present invention will be described, and then a method for manufacturing a semiconductor substrate with an n-type diffusion layer and a solar cell element using the n-type diffusion layer forming composition will be described.
  • the term “process” is not limited to an independent process, and even if it cannot be clearly distinguished from other processes, the term “process” is used if the intended purpose of the process is achieved. included.
  • a numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
  • the amount of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition.
  • content rate represents the mass% of the component with respect to 100 mass% of n type diffused layer formation compositions, unless there is particular description.
  • the n-type diffusion layer forming composition of the present invention is a compound (A) containing a donor element and a compound different from the compound containing a donor element (at least selected from the group consisting of alkaline earth metals and alkali metals). It contains a metal compound (B) containing one kind of metal element and a dispersion medium (C), and may contain other additives as required in consideration of coating properties and the like.
  • the n-type diffusion layer forming composition of the present invention comprises a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals (hereinafter referred to as “specific”) in addition to the compound containing a donor element.
  • the diffusibility of the donor element into the semiconductor substrate can be suppressed as compared with the case of using the n-type diffusion layer forming composition not containing the specific compound. Therefore, for example, in the semiconductor substrate, the n-type diffusion layer forming composition of the present invention is applied to a region where the diffusion concentration of the donor element is desired to be adjusted to be lower than other regions, and the n-type diffusion layer formation containing no specific compound is performed in the other regions.
  • the thermal diffusion treatment with the composition the diffusion concentration of the donor element in a desired region can be easily adjusted to be low. That is, it is possible to easily form a region where the diffusion concentration of the donor element is selectively different in the same plane of the semiconductor substrate. The reason for this can be considered as follows.
  • P 2 O 5 (or a material that changes to a compound containing P 2 O 5 at 800 ° C. or higher) and P 2 O 3 that are preferably used as a compound containing a donor element are both acidic oxides. These are believed to diffuse into the semiconductor substrate as P 2 O 5 or P 2 O 3 .
  • the specific compound is contained in the n-type diffusion layer forming composition, the reactivity between the compound containing the donor element and the specific compound is higher than the reactivity between the compound containing the donor element and the semiconductor substrate. It is considered that the diffusibility of the donor element into the semiconductor substrate can be suppressed.
  • the specific compound is a basic compound
  • an acid-base reaction occurs between the specific compound and the compound containing the donor element, and the acid-base reaction is highly reactive, so the semiconductor substrate of the donor element is more effective. It is thought that diffusion into the inside can be suppressed.
  • the specific compound is stable even at a high temperature (for example, 500 ° C. or higher), so that the effect of the present invention can be sufficiently exerted when the donor element is diffused into the semiconductor substrate. Furthermore, even when the specific compound is dissolved in the semiconductor substrate, it does not act as a carrier recombination center in the semiconductor substrate, so that it is possible to suppress the occurrence of a problem that the conversion efficiency is lowered when the semiconductor substrate is applied to a solar cell. .
  • the diffusion concentration of the donor element into the semiconductor substrate can be adjusted more precisely. Furthermore, by including the specific compound, out diffusion can be suppressed even if the compound containing the donor element is a highly volatile compound. This is considered to be because, for example, the volatility of the compound containing the donor element is suppressed by the chemical interaction of the specific compound with the compound containing the donor element.
  • the present invention provides a selective emitter structure that has conventionally required a complicated manufacturing process combining a plurality of thermal diffusion processes and partial etching by masking, etc., with a simple manufacturing process, for example, a single thermal diffusion process. It has the effect of making it possible to form.
  • a donor element is an element capable of forming an n-type diffusion layer by thermal diffusion in a semiconductor substrate.
  • the donor element a Group 15 element can be used, and P (phosphorus) is preferable from the viewpoint of safety and the like.
  • P phosphorus
  • a metal oxide containing a donor element a single metal oxide such as P 2 O 5 or P 2 O 3 ; phosphorous silicide, silicon particles doped with phosphorus, calcium phosphate, phosphoric acid, phosphorus-containing glass particles, etc.
  • the organic phosphorus compound is a compound that can be changed to a compound containing P 2 O 5 at a high temperature (for example, 800 ° C. or higher) at which the donor element thermally diffuses into the semiconductor substrate.
  • a compound for example, ammonium dihydrogen phosphate
  • a compound containing P 2 O 5 at a high temperature for example, 800 ° C. or more
  • P 2 O 3 , P 2 O 5 and a donor element are thermally diffused into a semiconductor substrate.
  • the melting point is 1000. It is more preferable to use a compound having a temperature of 0 ° C. or lower.
  • the donor element can be uniformly thermally diffused to the semiconductor substrate. Even if the compound has a melting point of more than 1000 ° C., a compound having a melting point of less than 1000 ° C. is further added to the semiconductor substrate from the compound containing the donor element to the semiconductor substrate through the compound having a melting point of less than 1000 ° C. The element may be thermally diffused.
  • the compound containing the donor element in the n-type diffusion layer forming composition is in the form of particles at normal temperature (25 ° C.), the shape in the case of particles is approximately spherical, flat, block, plate, scale, etc. Is mentioned. From the viewpoint of the coating property to the substrate and the uniform diffusibility when the n-type diffusion layer forming composition is used, the composition is preferably substantially spherical, flat or plate-like.
  • the particle diameter of the particles is preferably 100 ⁇ m or less. When particles having a particle size of 100 ⁇ m or less are used, a smooth composition layer is easily obtained.
  • the particle diameter of the particles is more preferably 50 ⁇ m or less.
  • grains in case the compound containing a donor element is a solid particle form represents a volume average particle diameter, and can be measured with a laser scattering diffraction method particle size distribution measuring apparatus. The volume average particle diameter can be calculated based on the Mie scattering theory by detecting the relationship between the scattered light intensity and the angle of the laser light applied to the particles.
  • the dispersion medium which the particle
  • the compound containing the donor element may be in a state dissolved in the dispersion medium, and in that case, the shape and particle size of the compound containing the donor element used for preparing the n-type diffusion layer forming composition are not particularly limited.
  • the content rate of the compound containing the donor element in the n-type diffusion layer forming composition is determined in consideration of the coating property, the diffusibility of the donor element, and the like.
  • the content of the compound containing a donor element in the n-type diffusion layer forming composition is preferably 0.1% by mass or more and 95% by mass or less in the n-type diffusion layer forming composition. % To 90% by mass, more preferably 1% to 80% by mass, further preferably 2% to 80% by mass, and more preferably 5% to 20% by mass. It is particularly preferred that When the content of the compound containing a donor element is 0.1% by mass or more, the n-type diffusion layer can be sufficiently formed. When the content is 95% by mass or less, the dispersibility of the compound containing the donor element in the n-type diffusion layer forming composition is improved, and the coating property to the semiconductor substrate is improved.
  • the compound containing a donor element is preferably a glass particle containing a donor element.
  • glass refers to a substance that has no irregular crystal structure in its X-ray diffraction spectrum, has an irregular network structure, and exhibits a glass transition phenomenon.
  • out-diffusion the diffusion of the donor element to a region other than the region to which the n-type diffusion layer forming composition is applied
  • out-diffusion the diffusion of the donor element to a region other than the region to which the n-type diffusion layer forming composition is applied
  • the formation of an unnecessary n-type diffusion layer can be suppressed. That is, an n-type diffusion layer can be formed more selectively by including glass particles containing a donor element.
  • the glass particles containing the donor element will be described in detail.
  • the glass particles contained in the n-type diffusion layer forming composition of the present invention are melted at a firing temperature (about 800 ° C. to 2000 ° C.) during thermal diffusion to form a glass layer on the n-type diffusion layer. To do. Therefore, out diffusion can be further suppressed.
  • the glass layer formed on the n-type diffusion layer can be removed by etching (hydrofluoric acid aqueous solution or the like).
  • the glass particles containing a donor element can be formed including, for example, a donor element-containing material and a glass component material.
  • the donor element-containing material used for introducing the donor element into the glass particles is preferably a compound containing P (phosphorus), and at least one selected from the group consisting of P 2 O 3 and P 2 O 5 More preferably.
  • the content of the donor element-containing substance in the glass particles containing the donor element is not particularly limited. For example, from the viewpoint of the diffusibility of the donor element, the content is preferably 0.5% by mass or more and 100% by mass or less, and more preferably 2% by mass or more and 80% by mass or less.
  • the glass particle containing the donor element contains 0.5% by mass or more of at least one selected from the group consisting of P 2 O 3 and P 2 O 5 as a donor element-containing substance from the viewpoint of diffusibility of the donor element. It is preferably contained in an amount of not more than mass%, more preferably not less than 2 mass% and not more than 80 mass%.
  • the glass particle containing a donor element can control a melting temperature, a softening point, a glass transition point, chemical durability, etc. by adjusting the component ratio as needed. Furthermore, it is preferable to contain at least 1 sort (s) of the glass component material described below.
  • the glass component materials include SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, Tl 2 O, V 2 O 5 , SnO, and WO 3.
  • the glass particles containing a donor element include a system containing both the donor element-containing substance and the glass component substance.
  • P 2 O 5 —SiO 2 system in the order of donor element-containing material—glass component material, the same shall apply hereinafter
  • glass particles containing two or more kinds of donor element-containing substances such as P 2 O 5 —Sb 2 O 3 series, P 2 O 5 —As 2 O 3 series, and the like may be used.
  • a composite glass containing two components is exemplified, but glass particles containing three or more components such as P 2 O 5 —SiO 2 —V 2 O 5 and P 2 O 5 —SiO 2 —CaO may be used.
  • the glass particles include at least one donor element-containing material selected from the group consisting of P 2 O 3 and P 2 O 5 , SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO, SrO, At least one glass selected from the group consisting of CaO, MgO, BeO, ZnO, PbO, CdO, V 2 O 5 , SnO, ZrO 2 , MoO 3 , GeO 2 , Y 2 O 3 , CsO 2 and TiO 2.
  • a donor element-containing material selected from the group consisting of P 2 O 3 and P 2 O 5 , and SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V 2 O 5, SnO, at least one glass selected from the group consisting of ZrO 2 and MoO 3 More preferably containing a minute substance, a donor element-containing material is a P 2 O 5, SiO 2, ZnO, CaO, Na 2 O, at least one selected from the group consisting of Li 2 O and BaO It is more preferable to contain these glass component substances. Thereby, the sheet resistance of the n-type diffusion layer to be formed can be further reduced.
  • the content ratio of the glass component material selected from the group consisting of SiO 2 and GeO 2 in the glass particles is the melting temperature, softening point, glass transition point, chemical durability. It is preferable to set appropriately considering the above.
  • the specific glass component substance is preferably 0.01% by mass or more and 80% by mass or less, and more preferably 0.1% by mass or more and 50% by mass or less in 100% by mass of the glass particles.
  • An n-type diffused layer can be efficiently formed as it is 0.01 mass% or more. Moreover, formation of the n-type diffusion layer in the part which has not provided the n-type diffusion layer formation composition as it is 80 mass% or less can be suppressed more effectively.
  • the glass particles may contain a network-modified oxide (for example, alkali oxide or alkaline earth oxide) or an intermediate oxide that does not vitrify alone.
  • a network-modified oxide for example, alkali oxide or alkaline earth oxide
  • the content ratio of CaO that is a network modification oxide is preferably 1% by mass to 30% by mass, and preferably 5% by mass. More preferably, it is 20 mass% or less.
  • the softening point of the glass particles is preferably 200 ° C. to 1000 ° C., more preferably 300 ° C. to 900 ° C., from the viewpoints of diffusibility and dripping during the diffusion treatment.
  • the softening point of the glass particles can be obtained from a differential heat (DTA) curve using a differential heat / thermogravimetric simultaneous measurement apparatus. Specifically, the value of the third peak from the low temperature of the DTA curve can be set as the softening point.
  • Glass particles containing a donor element are produced by the following procedure.
  • raw materials for example, the donor element-containing material and the glass component material are weighed and filled in a crucible.
  • the material for the crucible include platinum, platinum-rhodium, iridium, alumina, quartz, carbon, and the like, and are appropriately selected in consideration of the melting temperature, atmosphere, reactivity with the molten material, and the like.
  • it heats with the temperature according to a glass composition with an electric furnace, and is set as a melt. At this time, stirring is preferably performed so that the melt becomes uniform.
  • the obtained melt is poured onto a zirconia substrate, a carbon substrate, or the like to vitrify the melt.
  • the glass is pulverized into powder.
  • a known method such as a jet mill, a bead mill, or a ball mill can be applied to the pulverization.
  • the content of the donor element in the glass particles is 0.01% by mass or more and 40% by mass or less in the glass particles from the viewpoint of diffusion performance. Preferably, it is 0.1 to 35% by mass, more preferably 1 to 30% by mass.
  • the content rate of the glass particle in an n type diffused layer formation composition is in an n type diffused layer formation composition from a viewpoint of the uniformity of diffusion. It is preferably 1% by mass or more and 80% by mass or less, more preferably 5% by mass or more and 60% by mass or less, and further preferably 10% by mass or more and 40% by mass or less.
  • the n-type diffusion layer forming composition of the present invention is a compound different from the compound containing the donor element. And at least one metal compound (specific compound) containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals. Thereby, the diffusion concentration of the donor element to the semiconductor substrate can be easily controlled.
  • an n-type diffusion layer forming composition containing a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals is used.
  • the diffusion concentration of the donor element is higher than when the n-type diffusion layer forming composition not containing a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals is used.
  • An n-type diffusion layer having a low thickness can be formed.
  • the specific compound (B) is a compound different from the compound (A) containing the donor element, for example, the compound (A) containing the donor element is a glass particle, and the glass component constituting the glass particle Even when an alkaline earth metal or a compound containing an alkali metal is contained as a substance, the n-type diffusion layer forming composition of the present invention is independent of the compound (A) containing the specific compound (B) and the donor element. Is meant to be contained.
  • the metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals may be a liquid at room temperature (about 20 ° C.) or a solid. Since the thermal diffusion temperature of the donor element is high, it is preferably a solid compound at a high temperature (for example, 500 ° C. or higher) at which thermal diffusion treatment is performed.
  • the metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals is at least one type selected from the group consisting of alkaline earth metals and alkali metals.
  • metal salts containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals are examples of metal salts containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals.
  • a metal compound (specific compound) containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal changes to a basic compound at a high temperature of 700 ° C. or higher at which a donor element is thermally diffused.
  • a compound is preferred.
  • the specific compound is at least one metal element selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium as the metal element. It is preferable to contain at least one metal element selected from the group consisting of magnesium, calcium, potassium and barium, and at least one selected from the group consisting of magnesium, calcium and potassium It is more preferable to contain these metal elements.
  • the specific compound is selected from metal oxides, metal carbonates, metal nitrates, metal sulfates and metal hydroxides containing at least one selected from the group consisting of these metal elements. It is preferably at least one selected from the group consisting of, and particularly preferably at least one selected from the group consisting of metal oxides, metal carbonates, and metal hydroxides.
  • Specific compounds include metal oxides such as sodium oxide, potassium oxide, lithium oxide, calcium oxide, magnesium oxide, rubidium oxide, cesium oxide, beryllium oxide, strontium oxide, barium oxide, radium oxide, and complex oxides thereof.
  • Metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, beryllium hydroxide, strontium hydroxide, barium hydroxide, radium hydroxide
  • Metal carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, calcium carbonate, magnesium carbonate, rubidium carbonate, cesium carbonate, beryllium carbonate, strontium carbonate, barium carbonate, radium carbonate; sodium nitrate, potassium nitrate, lithium nitrate Metal nitrates such as sodium, calcium sulfate, magnesium nitrate, rubidium nitrate, cesium nitrate, beryllium n
  • the specific compounds are sodium carbonate, sodium oxide, potassium carbonate, potassium oxide, calcium carbonate, calcium hydroxide, calcium oxide, magnesium carbonate, magnesium hydroxide, magnesium sulfate from the viewpoint of low toxicity and availability.
  • at least one selected from the group consisting of calcium sulfate, magnesium nitrate, calcium nitrate and magnesium oxide is used, and potassium carbonate, potassium oxide, magnesium oxide, calcium oxide, magnesium carbonate, calcium carbonate, magnesium sulfate, sulfuric acid
  • at least one selected from the group consisting of lucium, calcium oxide, calcium hydroxide, magnesium carbonate, magnesium oxide and magnesium hydroxide is used, and potassium oxide, calcium carbonate, calcium oxide, calcium hydroxide and magnesium carbonate are more preferable. It is particularly preferable to use at least one selected from the group consisting of
  • the particle diameter of the particles is preferably 0.01 ⁇ m or more and 30 ⁇ m or less, more preferably 0.02 ⁇ m or more and 10 ⁇ m or less, and 0.03 ⁇ m or more and 5 ⁇ m or less. More preferably.
  • the particle diameter is 30 ⁇ m or less, the donor element can be uniformly diffused (doped) by the application region of the n-type diffusion layer forming composition on the semiconductor substrate. Moreover, it exists in the tendency which can disperse
  • the specific compound may be dissolved in the dispersion medium.
  • the particle diameter represents a volume average particle diameter, and can be measured with a laser scattering diffraction particle size distribution measuring apparatus or the like.
  • the method for obtaining solid particles of a specific compound having a particle diameter in a desired range for example, 0.01 ⁇ m to 30 ⁇ m.
  • it can be obtained by pulverization.
  • a grinding method a dry grinding method and a wet grinding method can be employed.
  • a jet mill, a vibration mill, a ball mill, or the like can be employed.
  • a wet pulverization method a bead mill, a ball mill or the like can be employed.
  • the lifetime of carriers in the semiconductor substrate may be reduced. It is preferable to select a material with less influence. Specifically, partially stabilized zirconia or the like can be used.
  • a desired specific compound can be obtained by using a gas phase oxidation method, a hydrolysis method, or the like.
  • the shape of the specific compound is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a scale shape, a block shape, an oval shape, a plate shape, and a rod shape.
  • the shape of a specific compound can be determined by observing using a scanning electron microscope.
  • the specific compound may be reacted in advance with a compound containing a donor element.
  • a material obtained by immersing calcium oxide in a phosphoric acid aqueous solution to fix the phosphorus compound on the surface of the calcium oxide and then separating the calcium oxide to which the phosphorus compound is fixed by filtration includes a donor element. You may use as a compound and a specific compound.
  • the content of the specific compound in the n-type diffusion layer forming composition is determined in consideration of the coating property, the diffusion concentration of the donor element into the semiconductor substrate, and the like.
  • the content of the specific compound in the n-type diffusion layer forming composition is preferably 0.01% by mass or more and 50% by mass or less in the n-type diffusion layer forming composition, and is 0.02% by mass. It is more preferably 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.
  • the content of the specific compound is 0.01% by mass or more, thermal diffusion of the donor element contained in the compound containing the donor element to the semiconductor substrate can be appropriately suppressed. Moreover, it exists in the tendency which does not inhibit the thermal diffusion to the semiconductor substrate of the donor element contained in the compound containing a donor element too much that it is 50 mass% or less.
  • the content ratio of the specific compound with respect to the compound containing a donor element in the n-type diffusion layer forming composition is not particularly limited. From the viewpoint of uniformity of diffusion of the donor element into the semiconductor substrate, it is preferably 0.01% by mass or more and 10% by mass or less, and 0.1% by mass or more and 8% by mass with respect to 100% by mass of the compound containing the donor element. % Or less, more preferably 0.5% by mass or more and 6% by mass or less.
  • the n-type diffusion layer forming composition of the present invention contains a dispersion medium.
  • the dispersion medium is a medium in which a compound containing the donor element and a metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal are dispersed or dissolved in the composition.
  • the dispersion medium preferably contains at least a solvent or water.
  • a dispersion medium in addition to a solvent or water, you may contain the organic binder mentioned later.
  • Solvents include ketone solvents; ether solvents; ester solvents such as 2- (2-butoxyethoxy) ethyl acetate; aprotic polar solvents; alcohol solvents; glycol monoether solvents such as diethylene glycol mono-n-butyl ether; ⁇ -terpinene Terpinene such as ⁇ -terpineol, pinene such as ⁇ -pinene and ⁇ -pinene, terpene solvents such as myrcene, alloocimene, limonene, dipentene, carvone, osimene, and ferrandrene.
  • the solvent those described in JP2012-084830A may be used.
  • n-type diffusion layer forming composition at least one selected from the group consisting of a terpene solvent, a glycol monoether solvent and an ester solvent is preferable from the viewpoint of applicability to the substrate.
  • a terpene solvent a glycol monoether solvent
  • an ester solvent is preferable from the viewpoint of applicability to the substrate.
  • Terpineol, diethylene glycol mono-n-butyl ether Or 2- (2-butoxyethoxy) ethyl acetate is preferred.
  • the content of the dispersion medium in the n-type diffusion layer forming composition is determined in consideration of the coating property and the concentration of the donor element.
  • it is preferably 5% by mass or more and 99% by mass or less, more preferably 20% by mass or more and 95% by mass or less, and 40% by mass or more and 90% by mass or less. More preferably it is.
  • the n-type diffusion layer forming composition of the present invention in addition to a compound containing a donor element, a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals, and a dispersion medium, If necessary, an organic binder, a surfactant, an inorganic powder, a resin containing a silicon atom, a reducing additive, a thixotropic agent, and the like can be contained.
  • the n-type diffusion layer forming composition may further contain at least one organic binder.
  • the organic binder By including the organic binder, it is possible to adjust the viscosity and impart thixotropy as the n-type diffusion layer forming composition, thereby further improving the impartability to the semiconductor substrate.
  • organic binder examples include polyvinyl alcohol; polyacrylamide resin; polyvinyl amide resin; polyvinyl pyrrolidone resin; polyethylene oxide resin; polysulfone resin; acrylamide alkyl sulfone resin; cellulose derivatives such as cellulose ether, carboxymethyl cellulose, hydroxyethyl cellulose, and ethyl cellulose; Starch and starch derivatives; sodium alginate and sodium alginate derivatives; xanthan and xanthan derivatives; gua and guar derivatives; scleroglucan and scleroglucan derivatives; tragacanth and tragacanth derivatives; Resin; alkyl (meth) acrylate resin, dimethylaminoethyl Meth) acrylates such as resin (meth) acrylic acid ester resin; butadiene resin; a styrene resin; and can select these copolymers as appropriate. These are used singly or in combination of two or more. When using
  • the molecular weight of the organic binder is not particularly limited, and is preferably adjusted appropriately in view of the desired viscosity as the composition.
  • content in the case of containing an organic binder is 0.5 mass% or more and 30 mass% or less in n type diffused layer formation composition, and is 3 mass% or more and 25 mass% or less. Is more preferable, and more preferably 3% by mass or more and 20% by mass or less.
  • the surfactant examples include a nonionic surfactant, a cationic surfactant, and an anionic surfactant.
  • nonionic surfactants or cationic surfactants are preferable because impurities such as heavy metals are not brought into the semiconductor substrate.
  • nonionic surfactants include silicon surfactants, fluorine surfactants, hydrocarbon surfactants, and the like. Of these, hydrocarbon surfactants are preferred because they are rapidly fired during heating such as diffusion.
  • hydrocarbon surfactants include ethylene oxide-propylene oxide block copolymers, acetylene glycol compounds, and the like. From the viewpoint of further reducing variation in the sheet resistance value of the semiconductor substrate, an acetylene glycol compound is preferred.
  • the inorganic powder is preferably a substance that can function as a filler.
  • examples of the inorganic powder include silicon oxide, titanium oxide, silicon nitride, and silicon carbide powder.
  • the n-type diffusion layer forming composition may contain a reducing compound.
  • reducing compounds include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, terminal alkylated products of polyalkylene glycols; monosaccharides such as glucose, fructose, and galactose, and derivatives of monosaccharides; disaccharides and disaccharides such as sucrose and maltose And polysaccharides and polysaccharide derivatives; and the like.
  • polyalkylene glycol is preferable, and polypropylene glycol is more preferable.
  • the n-type diffusion layer forming composition may contain a thixotropic agent containing a solid content.
  • thixotropy can be easily controlled, and an n-type diffusion layer forming composition for screen printing having a viscosity suitable for printing can be constituted.
  • thixotropy is controlled, bleeding or sagging from the print pattern of the n-type diffusion layer forming composition during printing can be suppressed.
  • the method for producing the n-type diffusion layer forming composition of the present invention is not particularly limited.
  • a compound containing a donor element, a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals, a dispersion medium, and components to be added as needed are blender, mixer, mortar, rotor It can obtain by mixing using etc.
  • the temperature can be, for example, 30 ° C. to 100 ° C.
  • the components contained in the n-type diffusion layer forming composition, and the content of each component are thermal analysis such as TG / DTA, spectral analysis such as NMR, IR, MALDI-MS, GC-MS, HPLC, GPC It can be confirmed using chromatographic analysis.
  • the total of the compound containing the donor element, the metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals, and the dispersion medium is preferably 1% by mass or more, more preferably 5% by mass or more in the n-type diffusion layer forming composition.
  • Preferred embodiments of the composition for forming an n-type diffusion layer of the present invention are as follows, for example. (1) A compound containing at least one selected from the group consisting of P 2 O 5 and P 2 O 3 as a donor element, magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium An n-type diffusion layer forming composition containing a metal compound containing at least one metal element selected from the group consisting of and a dispersion medium.
  • An n-type diffusion layer-forming composition containing a compound and a dispersion medium.
  • An n-type diffusion layer forming composition comprising at least one selected from the group consisting of metal compound particles having a particle size of 0.01 ⁇ m or more and 30 ⁇ m or less, and a dispersion medium.
  • At least one selected from the group consisting of P 2 O 5 and P 2 O 3 is included as a donor element, the particle diameter is 0.01 ⁇ m or more and 100 ⁇ m or less, and the content is 0.1% by mass or more and 95 Metal oxide containing glass particles having a mass% or less and at least one metal element selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium , At least one selected from the group consisting of metal carbonates, metal nitrates, metal sulfates and metal hydroxides, having a particle size of 0.01 ⁇ m or more and 30 ⁇ m or less, and a content of 0.01% by mass An n-type diffusion layer forming composition containing metal compound particles in an amount of 50% by mass or less and a dispersion medium.
  • Glass particles containing as a donor element at least one selected from the group consisting of P 2 O 5 and P 2 O 3 , magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and A metal that contains at least one metal element selected from the group consisting of radium and is at least one selected from the group consisting of metal oxides, metal carbonates, metal nitrates, metal sulfates, and metal hydroxides It is an n-type diffusion layer forming composition containing a compound and a dispersion medium, wherein the content ratio of the metal compound to the glass particles containing the donor element is 0.01% by mass or more and 10% by mass or less.
  • the n-type diffusion layer forming composition of the present invention contains substantially no other metal other than the metal contained in the compound containing the donor element and the metal contained in the specific compound (0.5% by mass or less). Is preferable, and it is more preferable not to contain a metal (0 mass%).
  • the n-type diffusion layer forming composition set of the present invention includes a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium, a compound containing a donor element, an alkaline earth metal, and an alkali metal.
  • a second n-type diffusion layer forming composition is containing a compound containing a donor element and a dispersion medium, a compound containing a donor element, an alkaline earth metal, and an alkali metal.
  • the n-type diffusion layer forming composition set is a combination (set) of the first n-type diffusion layer forming composition and the second n-type diffusion layer forming composition.
  • the composition can be suitably used for manufacturing a semiconductor substrate having regions having different diffusion concentrations of donor elements.
  • the details of the second n-type diffusion layer forming composition are as described above.
  • the specific compound content in the first n-type diffusion layer forming composition is not particularly limited as long as it is lower than the specific compound content in the second n-type diffusion layer forming composition.
  • the content rate of the specific compound can be, for example, 10% by mass or less in the first n-type diffusion layer forming composition, preferably 1% by mass or less, and substantially free of the specific compound. More preferred.
  • that the specific compound is not substantially contained means that the inevitable mixing of the specific compound is not prevented.
  • the ratio of the specific compound content in the second n-type diffusion layer forming composition to the specific compound content in the first n-type diffusion layer forming composition is preferably 5 or more, and preferably 10 or more. More preferably.
  • the method for producing a semiconductor substrate with an n-type diffusion layer according to the present invention comprises a step of forming a composition layer by applying the composition for forming an n-type diffusion layer according to the present invention on a semiconductor substrate, and the composition layer is formed. And subjecting the semiconductor substrate to a heat treatment.
  • the method for manufacturing a semiconductor substrate with an n-type diffusion layer may further include other steps as necessary.
  • the semiconductor substrate can be appropriately selected from commonly used semiconductor substrates according to the purpose. Of these, a silicon substrate is preferable.
  • the semiconductor substrate may be a p-type semiconductor substrate or an n-type semiconductor substrate.
  • the method for applying the n-type diffusion layer forming composition of the present invention on a semiconductor substrate is not particularly limited, and can be appropriately selected from commonly used coating methods.
  • Examples of the application method include a printing method, a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method.
  • the application amount of the n-type diffusion layer forming composition is not particularly limited.
  • the amount of the compound containing a donor element is preferably 0.01 g / m 2 to 100 g / m 2, and more preferably 0.1 g / m 2 to 10 g / m 2 .
  • the drying can be performed at a temperature of about 80 ° C. to 300 ° C.
  • the drying time can be, for example, about 1 to 10 minutes when using a hot plate, and about 10 to 30 minutes when using a dryer.
  • the drying conditions can be appropriately selected according to the solvent composition of the n-type diffusion layer forming composition, and are not particularly limited to the above conditions in the present invention.
  • the semiconductor substrate on which the composition layer is formed is heat treated.
  • the temperature of the heat treatment can be set to 600 ° C. to 1200 ° C., for example.
  • the donor element is thermally diffused into the semiconductor substrate, and an n-type diffusion layer is formed.
  • a known continuous furnace, batch furnace, or the like can be applied to the heat treatment.
  • the furnace atmosphere at the time of heat processing can also be suitably adjusted to air, oxygen, nitrogen, etc.
  • the heat treatment time can be appropriately selected according to the content of the donor element contained in the n-type diffusion layer forming composition.
  • the heat treatment time is preferably 1 minute to 60 minutes, and more preferably 2 minutes to 30 minutes.
  • a glass layer such as phosphate glass derived from a compound containing a donor element may be formed on the surface of the formed n-type diffusion layer. In that case, it is preferable to remove the glass layer by etching.
  • etching method a known method such as a method of immersing in an acid such as hydrofluoric acid or a method of immersing in an alkali such as caustic soda can be applied.
  • a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium is applied to a partial region on the semiconductor substrate. And forming the n-type diffusion layer forming composition layer on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate.
  • a metal compound (specific compound) containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in a region different from the region where the first composition layer is formed It is preferable that it is a process of providing the said n type diffused layer formation composition whose content rate is larger than said 1st n type diffused layer formation composition.
  • a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium is applied to a partial region on the semiconductor substrate.
  • the content ratio of the metal compound containing the at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in the n-type diffusion layer forming composition of the present invention in different regions is the first n.
  • a step of forming a second composition layer by applying a second n-type diffusion layer forming composition larger than the mold diffusion layer forming composition, and the first composition layer and the second composition layer include: With an n-type diffusion layer having a step of heat-treating the formed semiconductor substrate It is preferably a method for producing a conductive substrate. Thereby, a semiconductor substrate in which two or more n-type diffusion layer regions having different donor element diffusion concentrations are formed on the same surface can be produced by a simple method. Specifically, it is formed in the region where the second composition layer is formed, rather than the diffusion concentration of donor atoms in the n + -type diffusion layer formed in the region where the first composition layer is formed. The diffusion concentration of donor atoms in the n ++ type diffusion layer can be increased.
  • the second composition layer may be further formed on the first composition layer in addition to a region different from the region where the first composition layer is formed.
  • the 1st aspect in the manufacturing method of the solar cell element of this invention contains the compound and dispersion medium containing a donor element, and contains the at least 1 sort (s) of metallic element chosen from the group which consists of an alkaline-earth metal and an alkali metal.
  • the method includes forming two or more regions having different donor element diffusion concentrations on a semiconductor substrate using two or more types of n-type diffusion layer forming compositions having different metal compound contents.
  • a step of forming a first composition layer by applying a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium to a partial region on a semiconductor substrate And an alkaline earth metal and a region different from a region where the first composition layer is formed on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate.
  • Second n-type diffusion layer forming composition in which the content of the metal compound (specific compound) containing at least one metal element selected from the group consisting of alkali metals is larger than that of the first n-type diffusion layer forming composition
  • An n + -type diffusion layer is formed in the region where the second composition layer is formed, Forming n ++ type diffusion layer having a small surface sheet resistance than the n + -type diffusion layer formed product layer formed regions respectively, the n ++ type diffusion layer, forming an electrode
  • the manufacturing method of the solar cell element which has these.
  • the content ratio of the specific compound in the first n-type diffusion layer forming composition and the second n-type diffusion layer forming composition is higher in the first n-type diffusion layer forming composition than in the first n. As long as it is larger than in the mold diffusion layer forming composition, it is not particularly limited.
  • the content of the specific compound in the first n-type diffusion layer forming composition is 10% by mass or less, and the content of the specific compound in the second n-type diffusion layer forming composition is 0.01% by mass.
  • the content rate of the specific compound in said 1st n type diffused layer formation composition is 1 mass% or less, and in said 2nd n type diffused layer formation composition More preferably, the content of the specific compound is 0.01% by mass or more and 50% by mass or less, and the content of the specific compound in the first n-type diffusion layer forming composition is 0.1% by mass or less. More preferably, the content of the specific compound in the second n-type diffusion layer forming composition is 0.5% by mass or more and 30% by mass or less.
  • the diffusion concentration of the donor element in the n ++ type diffusion layer and the n + type diffusion layer formed by the manufacturing method is not particularly limited, and can be appropriately selected according to the purpose. For example, 80 [Omega / ⁇ or less the sheet resistance of 10 [Omega / ⁇ or more in the surface of the n ++ type diffusion layer, than the sheet resistance value at the surface of the sheet resistance n ++ type diffusion layer in the surface of the n + -type diffusion layer.
  • the sheet resistance value on the surface of the n ++ type diffusion layer is 10 ⁇ / ⁇ or more and less than 70 ⁇ / ⁇ , and it is preferably on the surface of the n + type diffusion layer.
  • the sheet resistance value is 70 ⁇ / ⁇ or more and 150 ⁇ / ⁇ or less
  • the sheet resistance value on the surface of the n ++ type diffusion layer is 30 ⁇ / ⁇ or more and 60 ⁇ / ⁇ or less
  • the sheet resistance value is 80 ⁇ / ⁇ or more and 120 ⁇ / ⁇ or less.
  • the sheet resistance value on the surface of the semiconductor substrate is measured by a commonly used four-point probe method. The four-probe method can be performed using, for example, a Loresta-EP MCP-T360 type low resistivity meter manufactured by Mitsubishi Chemical Corporation.
  • the shapes of the first and second composition layers formed by applying the first and second n-type diffusion layer forming compositions on the semiconductor substrate are not particularly limited and are appropriately selected according to the purpose. Is done.
  • the first composition layer is formed in a region corresponding to the region where the electrode is formed, and the second composition layer is formed at least in a region other than the region where the electrode is formed.
  • the second composition layer is formed on the entire surface of the semiconductor substrate including the region where the first composition layer is formed. It may be formed.
  • the solar cell element which has a selective emitter structure can be efficiently manufactured by forming the 1st and 2nd composition layer.
  • an electrode is formed on the n ++ type diffusion layer formed by thermal diffusion treatment.
  • the electrode formation method is not particularly limited, and can be appropriately selected from commonly used electrode formation methods. For example, an electrode forming method using a commercially available silver paste can be applied.
  • the method for manufacturing the solar cell element further includes a step of forming an electrode on the p-type diffusion layer on the semiconductor substrate.
  • the method for forming the electrode on the p-type diffusion layer is not particularly limited, and can be appropriately selected from commonly used electrode forming methods. For example, an electrode forming method using a commercially available aluminum paste can be applied.
  • the second aspect of the method for producing a solar cell element of the present invention is a metal containing at least one metal element selected from the group consisting of a compound containing a donor element, an alkaline earth metal, and an alkali metal on a semiconductor substrate.
  • a step of forming an n-type diffusion layer forming composition layer by applying at least one kind of an n-type diffusion layer forming composition containing a compound and a dispersion medium, and the n-type diffusion layer forming composition layer was formed
  • a method for manufacturing a solar cell element comprising: a step of forming a n-type diffusion layer by performing a heat treatment on a semiconductor substrate; and a step of forming an electrode on the formed n-type diffusion layer.
  • the manufacturing method of the second aspect includes an acceptor element on the same surface as the surface on which the n-type diffusion layer forming composition layer is formed on the semiconductor substrate before the step of forming the n-type diffusion layer. It is preferable to further include a step of forming a p-type diffusion layer forming composition layer by applying a p-type diffusion layer forming composition containing a compound and a dispersion medium. Thereby, for example, a back contact type solar cell element can be efficiently manufactured.
  • the solar cell element manufactured by the method for manufacturing a solar cell element is used for manufacturing a solar cell.
  • the solar cell includes at least one type of solar cell element manufactured by the above manufacturing method, and is configured by arranging a wiring material (such as a tab wire) on the electrode of the solar cell element.
  • the solar cell may be constituted by connecting a plurality of solar cell elements via a wiring material and further sealing with a sealing material.
  • the wiring material and the sealing material are not particularly limited, and can be appropriately selected from those usually used in the industry. There is no particular limitation on the shape and size of the solar cell. For example, it is preferably 0.5 m 2 to 3 m 2 .
  • FIG. 1 is a schematic cross-sectional view conceptually showing an example of the manufacturing process of the solar cell element according to the present embodiment.
  • common constituent elements are denoted by the same reference numerals.
  • the size of each component shown in the drawings is an example, and does not limit the relative size relationship between the components.
  • an alkaline solution is applied to a crystalline silicon substrate which is a p-type semiconductor substrate 10 to remove a damaged layer, and a texture structure (the description of the texture structure is omitted in the figure) is obtained by etching.
  • a texture structure (the description of the texture structure is omitted in the figure) is obtained by etching.
  • the damaged layer on the silicon surface generated when slicing from the ingot is removed with 20% by mass caustic soda.
  • etching is performed with a mixed solution of 1% by mass caustic soda and 10% by mass isopropyl alcohol to form a texture structure.
  • front surface the light confinement effect is promoted and high efficiency is achieved.
  • the first composition layer 11 is formed by applying the first n-type diffusion layer forming composition to the surface that becomes the light receiving surface of the p-type semiconductor substrate 10.
  • the application method include a printing method, a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method.
  • the amount of glass powder is preferably 0.01 g / m 2 to 100 g / m 2, and more preferably 0.1 g / m 2 to 10 g / m 2 .
  • drying can be performed at a temperature of about 80 ° C. to 300 ° C.
  • the drying time can be about 1 to 10 minutes when using a hot plate or the like, and about 10 to 30 minutes when using a dryer or the like.
  • the drying conditions depend on the solvent composition of the n-type diffusion layer forming composition, and are not particularly limited to the above conditions in the present invention.
  • a second n-type diffusion layer forming composition is applied to the entire light receiving surface including the first composition layer 11 to form the second composition layer 12.
  • the concentration of the metal compound (specific compound) containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals contained in the second n-type diffusion layer forming composition is It is relatively higher than the concentration of the specific compound contained in one n-type diffusion layer forming composition.
  • the first n-type diffusion layer forming composition containing 10% by mass or less, preferably not containing the specific compound is applied.
  • a second n-type diffusion layer forming composition containing 0.01% to 50% by weight of the specific compound on the entire light-receiving surface and having a higher concentration of the specific compound than the first n-type diffusion layer forming composition It is preferable to give.
  • the second composition layer 12 is formed in the region of the light receiving surface other than the first composition layer. May be.
  • the semiconductor substrate 10 on which the first composition layer 11 and the second composition layer 12 are formed is heat-treated.
  • the temperature of the heat treatment is not particularly limited, but is preferably 600 ° C. to 1200 ° C., more preferably 750 ° C. to 1050 ° C.
  • the heat treatment time is not particularly limited. For example, it is preferably performed for 1 to 30 minutes.
  • the donor element diffuses into the semiconductor substrate as shown in FIG. 1 (3), and an n ++ type diffusion layer 13 and an n + type diffusion layer 14 are formed.
  • a known continuous furnace, batch furnace, or the like can be applied to the heat treatment.
  • the furnace atmosphere at the time of heat processing can also be suitably adjusted to air, oxygen, nitrogen, etc.
  • the heat treatment time can be appropriately selected according to the content of the donor element contained in the first and second n-type diffusion layer forming compositions. For example, it can be 1 minute to 60 minutes, more preferably 2 minutes to 30 minutes.
  • the n + -type diffusion layer 14 formed by the second n-type diffusion layer forming composition containing a large amount of a metal compound containing at least a metal element selected from the group consisting of alkaline earth metals and alkali metals.
  • n ++ type diffusion layer 13 and the n + type diffusion layer 14 are formed using the first and second n-type diffusion layer forming compositions, as described above, two or more kinds having different diffusion concentrations of the donor element are used. Since the n-type diffusion layer is selectively formed in a desired region by a simple method, a solar cell element having a selective emitter structure can be manufactured efficiently.
  • the heat-treated product layer 11A of the first n-type diffusion layer forming composition is formed on the surface of the n ++ -type diffusion layer 13 formed by the heat treatment, and the second n-type diffusion layer is formed on the surface of the n + -type diffusion layer 14.
  • a heat treatment product layer 12A of the composition is formed. Since a glass layer such as phosphate glass is formed in these heat-treated layers, the phosphate glass is removed by an etching process.
  • a known method such as a method of immersing in an acid such as hydrofluoric acid or a method of immersing in an alkali such as caustic soda can be applied.
  • etching two types of n-type diffusion layers, n ++ -type diffusion layer 13 and n + -type diffusion layer 14 having different donor element diffusion concentrations, can be easily formed as shown in FIG.
  • the first and second n-type diffusion layer forming compositions two types of n-type diffusion layers having different donor element diffusion concentrations can be easily formed by a single heat treatment.
  • two types of n-type diffusion layers with different donor element diffusion concentrations were formed.
  • three or more types of n-type diffusion layer forming compositions with different specific compound contents were prepared and selected. In particular, by providing the desired region, it is possible to easily form three or more types of n-type diffusion layers having different donor element diffusion concentrations.
  • the antireflection film 15 is formed by applying a known technique.
  • the antireflection film 15 is a silicon nitride film, it is formed by a plasma CVD method using a mixed gas of SiH 4 and NH 3 as a raw material. At this time, hydrogen diffuses into the crystal, and orbits that do not contribute to the bonding of silicon atoms, that is, dangling bonds and hydrogen are combined to inactivate defects (hydrogen passivation).
  • the flow rate ratio NH 3 / SiH 4 of the mixed gas is 0.05 to 1.0
  • the pressure in the reaction chamber is 0.1 Torr (13.3 Pa) to 2 Torr (266.6 Pa)
  • the film is formed under the conditions of a temperature of 300 ° C. to 550 ° C. and a frequency for plasma discharge of 100 kHz or more.
  • the thickness of the antireflection film is preferably 10 nm to 300 nm, and more preferably 30 nm to 150 nm.
  • a surface electrode metal paste is applied by screen printing or the like on the antireflection film 15 formed on the n ++ type diffusion layer 13 region of the light receiving surface and dried. Then, the surface electrode metal paste layer 16A is formed.
  • the metal paste for a surface electrode includes (1) metal particles and (2) glass particles as essential components, and includes (3) a resin binder, (4) other additives, and the like as necessary.
  • a back electrode metal paste layer 17A is formed on the back side.
  • the material and forming method of the back electrode 17 are not particularly limited.
  • the back electrode metal paste layer 17 ⁇ / b> A may be formed by applying a metal paste for the back electrode including a metal such as aluminum, silver, or copper and drying the paste.
  • a back electrode metal paste layer 17A is formed using a back electrode metal paste containing aluminum, and this is fired to form the back electrode 17, and at the same time, a p + -type diffusion layer (high Concentration electric field layer) 18 is formed.
  • a silver electrode forming silver paste may be provided on a part of the rear surface for connection between solar cell elements in the module process.
  • the manufacturing method of the p + -type diffusion layer (high concentration electric field layer) 18 on the back surface is not limited to the method using the metal paste for the back electrode containing aluminum, and any conventionally known method is used. Can be adopted, and the choice of manufacturing method is expanded.
  • the p + -type diffusion layer 18 can be formed by applying a p-type diffusion layer forming composition containing a Group 13 element such as B (boron).
  • the thickness of the front surface electrode 17 on the back surface can be made thinner than the conventional one.
  • the semiconductor substrate on which the front electrode metal paste layer 16A and the back electrode metal paste layer 17A are formed is baked to form the front electrode 16 and the back electrode 17 as shown in FIG. To complete.
  • the baking treatment can be performed in the range of 600 ° C. to 900 ° C. for several seconds to several minutes.
  • the antireflection film 15 that is an insulating film is melted by the glass particles contained in the metal paste layer 16A for the surface electrode, and the surface of the p-type semiconductor substrate 10 is also partially melted, so that the metal particles ( For example, silver particles) form a contact portion with the n ++ type diffusion layer 13 of the p-type semiconductor substrate 10 and solidify.
  • the surface electrode 16 and the p-type semiconductor substrate 10 are electrically connected. This is called fire-through.
  • the back electrode metal paste layer 17A containing aluminum is formed on the back surface side, when the back electrode 17 is formed, a p + type diffusion layer 18 in which aluminum diffuses into the p type semiconductor substrate 10 is formed.
  • the back surface field effect called Back Surface Field appears and contributes to high efficiency.
  • FIGS. 2A and 2B the surface electrode 16 includes a bus bar electrode 30 and finger electrodes 32 intersecting with the bus bar electrode 30.
  • FIG. 2A is a plan view of a solar cell element in which the surface electrode 16 includes a bus bar electrode 30 and a finger electrode 32 intersecting the bus bar electrode 30 as viewed from the light receiving surface (front surface).
  • FIG. 2B is an enlarged perspective view showing a part of FIG.
  • Such a surface electrode 16 can be formed, for example, by applying a metal paste by screen printing or the like as described above and baking it. Further, it can be formed by means such as plating of electrode material, vapor deposition of electrode material by electron beam heating in high vacuum.
  • the surface electrode 16 composed of the bus bar electrode 30 and the finger electrode 32 is generally used as an electrode on the light receiving surface side and is well known, and known forming means for the bus bar electrode and finger electrode on the light receiving surface side can be applied. it can.
  • the n ++ type diffusion layer 13 and the n + type diffusion layer 14 are formed on the front surface
  • the p + type diffusion layer 18 is formed on the back surface
  • the surface is further formed on the n ++ type diffusion layer 13 and the p + type diffusion layer 18, respectively.
  • the solar cell element provided with the electrode 16 and the back electrode 17 has been described.
  • a back contact solar cell element can be easily produced.
  • the back contact type solar cell element has all electrodes provided on the back surface to increase the area of the light receiving surface.
  • n-type diffusion layer forming composition of the present invention can form an n + -type diffusion layer portion only at a specific portion, and thus can be suitably applied to the production of a back contact type solar cell element. .
  • an n type diffusion layer forming composition containing a donor element such as phosphorus and a p type diffusion layer forming composition containing an acceptor element such as boron An n + -type diffusion layer region and a p + -type diffusion layer region can be formed by applying an object to each desired region and performing heat treatment.
  • the n-type diffusion layer forming composition of the present invention can adjust the diffusibility of the donor element by containing the specific compound, the diffusion concentration of the n-type diffusion layer forming composition into the semiconductor substrate can be adjusted. it can. Thereby, the n + -type diffusion layer portion and the p + -type diffusion layer portion can be formed at the same time, and the process time can be shortened.
  • a back contact solar cell element can be manufactured by a manufacturing method including a manufacturing process as schematically shown in FIG.
  • a texture structure (the description of the texture structure is omitted in FIG. 3) is formed on the light receiving surface (front surface) of the n-type semiconductor substrate 10A, and the back surface is a low defect structure such as a mirror shape.
  • the n-type semiconductor substrate is immersed in a mixed acid containing nitric acid, hydrofluoric acid, acetic acid, and the like to remove defects.
  • a texture structure is formed only on the light receiving surface by a technique such as alkali etching or plasma etching.
  • a technique such as alkali etching or plasma etching.
  • the n-type diffusion layer forming composition and the p-type diffusion layer forming composition of the present invention are partially applied to the back surface of the n-type semiconductor substrate 10A and dried, as shown in FIG.
  • the n-type diffusion layer forming composition layer 12 and the p-type diffusion layer forming composition layer 19 are formed respectively.
  • the p-type diffusion layer forming composition include a composition containing a compound (preferably in the form of glass particles) containing a Group 13 element such as B (boron) and a dispersion medium.
  • B boron
  • a printing method there are a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method.
  • a drying method there is no restriction
  • the p + -type diffusion layer 18 and the n + -type diffusion layer 14 become as shown in FIG. As shown in (3), each is formed in a specific region.
  • heat treatment is preferably performed so that the surface sheet resistance value of the p + -type diffusion layer is 30 ⁇ / ⁇ to 140 ⁇ / ⁇ , and the surface sheet resistance value of the n + -type diffusion layer is 30 ⁇ / ⁇ to 100 ⁇ / ⁇ .
  • the n-type diffusion layer forming composition contains a specific compound and the diffusion capacity of the donor element is controlled, the p + -type diffusion layer and the n + -type diffusion layer can be formed at the same time, thus simplifying the manufacturing process. it can.
  • the atmosphere in the furnace during the heat treatment can be appropriately adjusted to air, oxygen, nitrogen, or the like.
  • a glass layer such as a phosphate glass layer is formed on the formed n + -type diffusion layer as the heat-treated product layer 12A of the n-type diffusion layer forming composition.
  • a glass layer such as a borosilicate glass layer is formed as the heat-treated product layer 19A of the p-type diffusion layer forming composition.
  • an antireflection film 15 is formed on the light receiving surface, and a passivation film 20 is formed on the back surface.
  • the antireflection film 15 is formed by applying a known technique.
  • the antireflection film 15 is a silicon nitride film, it is formed by a plasma CVD method using a mixed gas of SiH 4 and NH 3 as a raw material. At this time, hydrogen diffuses into the crystal, and orbits that do not contribute to the bonding of silicon atoms, that is, dangling bonds and hydrogen are combined to inactivate defects (hydrogen passivation).
  • the flow rate ratio NH 3 / SiH 4 of the mixed gas is 0.05 to 1.0
  • the pressure in the reaction chamber is 0.1 Torr (13.3 Pa) to 2 Torr (266.6 Pa)
  • the film is formed under the conditions of a temperature of 300 ° C. to 550 ° C. and a frequency for plasma discharge of 100 kHz or more.
  • the passivation film on the back surface may be a silicon nitride film as in the case of the light receiving surface, but a silicon oxide (SiO 2 ) film, an amorphous silicon film, or the like may be formed by a CVD method or the like.
  • the antireflection film and the passivation film may each have a two-layer structure made of a silicon oxide (SiO 2 ) film, a silicon nitride film, or the like.
  • an electrode is formed on each of the n + type diffusion layer and the p + type diffusion layer formed on the semiconductor substrate.
  • the electrode is formed, for example, by forming an electrode forming metal paste layer 17A containing glass powder having fire-through properties on the passivation film 20. Next, by baking this, a back electrode 17 penetrating the passivation film 20 can be formed as shown in FIG.
  • the composition of the electrode forming metal paste is not particularly limited. What contains metals, such as aluminum, silver, copper, and the glass powder which has fire through property, can be used.
  • Example 1> (Preparation of n-type diffusion layer forming composition) A solution of terpineol (manufactured by Nippon Terpene Chemical Co., Ltd., Terpineol-LW) containing 3.8% by mass of ethyl cellulose (manufactured by Dow Chemical Co., Ltd., Etcelle “STD200”) was prepared. 9 g of this solution and 1 g of diphosphorus pentoxide as a compound containing a donor element were mixed in a mortar to obtain a paste.
  • terpineol manufactured by Nippon Terpene Chemical Co., Ltd., Terpineol-LW
  • ethyl cellulose manufactured by Dow Chemical Co., Ltd., Etcelle “STD200”
  • 0.1 g of magnesium oxide (manufactured by Wako Pure Chemical Industries, volume average particle size 0.2 ⁇ m, substantially spherical) is added to 10 g of this paste and mixed in a mortar to obtain n as a second n-type diffusion layer forming composition.
  • a mold diffusion layer forming composition was prepared.
  • n ++ type diffusion layer forming composition ⁇ for evaluation
  • a solution of terpineol (manufactured by Nippon Terpene Chemical Co., Ltd., Terpineol-LW) containing 3.8% of ethyl cellulose (manufactured by Dow Chemical Co., Ltd., Etcelle “STD200”) was prepared.
  • 9 g of this solution and 1 g of diphosphorus pentoxide (manufactured by High-Purity Chemical Laboratory) as a compound containing a donor element are mixed in a mortar to form an n ++- type diffusion layer as a first n-type diffusion layer forming composition.
  • Composition ⁇ was prepared.
  • an n ++ -type diffusion layer forming composition ⁇ is partially applied by screen printing on a hot plate at 150 ° C. And dried for 1 minute to form a first composition layer. Subsequently, the n-type diffusion layer forming composition obtained by the preparation of the n-type diffusion layer forming composition is applied to the entire surface including the first composition layer on the surface of the p-type silicon substrate, and a hot plate at 150 ° C. A second composition layer was formed by drying for 1 minute. Air is 5 L / min.
  • Thermal diffusion treatment was performed for 10 minutes in a tunnel furnace (horizontal tube diffusion furnace ACCURON CQ-1200, manufactured by Kokusai Electric) at 950 ° C., which was flowed in Thereafter, in order to remove the glass layer formed on the surface of the p-type silicon substrate, the substrate is immersed in an aqueous 2.5% by mass HF solution for 5 minutes, and then washed with running water, ultrasonically washed, and dried, and n ++ A p-type silicon substrate on which a type diffusion layer and an n + type diffusion layer were formed was obtained.
  • a tunnel furnace horizontal tube diffusion furnace ACCURON CQ-1200, manufactured by Kokusai Electric
  • n + -type diffusion layer and the n ++ type diffusion layer is formed on the p-type silicon substrate
  • Ag electrode paste at the top of the region n ++ diffusion layer is formed of a light-receiving surface of the imparted by screen printing, including Ag
  • An electrode forming composition layer was formed.
  • An Al electrode paste was screen-printed on the entire back surface to form an electrode-forming composition layer containing Al.
  • firing was performed at a first zone: 400 ° C., a second zone: 850 ° C., and a third zone: 650 ° C. with a tact time of 10 seconds, and then the edge was cut to obtain a solar cell element.
  • the obtained solar cell element was evaluated for IV characteristics using a solar cell evaluation system (NF circuit design block, As-510-PV), the conversion efficiency was 9.2%.
  • the powder X-ray diffraction (XRD) pattern of the obtained glass particles was measured with an X-ray diffractometer (RINT-2000, manufactured by Rigaku Corp.) using Cu—K ⁇ ray using a Ni filter, it was amorphous. It was confirmed that there was.
  • the particle diameter of the obtained glass particles was substantially spherical, and the volume average particle diameter was measured by a laser diffraction particle size distribution measuring device to be 8 ⁇ m.
  • the volume average particle diameter was calculated based on the Mie scattering theory by detecting the relationship between the scattered light intensity and the angle of the laser light applied to the particles.
  • a sample obtained by dispersing 0.1 g of a sample in 10 g of terpineol as a dispersion medium was used as a measurement sample.
  • the wavelength of the laser beam was 750 nm.
  • the glass particle shape was determined by observation using a TM-1000 scanning electron microscope manufactured by Hitachi High-Technologies Corporation.
  • a terpineol solution containing 3.8% ethyl cellulose was prepared. 9 g of this solution and 1 g of the glass particles obtained above as a compound containing a donor element were mixed in a mortar to obtain a paste. Next, 0.1 g of magnesium oxide (manufactured by Wako Pure Chemical Industries, volume average particle size 0.2 ⁇ m, substantially spherical) is added to 10 g of this paste and mixed, and the n-type diffusion layer forming composition of Example 2 is used as an n-type. A diffusion layer forming composition was prepared.
  • n ++ type diffusion layer forming composition ⁇ A terpineol solution containing 3.8% ethylcellulose was prepared. 9 g of this solution and 1 g of the glass powder obtained above as a compound containing a donor element were mixed in a mortar to prepare an n ++ type diffusion layer forming composition ⁇ as a first n type diffusion layer forming composition. .
  • Example 2 I evaluated n-type diffusion layer-forming composition of Example 2 I did it.
  • Examples 3 to 10 Comparative Examples 1 to 3> (Preparation of n-type diffusion layer forming composition)
  • the n-type diffusion layers of Examples 3 to 10 and Comparative Examples 1 to 3 were the same as Example 2 except that the materials used for the preparation of the n-type diffusion layer forming composition were changed as shown in Table 1.
  • a forming composition was prepared.
  • the numerical values in Table 1 indicate the blending amount (g), and “-” indicates that the blending is not performed.
  • an n-type diffusion layer could be formed in a specific region. Further, by using the n-type diffusion layer forming compositions of Examples 1 to 10 and the n ++ type diffusion layer forming composition ⁇ or ⁇ , diffusion layers having different diffusion concentrations can be formed by a single thermal diffusion treatment. did it. Further, the sheet resistance value of Example 4 in which the compounding amount of calcium hydroxide is 1 g is 95 ⁇ , the sheet resistance value of Example 4 in which the compounding amount of calcium hydroxide is 0.5 g is 85 ⁇ , and the compounding amount of calcium hydroxide. The sheet resistance value of Example 4 in which is 0.01 g was 40 ⁇ .
  • the n-type diffusion layer forming composition of the present invention adjusts the blending amount of the metal compound (specific compound) containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals. This shows that the diffusion concentration can be easily adjusted. In addition, the conversion efficiency of the solar cell elements prepared using the n-type diffusion layer forming compositions of Examples 1 to 10 was good.
  • the region to which the first n-type diffusion layer forming composition is applied and the second n-type diffusion layer forming composition A clear difference was not recognized in the surface sheet resistance value of the region to which the product was applied. That is, it can be seen that the n-type diffusion layer forming composition not containing an alkaline earth metal or a metal compound having an alkali metal does not have an effect of adjusting the diffusion concentration. Further, the conversion efficiency of the solar cell elements prepared using the n-type diffusion layers of Comparative Examples 1 to 3 was low.
  • Comparative Example 2 it is considered that the effect of adjusting the diffusion concentration could not be obtained because polyethyleneimine was decomposed at a high temperature (in this case, 950 ° C.) subjected to thermal diffusion treatment.
  • Comparative Example 3 it is considered that the iron element diffused in the substrate becomes a recombination center of carriers (electrons and holes) in the semiconductor substrate, and the conversion efficiency is lowered because the lifetime of the carriers is shortened.
  • an n-type diffusion layer can be formed in a specific region, and the diffusion concentration of the donor element in the formed n-type diffusion layer can be easily achieved. It can be seen that it is possible to adjust to.

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Abstract

The present invention provides an n-type diffusion layer forming composition containing: a compound including a donor element; a metal compound being a compound different from the compound including the donor element, and containing at least one type of metal element selected from a group comprising an alkaline earth metal and an alkaline metal; and a dispersion medium. Also provided is a production method for a semiconductor substrate having an n-type diffusion layer, whereby the n-type diffusion layer forming composition is applied upon the semiconductor substrate and a composition layer is formed, and the semiconductor substrate having the composition layer formed thereon is heat treated.

Description

ｎ型拡散層形成組成物、ｎ型拡散層形成組成物セット、ｎ型拡散層付き半導体基板の製造方法、及び太陽電池素子の製造方法N-type diffusion layer forming composition, n-type diffusion layer forming composition set, method for manufacturing semiconductor substrate with n-type diffusion layer, and method for manufacturing solar cell element
　本発明は、ｎ型拡散層形成組成物、ｎ型拡散層形成組成物セット、ｎ型拡散層付き半導体基板の製造方法、及び太陽電池素子の製造方法に関する。 The present invention relates to an n-type diffusion layer forming composition, an n-type diffusion layer forming composition set, a method for manufacturing a semiconductor substrate with an n-type diffusion layer, and a method for manufacturing a solar cell element.
　従来のシリコン太陽電池素子（太陽電池セル）の製造工程について説明する。
　まず、光閉じ込め効果を促して高効率化を図るよう、受光面にテクスチャ構造を形成したｐ型シリコン基板を準備し、続いてオキシ塩化リン（ＰＯＣｌ３）、窒素、及び酸素の混合ガス雰囲気において８００℃～９００℃で数十分の処理を行って一様にｎ型拡散層を形成する。この従来の方法では、混合ガスを用いてリンの拡散を行うため、表面のみならず、側面及び裏面にもｎ型拡散層が形成される。そのため、側面のｎ型拡散層を除去するためのサイドエッチング工程が必要であった。また、裏面のｎ型拡散層はｐ＋型拡散層へ変換する必要がある。そのため裏面のｎ型拡散層の上に第１３族元素であるアルミニウムを含むアルミニウムペーストを付与した後、熱処理して、アルミニウムの拡散によってｎ型拡散層からｐ＋型拡散層に変換するのと同時に、オーミックコンタクトを得ていた。 The manufacturing process of the conventional silicon solar cell element (solar cell) will be described.
First, a p-type silicon substrate having a textured structure formed on the light receiving surface is prepared so as to promote the light confinement effect, and then in a mixed gas atmosphere of phosphorus oxychloride (POCl 3 ), nitrogen, and oxygen. An n-type diffusion layer is uniformly formed by performing several tens of minutes at 800 ° C. to 900 ° C. In this conventional method, since phosphorus is diffused using a mixed gas, n-type diffusion layers are formed not only on the surface but also on the side surface and the back surface. Therefore, a side etching process for removing the side n-type diffusion layer is necessary. Further, the n-type diffusion layer on the back surface needs to be converted into a p + -type diffusion layer. Therefore, after applying an aluminum paste containing aluminum as a group 13 element on the n-type diffusion layer on the back surface, heat treatment is performed, and at the same time the n-type diffusion layer is converted to the p + -type diffusion layer by the diffusion of aluminum. , Got ohmic contact.
　上記に関連して、ドナー元素を含むガラス粉末と分散媒とを含有するｎ型拡散層形成組成物を半導体基板に塗布し、熱拡散処理を行なうことにより、半導体基板の側面又は裏面に不要なｎ型拡散層を形成させることなく、特定の領域にｎ型拡散層を形成する太陽電池素子の製造方法が提案されている（例えば、国際公開２０１１／０９０２１６号パンフレット参照）。 In relation to the above, an n-type diffusion layer forming composition containing a glass powder containing a donor element and a dispersion medium is applied to a semiconductor substrate and subjected to thermal diffusion treatment, so that it is unnecessary on the side surface or back surface of the semiconductor substrate. A method for manufacturing a solar cell element in which an n-type diffusion layer is formed in a specific region without forming an n-type diffusion layer has been proposed (see, for example, International Publication No. 2011/090216 pamphlet).
　一方、変換効率を高めることを目的とした太陽電池素子の構造として、電極直下の領域のドナー元素の拡散濃度（以下、単に「拡散濃度」ともいう）に比べて、電極直下以外の領域における拡散濃度を低くした選択エミッタ構造が知られている（例えば、L.Debarge, M.Schott, J.C.Muller, R.Monna、Solar Energy Materials & Solar Cells 74 (2002) 71-75.参照）。この構造では、電極直下に拡散濃度が高い領域（以下、この領域を「選択エミッタ」ともいう）が形成されているため、電極とシリコンとの接触抵抗を低減できる。さらに電極が形成された領域以外では拡散濃度が相対的に低くなっているため、太陽電池素子の変換効率を向上することができる。 On the other hand, as a structure of a solar cell element for the purpose of increasing the conversion efficiency, the diffusion in the region other than directly under the electrode is compared with the diffusion concentration of the donor element in the region directly under the electrode (hereinafter also simply referred to as “diffusion concentration”). A selective emitter structure with a low concentration is known (see, for example, L. Debarge, M. Schott, JCMuller, R.Monna, Solar Energy Materials and Solar Cells 74 (2002) 71-75). In this structure, a region having a high diffusion concentration immediately below the electrode (hereinafter, this region is also referred to as “selective emitter”) is formed, so that the contact resistance between the electrode and silicon can be reduced. Furthermore, since the diffusion concentration is relatively low except in the region where the electrode is formed, the conversion efficiency of the solar cell element can be improved.
　しかしながら、従来のｎ型拡散層の形成方法を用いて選択エミッタ構造を形成するためには、複数回の熱拡散処理とマスキングによる部分エッチング等とを組み合わせた複雑な工程が必要であった。 However, in order to form the selective emitter structure using the conventional method for forming the n-type diffusion layer, a complicated process combining a plurality of thermal diffusion processes and partial etching by masking is required.
　本発明は、以上の従来の問題点に鑑みなされたものであり、特定の領域にｎ型拡散層を形成することができ、かつ、形成されるｎ型拡散層におけるドナー元素の拡散濃度を容易に調節することを可能にするｎ型拡散層形成組成物、これを用いたｎ型拡散層付き半導体基板の製造方法及び太陽電池素子の製造方法の提供を課題とする。 The present invention has been made in view of the above-described conventional problems, and an n-type diffusion layer can be formed in a specific region, and the diffusion concentration of a donor element in the formed n-type diffusion layer can be easily achieved. It is an object of the present invention to provide an n-type diffusion layer forming composition that can be adjusted to the above, a method for manufacturing a semiconductor substrate with an n-type diffusion layer using the composition, and a method for manufacturing a solar cell element.
　前記課題を解決するための具体的手段は以下の通りである。
＜１＞　ドナー元素を含む化合物と、前記ドナー元素を含む化合物とは異なる化合物であり、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物と、分散媒と、を含有するｎ型拡散層形成組成物である。 Specific means for solving the above problems are as follows.
<1> A compound containing a donor element is different from the compound containing a donor element, and a metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal, and a dispersion And an n-type diffusion layer forming composition containing the medium.
＜２＞　前記ドナー元素を含む化合物は、Ｐ（リン）を含有する化合物である前記＜１＞に記載のｎ型拡散層形成組成物である。 <2> The compound containing the donor element is the n-type diffusion layer forming composition according to <1>, which is a compound containing P (phosphorus).
＜３＞　前記金属化合物は、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選ばれる少なくとも１種の金属元素を含有する化合物である前記＜１＞又は＜２＞に記載のｎ型拡散層形成組成物である。 <3> The metal compound is a compound containing at least one metal element selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium <1 > Or <2>. The n-type diffusion layer forming composition.
＜４＞　前記金属化合物の含有率が、０．０１質量％以上５０質量％以下である前記＜１＞～＜３＞のいずれか１項に記載のｎ型拡散層形成組成物である。 <4> The n-type diffusion layer forming composition according to any one of <1> to <3>, wherein the content of the metal compound is 0.01% by mass or more and 50% by mass or less.
＜５＞　前記金属化合物は、常温で固体の粒子であり、前記粒子の体積平均粒子径が、０．０１μｍ以上３０μｍ以下である前記＜１＞～＜４＞のいずれか１項に記載のｎ型拡散層形成組成物である。 <5> The metal compound is a solid particle at normal temperature, and the volume average particle diameter of the particle is 0.01 μm or more and 30 μm or less. This is a mold diffusion layer forming composition.
＜６＞　前記ドナー元素を含む化合物は、Ｐ２Ｏ３及びＰ２Ｏ５からなる群より選ばれる少なくとも１種を含有する化合物である前記＜１＞～＜５＞のいずれか１項に記載のｎ型拡散層形成組成物である。 <6> The compound according to any one of <1> to <5>, wherein the compound containing the donor element is a compound containing at least one selected from the group consisting of P 2 O 3 and P 2 O 5. The n-type diffusion layer forming composition.
＜７＞　前記ドナー元素を含む化合物は、ガラス粒子の形態である前記＜１＞～＜６＞のいずれか１項に記載のｎ型拡散層形成組成物である。 <7> The compound containing a donor element is the n-type diffusion layer forming composition according to any one of <1> to <6>, which is in the form of glass particles.
＜８＞　前記ガラス粒子が、Ｐ２Ｏ３及びＰ２Ｏ５からなる群より選択される少なくとも１種のドナー元素含有物質と、ＳｉＯ２、Ｋ２Ｏ、Ｎａ２Ｏ、Ｌｉ２Ｏ、ＢａＯ、ＳｒＯ、ＣａＯ、ＭｇＯ、ＢｅＯ、ＺｎＯ、ＰｂＯ、ＣｄＯ、Ｖ２Ｏ５、ＳｎＯ、ＺｒＯ２及びＭｏＯ３からなる群より選択される少なくとも１種のガラス成分物質と、を含有する前記＜７＞に記載のｎ型拡散層形成組成物である。 <8> At least one donor element-containing material selected from the group consisting of P 2 O 3 and P 2 O 5 , SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO. <7> containing at least one glass component material selected from the group consisting of SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V 2 O 5 , SnO, ZrO 2 and MoO 3 Is an n-type diffusion layer forming composition.
＜９＞　前記ガラス粒子の含有率が、１質量％以上８０質量％以下である前記＜７＞又は＜８＞に記載のｎ型拡散層形成組成物である。 <9> The n-type diffusion layer forming composition according to <7> or <8>, wherein the glass particle content is 1% by mass or more and 80% by mass or less.
＜１０＞　前記ガラス粒子中のＰ２Ｏ３及びＰ２Ｏ５の総含有率が０．０１質量％以上１０質量％以下である前記＜７＞～＜９＞のいずれか１項に記載のｎ型拡散層形成組成物である。 <10> The content according to any one of <7> to <9>, wherein the total content of P 2 O 3 and P 2 O 5 in the glass particles is 0.01% by mass or more and 10% by mass or less. It is an n-type diffusion layer forming composition.
＜１１＞　有機バインダをさらに含有する前記＜１＞～＜１０＞のいずれか１項に記載のｎ型拡散層形成組成物である。 <11> The n-type diffusion layer forming composition according to any one of <1> to <10>, further including an organic binder.
＜１２＞　半導体基板上の全面又は一部に、前記＜１＞～＜１１＞のいずれか１項に記載のｎ型拡散層形成組成物を付与して組成物層を形成する工程と、前記組成物層が形成された半導体基板に熱処理を施す工程とを有するｎ型拡散層付き半導体基板の製造方法である。 <12> A step of forming a composition layer by applying the n-type diffusion layer forming composition according to any one of <1> to <11> to the entire surface or a part of a semiconductor substrate; And a step of performing a heat treatment on the semiconductor substrate on which the composition layer is formed.
＜１３＞　半導体基板上の一部の領域に、ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物を付与して第一の組成物層を形成する工程を更に有し、前記ｎ型拡散層形成組成物層を形成する工程は、前記半導体基板上の前記第一の組成物層が形成される面と同一の面上であり、前記第一の組成物層が形成される領域とは異なる領域に、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が前記第一のｎ型拡散層形成組成物よりも大きい前記ｎ型拡散層形成組成物を付与する工程である前記＜１２＞に記載のｎ型拡散層付き半導体基板の製造方法である。 <13> A step of forming a first composition layer by applying a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium to a partial region on a semiconductor substrate. And the step of forming the n-type diffusion layer forming composition layer is on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate, and the first composition layer The first n-type diffusion layer forming composition has a content of a metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in a region different from the region where the first n-type diffusion layer is formed. It is a manufacturing method of the semiconductor substrate with an n-type diffused layer as described in said <12> which is a process of providing the said n-type diffused layer formation composition larger than this.
＜１４＞　半導体基板上の一部の領域に、ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物を付与して第一の組成物層を形成する工程と、前記半導体基板上の前記第一の組成物層が形成される面と同一の面上であり、前記第一の組成物層が形成される領域とは異なる領域に、前記＜１＞～＜１１＞のいずれか１項に記載のｎ型拡散層形成組成物であり、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が前記第一のｎ型拡散層形成組成物よりも大きい第二のｎ型拡散層形成組成物を付与して第二の組成物層を形成する工程と、前記第一の組成物層及び第二の組成物層が形成された前記半導体基板に熱拡散処理を施して、前記半導体基板上の前記第二の組成物層が形成された領域にｎ＋型拡散層を、前記第一の組成物層が形成された領域に前記ｎ＋型拡散層よりも小さい表面シート抵抗値を有するｎ＋＋型拡散層をそれぞれ形成する工程と、前記ｎ＋＋型拡散層上に、電極を形成する工程とを有する太陽電池素子の製造方法である。 <14> forming a first composition layer by applying a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium to a partial region on a semiconductor substrate; <1> to <11 in a region different from a region where the first composition layer is formed on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate. > The n-type diffusion layer forming composition according to any one of the above, wherein the content of the metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal is the first Applying a second n-type diffusion layer forming composition larger than the n-type diffusion layer forming composition to form a second composition layer, and the first composition layer and the second composition The semiconductor substrate on which the layer is formed is subjected to a thermal diffusion treatment, and the second on the semiconductor substrate The n + -type diffusion layer in a region where the composition layer is formed of, n ++ type diffusion layer having the n + -type diffusion small surface sheet resistance than layer on the first composition layer is formed regions Are respectively formed, and a step of forming an electrode on the n ++ type diffusion layer.
＜１５＞　前記第一のｎ型拡散層形成組成物中におけるアルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が１０質量％以下であり、前記第二のｎ型拡散層形成組成物中におけるアルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が０．０１質量％以上５０質量％以下である前記＜１４＞に記載の太陽電池素子の製造方法である。 <15> The content of the metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in the first n-type diffusion layer forming composition is 10% by mass or less. The content of the metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals in the second n-type diffusion layer forming composition is 0.01% by mass or more and 50% by mass. % Is the method for producing a solar cell element according to <14>.
＜１６＞　半導体基板上に、前記＜１＞～＜１１＞のいずれか１項に記載のｎ型拡散層形成組成物の少なくとも１種を付与して組成物層を形成する工程と、前記組成物層が形成された半導体基板に熱拡散処理を施して、ｎ型拡散層を形成する工程と、前記ｎ型拡散層上に電極を形成する工程とを有する太陽電池素子の製造方法である。 <16> Forming a composition layer on a semiconductor substrate by applying at least one of the n-type diffusion layer forming composition according to any one of <1> to <11>, and the composition This is a method for manufacturing a solar cell element, which includes a step of forming a n-type diffusion layer by subjecting a semiconductor substrate on which a physical layer is formed to a thermal diffusion treatment and a step of forming an electrode on the n-type diffusion layer.
＜１７＞　ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物と、前記＜１＞～＜１１＞のいずれか１項に記載のｎ型拡散層形成組成物であり、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が前記第一のｎ型拡散層形成組成物よりも大きい第二のｎ型拡散層形成組成物とを含むｎ型拡散層形成組成物セット。 <17> A first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium, and the n-type diffusion layer forming composition according to any one of the above <1> to <11> A second n-type diffusion in which the content of the metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal is larger than that of the first n-type diffusion layer forming composition An n-type diffusion layer forming composition set comprising a layer forming composition.
　本発明によれば、特定の領域にｎ型拡散層を形成することができ、かつ、形成されるｎ型拡散層におけるドナー元素の拡散濃度を容易に調節することを可能にするｎ型拡散層形成組成物、これを用いたｎ型拡散層付き半導体基板の製造方法及び太陽電池素子の製造方法の提供をすることができる。 According to the present invention, an n-type diffusion layer can be formed in a specific region, and the diffusion concentration of the donor element in the formed n-type diffusion layer can be easily adjusted. A forming composition, a method for producing a semiconductor substrate with an n-type diffusion layer using the composition, and a method for producing a solar cell element can be provided.
本実施形態にかかる太陽電池素子の製造工程の一例を概念的に示す断面図である。It is sectional drawing which shows notionally an example of the manufacturing process of the solar cell element concerning this embodiment. 太陽電池素子を受光面から見た場合の電極の配置を概念的に示す平面図である。It is a top view which shows notionally the arrangement | positioning of the electrode at the time of seeing a solar cell element from a light-receiving surface. 図２Ａの一部を拡大して示す斜視図である。It is a perspective view which expands and shows a part of FIG. 2A. 本実施形態にかかる太陽電池素子の製造工程の別の一例を概念的に示す断面図である。It is sectional drawing which shows notionally another example of the manufacturing process of the solar cell element concerning this embodiment.
　まず、本発明のｎ型拡散層形成組成物について説明し、次にｎ型拡散層形成組成物を用いるｎ型拡散層付き半導体基板及び太陽電池素子の製造方法について説明する。
　なお、本明細書において「工程」との語は、独立した工程だけではなく、他の工程と明確に区別できない場合であってもその工程の所期の目的が達成されれば、本用語に含まれる。また「～」を用いて示された数値範囲は、「～」の前後に記載される数値をそれぞれ最小値及び最大値として含む範囲を示す。さらに組成物中の各成分の量は、組成物中に各成分に該当する物質が複数存在する場合、特に断らない限り、組成物中に存在する当該複数の物質の合計量を意味する。
　また、本明細書において、「含有率」とは、特に記載がなければ、ｎ型拡散層形成組成物１００質量％に対する成分の質量％を表す。 First, an n-type diffusion layer forming composition of the present invention will be described, and then a method for manufacturing a semiconductor substrate with an n-type diffusion layer and a solar cell element using the n-type diffusion layer forming composition will be described.
Note that in this specification, the term “process” is not limited to an independent process, and even if it cannot be clearly distinguished from other processes, the term “process” is used if the intended purpose of the process is achieved. included. A numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. Further, the amount of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition.
Moreover, in this specification, "content rate" represents the mass% of the component with respect to 100 mass% of n type diffused layer formation compositions, unless there is particular description.
＜ｎ型拡散層形成組成物＞
　本発明のｎ型拡散層形成組成物は、ドナー元素を含む化合物（Ａ）と、（前記ドナー元素を含む化合物とは異なる化合物であり、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物（Ｂ）と、分散媒（Ｃ）とを含有する。更に塗布性等を考慮してその他の添加剤を必要に応じて含有してもよい。
　本発明のｎ型拡散層形成組成物は、ドナー元素を含む化合物に加えて、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物（以下、「特定化合物」ともいう）を含むことで、特定化合物を含まないｎ型拡散層形成組成物を用いる場合よりも、ドナー元素の半導体基板への拡散性を抑制することができる。そのため例えば、半導体基板においてドナー元素の拡散濃度を他の領域よりも低く調節したい領域に本発明のｎ型拡散層形成組成物を付与し、他の領域に特定化合物を含まないｎ型拡散層形成組成物を付与して熱拡散処理を行うことで、所望の領域におけるドナー元素の拡散濃度を選択的に低く調節することが容易にできる。すなわち半導体基板の同一面内に選択的にドナー元素の拡散濃度が異なる領域を容易に形成することが可能である。この理由について、以下のように考えることができる。 <N-type diffusion layer forming composition>
The n-type diffusion layer forming composition of the present invention is a compound (A) containing a donor element and a compound different from the compound containing a donor element (at least selected from the group consisting of alkaline earth metals and alkali metals). It contains a metal compound (B) containing one kind of metal element and a dispersion medium (C), and may contain other additives as required in consideration of coating properties and the like.
The n-type diffusion layer forming composition of the present invention comprises a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals (hereinafter referred to as “specific”) in addition to the compound containing a donor element. By including the compound ”, the diffusibility of the donor element into the semiconductor substrate can be suppressed as compared with the case of using the n-type diffusion layer forming composition not containing the specific compound. Therefore, for example, in the semiconductor substrate, the n-type diffusion layer forming composition of the present invention is applied to a region where the diffusion concentration of the donor element is desired to be adjusted to be lower than other regions, and the n-type diffusion layer formation containing no specific compound is performed in the other regions. By applying the thermal diffusion treatment with the composition, the diffusion concentration of the donor element in a desired region can be easily adjusted to be low. That is, it is possible to easily form a region where the diffusion concentration of the donor element is selectively different in the same plane of the semiconductor substrate. The reason for this can be considered as follows.
　一般的に、ドナー元素を含む化合物として好適に用いられるＰ２Ｏ５（又は８００℃以上においてＰ２Ｏ５を含む化合物へ変化する材料）及びＰ２Ｏ３はいずれも酸性酸化物である。これらはＰ２Ｏ５又はＰ２Ｏ３として半導体基板中へ拡散すると考えられている。ｎ型拡散層形成組成物に前記特定化合物が含有されていると、ドナー元素を含む化合物と半導体基板との反応性よりも、ドナー元素を含む化合物と特定化合物との反応性の方が高いため、ドナー元素の半導体基板中への拡散性を抑制することができると考えられる。特に、前記特定化合物が塩基性化合物の場合、特定化合物とドナー元素を含む化合物との間で酸塩基反応が起こり、この酸塩基反応は反応性が高いため、より効果的にドナー元素の半導体基板中への拡散を抑制することができると考えられる。 In general, P 2 O 5 (or a material that changes to a compound containing P 2 O 5 at 800 ° C. or higher) and P 2 O 3 that are preferably used as a compound containing a donor element are both acidic oxides. These are believed to diffuse into the semiconductor substrate as P 2 O 5 or P 2 O 3 . When the specific compound is contained in the n-type diffusion layer forming composition, the reactivity between the compound containing the donor element and the specific compound is higher than the reactivity between the compound containing the donor element and the semiconductor substrate. It is considered that the diffusibility of the donor element into the semiconductor substrate can be suppressed. In particular, when the specific compound is a basic compound, an acid-base reaction occurs between the specific compound and the compound containing the donor element, and the acid-base reaction is highly reactive, so the semiconductor substrate of the donor element is more effective. It is thought that diffusion into the inside can be suppressed.
　また、前記特定化合物は、有機物とは異なり、高温（例えば５００℃以上）でも安定であるため、ドナー元素を半導体基板に拡散させる際に、本発明の効果を十分に発揮することができる。
　さらに特定化合物は、半導体基板に溶け込んだ場合でも、半導体基板中でキャリアの再結合中心として作用しないため、半導体基板を太陽電池に適用した場合における変換効率の低下という不具合の発生を抑えることができる。 In addition, unlike the organic substance, the specific compound is stable even at a high temperature (for example, 500 ° C. or higher), so that the effect of the present invention can be sufficiently exerted when the donor element is diffused into the semiconductor substrate.
Furthermore, even when the specific compound is dissolved in the semiconductor substrate, it does not act as a carrier recombination center in the semiconductor substrate, so that it is possible to suppress the occurrence of a problem that the conversion efficiency is lowered when the semiconductor substrate is applied to a solar cell. .
　さらに前記ｎ型拡散層形成組成物における特定化合物の含有量を適宜調節することで、半導体基板へのドナー元素の拡散濃度をより精密に調節することができる。さらにまた特定化合物を含むことで、ドナー元素を含む化合物が揮発性の高い化合物であっても、アウトディフュージョンを抑制することができる。これは例えば、特定化合物がドナー元素を含む化合物と化学的な相互作用することで、ドナー元素を含む化合物の揮発性が抑制されるためと考えられる。 Further, by appropriately adjusting the content of the specific compound in the n-type diffusion layer forming composition, the diffusion concentration of the donor element into the semiconductor substrate can be adjusted more precisely. Furthermore, by including the specific compound, out diffusion can be suppressed even if the compound containing the donor element is a highly volatile compound. This is considered to be because, for example, the volatility of the compound containing the donor element is suppressed by the chemical interaction of the specific compound with the compound containing the donor element.
　さらに本発明は、従来は複数回の熱拡散処理とマスキングによる部分エッチング等とを組み合わせた複雑な製造工程が必要であった選択エミッタ構造を、簡便な製造工程、例えば、一度の熱拡散処理で形成することを可能にするという効果を有する。 Furthermore, the present invention provides a selective emitter structure that has conventionally required a complicated manufacturing process combining a plurality of thermal diffusion processes and partial etching by masking, etc., with a simple manufacturing process, for example, a single thermal diffusion process. It has the effect of making it possible to form.
（Ａ）ドナー元素を含む化合物
　ドナー元素とは、半導体基板中に熱拡散することによってｎ型拡散層を形成することが可能な元素である。ドナー元素としては第１５族の元素が使用でき、安全性等の観点から、Ｐ（リン）が好適である。
　ドナー元素を含む化合物としては特に制限はない。ドナー元素を含む金属酸化物として、Ｐ２Ｏ５、Ｐ２Ｏ３等の単独金属酸化物；リンシリサイド、リンをドープしたシリコン粒子、リン酸カルシウム、リン酸、リンを含有するガラス粒子等の無機リン化合物；ホスホン酸、亜ホスホン酸、ホスフィン酸、亜ホスフィン酸、ホスフィン、ホスフィンオキシド、リン酸エステル、亜リン酸エステル等の有機リン化合物；などを例示することができる。
　これらの化合物のうち、有機リン化合物は、ドナー元素が半導体基板へ熱拡散する高温（例えば８００℃以上）においてＰ２Ｏ５を含む化合物へ変化し得る化合物である。 (A) Compound containing a donor element A donor element is an element capable of forming an n-type diffusion layer by thermal diffusion in a semiconductor substrate. As the donor element, a Group 15 element can be used, and P (phosphorus) is preferable from the viewpoint of safety and the like.
There is no restriction | limiting in particular as a compound containing a donor element. As a metal oxide containing a donor element, a single metal oxide such as P 2 O 5 or P 2 O 3 ; phosphorous silicide, silicon particles doped with phosphorus, calcium phosphate, phosphoric acid, phosphorus-containing glass particles, etc. Examples thereof include phosphonic acid, phosphonous acid, phosphinic acid, phosphinic acid, phosphine, phosphine oxide, phosphoric acid ester, phosphorous acid ester, etc.
Among these compounds, the organic phosphorus compound is a compound that can be changed to a compound containing P 2 O 5 at a high temperature (for example, 800 ° C. or higher) at which the donor element thermally diffuses into the semiconductor substrate.
　これらの中でもＰ２Ｏ３、Ｐ２Ｏ５及びドナー元素が半導体基板へ熱拡散する高温（例えば８００℃以上）においてＰ２Ｏ５を含む化合物へ変化し得る化合物（例えば、リン酸二水素アンモニウム、リン酸、亜ホスホン酸、ホスフィン酸、亜ホスフィン酸、ホスフィン、ホスフィンオキシド、リン酸エステル、亜リン酸エステル）からなる群より選ばれる少なくとも１種を用いることが好ましく、これらの中でも融点が１０００℃以下である化合物を用いることがより好ましい。これは、半導体基板へ熱拡散する際に、溶融状態となりやすく、半導体基板へ均一にドナー元素を熱拡散することができるためである。また、融点が１０００℃を超える化合物であっても、融点が１０００℃未満の化合物を更に添加することで、ドナー元素を含有する化合物から、融点が１０００℃未満の化合物を介して半導体基板へドナー元素が熱拡散するようにしてもよい。 Among these, a compound (for example, ammonium dihydrogen phosphate) that can be changed to a compound containing P 2 O 5 at a high temperature (for example, 800 ° C. or more) at which P 2 O 3 , P 2 O 5 and a donor element are thermally diffused into a semiconductor substrate. And at least one selected from the group consisting of phosphoric acid, phosphonous acid, phosphinic acid, phosphinic acid, phosphine, phosphine oxide, phosphate ester, phosphite ester). Among these, the melting point is 1000. It is more preferable to use a compound having a temperature of 0 ° C. or lower. This is because, when thermally diffusing to the semiconductor substrate, it is likely to be in a molten state, and the donor element can be uniformly thermally diffused to the semiconductor substrate. Even if the compound has a melting point of more than 1000 ° C., a compound having a melting point of less than 1000 ° C. is further added to the semiconductor substrate from the compound containing the donor element to the semiconductor substrate through the compound having a melting point of less than 1000 ° C. The element may be thermally diffused.
　前記ｎ型拡散層形成組成物におけるドナー元素を含む化合物が常温（２５℃）で粒子状である場合、粒子の場合の形状としては、略球状、扁平状、ブロック状、板状、鱗片状等が挙げられる。ｎ型拡散層形成組成物とした場合の基板への塗布性及び均一拡散性の点から、略球状、扁平状又は板状であることが好ましい。ドナー元素を含む化合物が固体の粒子状である場合、粒子の粒子径は、１００μｍ以下であることが好ましい。１００μｍ以下の粒子径を有する粒子を用いた場合には、平滑な組成物層が得られやすい。更に、ドナー元素を含む化合物が固体の粒子状である場合、粒子の粒子径は５０μｍ以下であることがより好ましい。なお、下限は特に制限されないが、０．０１μｍ以上であることが好ましく、０．１μｍ以上であることがより好ましい。なお、ドナー元素を含む化合物が固体の粒子状である場合の粒子の粒子径は体積平均粒子径を表し、レーザー散乱回折法粒度分布測定装置等により測定することができる。
　体積平均粒子径は、粒子に照射したレーザー光の散乱光強度と角度の関係を検出し、Ｍｉｅ散乱理論に基づいて算出することができる。測定する際の分散媒に特に制限はないが、測定対象とする粒子が溶解しない分散媒を用いることが好ましい。
　ドナー元素を含む化合物は分散媒に溶解した状態であってもよく、その場合、ｎ型拡散層形成組成物の調製に用いるドナー元素を含む化合物の形状及び粒子径には特に制限はない。 When the compound containing the donor element in the n-type diffusion layer forming composition is in the form of particles at normal temperature (25 ° C.), the shape in the case of particles is approximately spherical, flat, block, plate, scale, etc. Is mentioned. From the viewpoint of the coating property to the substrate and the uniform diffusibility when the n-type diffusion layer forming composition is used, the composition is preferably substantially spherical, flat or plate-like. When the compound containing a donor element is solid particles, the particle diameter of the particles is preferably 100 μm or less. When particles having a particle size of 100 μm or less are used, a smooth composition layer is easily obtained. Furthermore, when the compound containing a donor element is solid particles, the particle diameter of the particles is more preferably 50 μm or less. In addition, although a minimum in particular is not restrict | limited, It is preferable that it is 0.01 micrometer or more, and it is more preferable that it is 0.1 micrometer or more. In addition, the particle diameter of the particle | grains in case the compound containing a donor element is a solid particle form represents a volume average particle diameter, and can be measured with a laser scattering diffraction method particle size distribution measuring apparatus.
The volume average particle diameter can be calculated based on the Mie scattering theory by detecting the relationship between the scattered light intensity and the angle of the laser light applied to the particles. Although there is no restriction | limiting in particular in the dispersion medium at the time of measuring, It is preferable to use the dispersion medium which the particle | grains made into a measurement object do not melt | dissolve.
The compound containing the donor element may be in a state dissolved in the dispersion medium, and in that case, the shape and particle size of the compound containing the donor element used for preparing the n-type diffusion layer forming composition are not particularly limited.
　ｎ型拡散層形成組成物中のドナー元素を含む化合物の含有率は、塗布性、ドナー元素の拡散性等を考慮して決定される。一般には、ｎ型拡散層形成組成物中のドナー元素を含む化合物の含有率は、ｎ型拡散層形成組成物中に、０．１質量％以上９５質量％以下であることが好ましく、１質量％以上９０質量％以下であることがより好ましく、１質量％以上８０質量％以下であることがより好ましく、２質量％以上８０質量％以下であることがさらに好ましく、５質量％以上２０質量％以下であることが特に好ましい。
　ドナー元素を含む化合物の含有率が０．１質量％以上であると、ｎ型拡散層を十分に形成することができる。９５質量％以下であると、ｎ型拡散層形成組成物中のドナー元素を含む化合物の分散性が良好になり、半導体基板への塗布性が向上する。 The content rate of the compound containing the donor element in the n-type diffusion layer forming composition is determined in consideration of the coating property, the diffusibility of the donor element, and the like. In general, the content of the compound containing a donor element in the n-type diffusion layer forming composition is preferably 0.1% by mass or more and 95% by mass or less in the n-type diffusion layer forming composition. % To 90% by mass, more preferably 1% to 80% by mass, further preferably 2% to 80% by mass, and more preferably 5% to 20% by mass. It is particularly preferred that
When the content of the compound containing a donor element is 0.1% by mass or more, the n-type diffusion layer can be sufficiently formed. When the content is 95% by mass or less, the dispersibility of the compound containing the donor element in the n-type diffusion layer forming composition is improved, and the coating property to the semiconductor substrate is improved.
　前記ドナー元素を含む化合物は、ドナー元素を含むガラス粒子の形態であるものを用いることが好ましい。ここで、ガラスとはその原子配列にＸ線回折スペクトルにおいてに明確な結晶状態が認められず、不規則な網目構造をもち、かつ、ガラス転移現象を示す物質を指す。ドナー元素を含有するガラス粒子を用いることで、ｎ型拡散層形成組成物を付与した領域以外へのドナー元素の拡散（アウトディフュージョンという）をより効果的に抑制できる傾向にあり、裏面又は側面に不要なｎ型拡散層が形成されることが抑制できる。つまり、ドナー元素を含むガラス粒子を含むことで、より選択的にｎ型拡散層を形成することができる。 The compound containing a donor element is preferably a glass particle containing a donor element. Here, glass refers to a substance that has no irregular crystal structure in its X-ray diffraction spectrum, has an irregular network structure, and exhibits a glass transition phenomenon. By using glass particles containing a donor element, the diffusion of the donor element to a region other than the region to which the n-type diffusion layer forming composition is applied (referred to as out-diffusion) tends to be more effectively suppressed. The formation of an unnecessary n-type diffusion layer can be suppressed. That is, an n-type diffusion layer can be formed more selectively by including glass particles containing a donor element.
　ドナー元素を含むガラス粒子について、詳細に説明する。なお、本発明のｎ型拡散層形成組成物に含有されるガラス粒子は、熱拡散時の焼成温度（約８００℃～２０００℃）で溶融して、ｎ型拡散層の上にガラス層を形成する。そのためアウトディフュージョンをより抑制できる。ｎ型拡散層の形成後、ｎ型拡散層の上に形成されたガラス層は、エッチング（フッ酸水溶液等）により除去することができる。 The glass particles containing the donor element will be described in detail. The glass particles contained in the n-type diffusion layer forming composition of the present invention are melted at a firing temperature (about 800 ° C. to 2000 ° C.) during thermal diffusion to form a glass layer on the n-type diffusion layer. To do. Therefore, out diffusion can be further suppressed. After the formation of the n-type diffusion layer, the glass layer formed on the n-type diffusion layer can be removed by etching (hydrofluoric acid aqueous solution or the like).
　ドナー元素を含むガラス粒子は、例えばドナー元素含有物質とガラス成分物質とを含んで形成できる。ドナー元素をガラス粒子に導入するために用いるドナー元素含有物質としては、Ｐ（リン）を含有する化合物であることが好ましく、Ｐ２Ｏ３及びＰ２Ｏ５からなる群より選ばれる少なくとも１種であることがさらに好ましい。
　ドナー元素を含むガラス粒子中におけるドナー元素含有物質の含有率は特に制限されない。例えば、ドナー元素の拡散性の観点から、０．５質量％以上１００質量％以下であることが好ましく、２質量％以上８０質量％以下であることがより好ましい。さらに前記ドナー元素を含むガラス粒子は、ドナー元素の拡散性の観点から、ドナー元素含有物質としてＰ２Ｏ３及びＰ２Ｏ５からなる群より選ばれる少なくとも１種を０．５質量％以上１００質量％以下で含むことが好ましく、２質量％以上８０質量％以下で含むことがより好ましい。 The glass particles containing a donor element can be formed including, for example, a donor element-containing material and a glass component material. The donor element-containing material used for introducing the donor element into the glass particles is preferably a compound containing P (phosphorus), and at least one selected from the group consisting of P 2 O 3 and P 2 O 5 More preferably.
The content of the donor element-containing substance in the glass particles containing the donor element is not particularly limited. For example, from the viewpoint of the diffusibility of the donor element, the content is preferably 0.5% by mass or more and 100% by mass or less, and more preferably 2% by mass or more and 80% by mass or less. Furthermore, the glass particle containing the donor element contains 0.5% by mass or more of at least one selected from the group consisting of P 2 O 3 and P 2 O 5 as a donor element-containing substance from the viewpoint of diffusibility of the donor element. It is preferably contained in an amount of not more than mass%, more preferably not less than 2 mass% and not more than 80 mass%.
　また、ドナー元素を含むガラス粒子は、必要に応じてその成分比率を調節することによって、溶融温度、軟化点、ガラス転移点、化学的耐久性等を制御することが可能である。更に以下に記す、ガラス成分物質の少なくとも１種を含むことが好ましい。
　ガラス成分物質としては、ＳｉＯ２、Ｋ２Ｏ、Ｎａ２Ｏ、Ｌｉ２Ｏ、ＢａＯ、ＳｒＯ、ＣａＯ、ＭｇＯ、ＢｅＯ、ＺｎＯ、ＰｂＯ、ＣｄＯ、Ｔｌ２Ｏ、Ｖ２Ｏ５、ＳｎＯ、ＷＯ３、ＭｏＯ３、ＭｎＯ、Ｌａ２Ｏ３、Ｎｂ２Ｏ５、Ｔａ２Ｏ５、Ｙ２Ｏ３、ＣｓＯ２、ＴｉＯ２、ＺｒＯ２、ＧｅＯ２、ＴｅＯ２、Ｌｕ２Ｏ３等が挙げられる。中でもＳｉＯ２、Ｋ２Ｏ、Ｎａ２Ｏ、Ｌｉ２Ｏ、ＢａＯ、ＳｒＯ、ＣａＯ、ＭｇＯ、ＢｅＯ、ＺｎＯ、ＰｂＯ、ＣｄＯ、Ｖ２Ｏ５、ＳｎＯ、ＺｒＯ２、ＭｏＯ３、ＧｅＯ２、Ｙ２Ｏ３、ＣｓＯ２及びＴｉＯ２からなる群より選択される少なくとも１種を用いることが好ましく、ＳｉＯ２、Ｋ２Ｏ、Ｎａ２Ｏ、Ｌｉ２Ｏ、ＢａＯ、ＳｒＯ、ＣａＯ、ＭｇＯ、ＢｅＯ、ＺｎＯ、ＰｂＯ、ＣｄＯ、Ｖ２Ｏ５、ＳｎＯ、ＺｒＯ２及びＭｏＯ３からなる群より選択される少なくとも１種を用いることがより好ましい。 Moreover, the glass particle containing a donor element can control a melting temperature, a softening point, a glass transition point, chemical durability, etc. by adjusting the component ratio as needed. Furthermore, it is preferable to contain at least 1 sort (s) of the glass component material described below.
Examples of the glass component materials include SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, Tl 2 O, V 2 O 5 , SnO, and WO 3. , MoO 3 , MnO, La 2 O 3 , Nb 2 O 5 , Ta 2 O 5 , Y 2 O 3 , CsO 2 , TiO 2 , ZrO 2 , GeO 2 , TeO 2 , Lu 2 O 3 and the like. Among them SiO 2, K 2 O, Na 2 O, Li 2 O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V 2 O 5, SnO, ZrO 2, MoO 3, GeO 2, Y 2 It is preferable to use at least one selected from the group consisting of O 3 , CsO 2 and TiO 2 , SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO, SrO, CaO, MgO, BeO, ZnO. It is more preferable to use at least one selected from the group consisting of PbO, CdO, V 2 O 5 , SnO, ZrO 2 and MoO 3 .
　ドナー元素を含むガラス粒子の具体例としては、前記ドナー元素含有物質と前記ガラス成分物質の双方を含む系が挙げられる。具体的には、Ｐ２Ｏ５－ＳｉＯ２系（ドナー元素含有物質－ガラス成分物質の順で記載、以下同様）、Ｐ２Ｏ５－Ｋ２Ｏ系、Ｐ２Ｏ５－Ｎａ２Ｏ系、Ｐ２Ｏ５－Ｌｉ２Ｏ系、Ｐ２Ｏ５－ＢａＯ系、Ｐ２Ｏ５－ＳｒＯ系、Ｐ２Ｏ５－ＣａＯ系、Ｐ２Ｏ５－ＭｇＯ系、Ｐ２Ｏ５－ＢｅＯ系、Ｐ２Ｏ５－ＺｎＯ系、Ｐ２Ｏ５－ＣｄＯ系、Ｐ２Ｏ５－ＰｂＯ系、Ｐ２Ｏ５－Ｖ２Ｏ５系、Ｐ２Ｏ５－ＳｎＯ系、Ｐ２Ｏ５－ＧｅＯ２系、Ｐ２Ｏ５－ＴｅＯ２系等のドナー元素含有物質としてＰ２Ｏ５を含む系のガラス粒子、Ｐ２Ｏ５の代わりにＰ２Ｏ３を含む系のガラス粒子等が挙げられる。
　なお、Ｐ２Ｏ５－Ｓｂ２Ｏ３系、Ｐ２Ｏ５－Ａｓ２Ｏ３系等のように、２種類以上のドナー元素含有物質を含むガラス粒子でもよい。
　上記では２成分を含む複合ガラスを例示したが、Ｐ２Ｏ５－ＳｉＯ２－Ｖ２Ｏ５、Ｐ２Ｏ５－ＳｉＯ２－ＣａＯ等、３成分以上の物質を含むガラス粒子でもよい。 Specific examples of the glass particles containing a donor element include a system containing both the donor element-containing substance and the glass component substance. Specifically, P 2 O 5 —SiO 2 system (in the order of donor element-containing material—glass component material, the same shall apply hereinafter), P 2 O 5 —K 2 O system, P 2 O 5 —Na 2 O system , P 2 O 5 -Li 2 O system, P 2 O 5 -BaO-based, P 2 O 5 -SrO based, P 2 O 5 -CaO-based, P 2 O 5 -MgO-based, P 2 O 5 -BeO system , P 2 O 5 —ZnO, P 2 O 5 —CdO, P 2 O 5 —PbO, P 2 O 5 —V 2 O 5 , P 2 O 5 —SnO, P 2 O 5 —GeO 2 systems include P 2 O 5 glass particles system containing P 2 O 5 as a donor element-containing substance -TeO 2 system or the like, glass particles or the like system containing P 2 O 3 instead of P 2 O 5 .
Note that glass particles containing two or more kinds of donor element-containing substances such as P 2 O 5 —Sb 2 O 3 series, P 2 O 5 —As 2 O 3 series, and the like may be used.
In the above, a composite glass containing two components is exemplified, but glass particles containing three or more components such as P 2 O 5 —SiO 2 —V 2 O 5 and P 2 O 5 —SiO 2 —CaO may be used.
　前記ガラス粒子は、Ｐ２Ｏ３及びＰ２Ｏ５からなる群より選択される少なくとも１種のドナー元素含有物質と、ＳｉＯ２、Ｋ２Ｏ、Ｎａ２Ｏ、Ｌｉ２Ｏ、ＢａＯ、ＳｒＯ、ＣａＯ、ＭｇＯ、ＢｅＯ、ＺｎＯ、ＰｂＯ、ＣｄＯ、Ｖ２Ｏ５、ＳｎＯ、ＺｒＯ２、ＭｏＯ３、ＧｅＯ２、Ｙ２Ｏ３、ＣｓＯ２及びＴｉＯ２からなる群より選択される少なくとも１種のガラス成分物質と、を含有することが好ましく、Ｐ２Ｏ３及びＰ２Ｏ５からなる群より選択される少なくとも１種のドナー元素含有物質と、ＳｉＯ２、Ｋ２Ｏ、Ｎａ２Ｏ、Ｌｉ２Ｏ、ＢａＯ、ＳｒＯ、ＣａＯ、ＭｇＯ、ＢｅＯ、ＺｎＯ、ＰｂＯ、ＣｄＯ、Ｖ２Ｏ５、ＳｎＯ、ＺｒＯ２及びＭｏＯ３からなる群より選択される少なくとも１種のガラス成分物質と、を含有することがより好ましく、Ｐ２Ｏ５であるドナー元素含有物質と、ＳｉＯ２、ＺｎＯ、ＣａＯ、Ｎａ２Ｏ、Ｌｉ２Ｏ及びＢａＯからなる群より選択される少なくとも１種のガラス成分物質とを含有することがさらに好ましい。これにより、形成されるｎ型拡散層のシート抵抗をより低くすることが可能となる。 The glass particles include at least one donor element-containing material selected from the group consisting of P 2 O 3 and P 2 O 5 , SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO, SrO, At least one glass selected from the group consisting of CaO, MgO, BeO, ZnO, PbO, CdO, V 2 O 5 , SnO, ZrO 2 , MoO 3 , GeO 2 , Y 2 O 3 , CsO 2 and TiO 2. And at least one donor element-containing material selected from the group consisting of P 2 O 3 and P 2 O 5 , and SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO, SrO, CaO, MgO, BeO, ZnO, PbO, CdO, V 2 O 5, SnO, at least one glass selected from the group consisting of ZrO 2 and MoO 3 More preferably containing a minute substance, a donor element-containing material is a P 2 O 5, SiO 2, ZnO, CaO, Na 2 O, at least one selected from the group consisting of Li 2 O and BaO It is more preferable to contain these glass component substances. Thereby, the sheet resistance of the n-type diffusion layer to be formed can be further reduced.
　ガラス粒子中のＳｉＯ２及びＧｅＯ２からなる群より選択されるガラス成分物質（以下、「特定ガラス成分物質」ともいう）の含有比率は、溶融温度、軟化点、ガラス転移点、化学的耐久性を考慮して適宜設定することが好ましい。一般には特定ガラス成分物質が、ガラス粒子１００質量％中に、０．０１質量％以上８０質量％以下であることが好ましく、０．１質量％以上５０質量％以下であることがより好ましい。０．０１質量％以上であると、ｎ型拡散層を効率よく形成することができる。また８０質量％以下であると、ｎ型拡散層形成組成物を付与していない部分へのｎ型拡散層の形成をより効果的に抑制できる。 The content ratio of the glass component material selected from the group consisting of SiO 2 and GeO 2 in the glass particles (hereinafter also referred to as “specific glass component material”) is the melting temperature, softening point, glass transition point, chemical durability. It is preferable to set appropriately considering the above. In general, the specific glass component substance is preferably 0.01% by mass or more and 80% by mass or less, and more preferably 0.1% by mass or more and 50% by mass or less in 100% by mass of the glass particles. An n-type diffused layer can be efficiently formed as it is 0.01 mass% or more. Moreover, formation of the n-type diffusion layer in the part which has not provided the n-type diffusion layer formation composition as it is 80 mass% or less can be suppressed more effectively.
　ガラス粒子は特定ガラス成分物質以外に網目修飾酸化物（例えばアルカリ酸化物、アルカリ土類酸化物）又は単独ではガラス化しない中間酸化物を含んでいてもよい。具体的には、Ｐ２Ｏ５－ＳｉＯ２－ＣａＯ系ガラスの場合には、網目修飾酸化物であるＣａＯの含有比率は、１質量％以上３０質量％以下であることが好ましく、５質量％以上２０質量％以下であることがより好ましい。 In addition to the specific glass component substance, the glass particles may contain a network-modified oxide (for example, alkali oxide or alkaline earth oxide) or an intermediate oxide that does not vitrify alone. Specifically, in the case of P 2 O 5 —SiO 2 —CaO-based glass, the content ratio of CaO that is a network modification oxide is preferably 1% by mass to 30% by mass, and preferably 5% by mass. More preferably, it is 20 mass% or less.
　ガラス粒子の軟化点は、拡散処理時の拡散性及び液だれの観点から、２００℃～１０００℃であることが好ましく、３００℃～９００℃であることがより好ましい。なお、ガラス粒子の軟化点は示差熱・熱重量同時測定装置を用いて、示差熱（ＤＴＡ）曲線により求められる。具体的には、ＤＴＡ曲線の低温から第３番目のピークの値を軟化点とすることができる。 The softening point of the glass particles is preferably 200 ° C. to 1000 ° C., more preferably 300 ° C. to 900 ° C., from the viewpoints of diffusibility and dripping during the diffusion treatment. The softening point of the glass particles can be obtained from a differential heat (DTA) curve using a differential heat / thermogravimetric simultaneous measurement apparatus. Specifically, the value of the third peak from the low temperature of the DTA curve can be set as the softening point.
　ドナー元素を含むガラス粒子は、以下の手順で作製される。
　最初に原料、例えば、前記ドナー元素含有物質とガラス成分物質を秤量し、るつぼに充填する。るつぼの材質としては白金、白金―ロジウム、イリジウム、アルミナ、石英、炭素等が挙げられるが、溶融温度、雰囲気、溶融物質との反応性等を考慮して適宜選ばれる。
　次に、電気炉でガラス組成に応じた温度で加熱して融液とする。このとき融液が均一となるよう攪拌することが好ましい。続いて得られた融液をジルコニア基板、カーボン基板等の上に流し出して融液をガラス化する。最後にガラスを粉砕して粉末状とする。粉砕にはジェットミル、ビーズミル、ボールミル等の公知の方法が適用できる。 Glass particles containing a donor element are produced by the following procedure.
First, raw materials, for example, the donor element-containing material and the glass component material are weighed and filled in a crucible. Examples of the material for the crucible include platinum, platinum-rhodium, iridium, alumina, quartz, carbon, and the like, and are appropriately selected in consideration of the melting temperature, atmosphere, reactivity with the molten material, and the like.
Next, it heats with the temperature according to a glass composition with an electric furnace, and is set as a melt. At this time, stirring is preferably performed so that the melt becomes uniform. Subsequently, the obtained melt is poured onto a zirconia substrate, a carbon substrate, or the like to vitrify the melt. Finally, the glass is pulverized into powder. A known method such as a jet mill, a bead mill, or a ball mill can be applied to the pulverization.
　ドナー元素を含む化合物としてドナー元素を含有するガラス粒子を用いる場合、ガラス粒子中のドナー元素の含有率は、拡散性能の観点から、ガラス粒子中に、０．０１質量％以上４０質量％以下であることが好ましく、０．１質量%以上３５質量％以下であることが好ましく、１質量%以上３０質量％以下であることがさらに好ましい。
　またドナー元素を含む化合物としてドナー元素を含有するガラス粒子を用いる場合、ｎ型拡散層形成組成物におけるガラス粒子の含有率は、拡散の均一性の観点から、ｎ型拡散層形成組成物中に、１質量％以上８０質量％以下であることが好ましく、５質量%以上６０質量％以下であることが好ましく、１０質量%以上４０質量％以下であることがさらに好ましい。 When glass particles containing a donor element are used as the compound containing a donor element, the content of the donor element in the glass particles is 0.01% by mass or more and 40% by mass or less in the glass particles from the viewpoint of diffusion performance. Preferably, it is 0.1 to 35% by mass, more preferably 1 to 30% by mass.
Moreover, when using the glass particle containing a donor element as a compound containing a donor element, the content rate of the glass particle in an n type diffused layer formation composition is in an n type diffused layer formation composition from a viewpoint of the uniformity of diffusion. It is preferably 1% by mass or more and 80% by mass or less, more preferably 5% by mass or more and 60% by mass or less, and further preferably 10% by mass or more and 40% by mass or less.
（Ｂ）アルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属化合物
　本発明のｎ型拡散層形成組成物は、前記ドナー元素を含む化合物とは異なる化合物であって、アルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属化合物（特定化合物）の少なくもと１種を含む。これにより半導体基板へのドナー元素の拡散濃度を容易に制御することができる。具体的には、ドナー元素を含む化合物に加えて、アルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属化合物を含むｎ型拡散層形成組成物を用いることで、アルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属化合物を含有しないｎ型拡散層形成組成物を用いた場合よりも、ドナー元素の拡散濃度が低いｎ型拡散層を形成することができる。
　ここで、特定化合物（Ｂ）がドナー元素を含む化合物（Ａ）とは異なる化合物であるとは、例えば、ドナー元素を含む化合物（Ａ）がガラス粒子であって、ガラス粒子を構成するガラス成分物質としてアルカリ土類金属又はアルカリ金属を含む化合物を含有する場合であっても、本発明のｎ型拡散層形成組成物が特定化合物（Ｂ）を、ドナー元素を含む化合物（Ａ）とは独立して含有することを意味するものである。 (B) Metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals The n-type diffusion layer forming composition of the present invention is a compound different from the compound containing the donor element. And at least one metal compound (specific compound) containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals. Thereby, the diffusion concentration of the donor element to the semiconductor substrate can be easily controlled. Specifically, in addition to the compound containing a donor element, an n-type diffusion layer forming composition containing a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals is used. Thus, the diffusion concentration of the donor element is higher than when the n-type diffusion layer forming composition not containing a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals is used. An n-type diffusion layer having a low thickness can be formed.
Here, the specific compound (B) is a compound different from the compound (A) containing the donor element, for example, the compound (A) containing the donor element is a glass particle, and the glass component constituting the glass particle Even when an alkaline earth metal or a compound containing an alkali metal is contained as a substance, the n-type diffusion layer forming composition of the present invention is independent of the compound (A) containing the specific compound (B) and the donor element. Is meant to be contained.
　アルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属化合物は常温（約２０℃）で液体であるものであっても、固体であるものでもよい。ドナー元素の熱拡散温度が高温であることから、熱拡散処理する高温（例えば５００℃以上）において固体状の化合物であることが好ましい。ここで、例えば、アルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属化合物としては、アルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属酸化物、及びアルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属塩が挙げられる。 The metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals may be a liquid at room temperature (about 20 ° C.) or a solid. Since the thermal diffusion temperature of the donor element is high, it is preferably a solid compound at a high temperature (for example, 500 ° C. or higher) at which thermal diffusion treatment is performed. Here, for example, the metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals is at least one type selected from the group consisting of alkaline earth metals and alkali metals. And metal salts containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals.
　アルカリ土類金属及びアルカリ金属からなる群より選択される少なくとも１種の金属元素を含有する金属化合物（特定化合物）は、ドナー元素を熱拡散する７００℃以上の高温において、塩基性化合物に変化する化合物であることが好ましい。中でも強い塩基性を示す観点から、特定化合物は、金属元素としてマグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される少なくとも１種の金属元素を含有することが好ましく、マグネシウム、カルシウム、カリウム及びバリウムからなる群より選択される少なくとも１種の金属元素を含有することがより好ましく、マグネシウム、カルシウム及びカリウムからなる群より選択される少なくとも１種の金属元素を含有することがさらに好ましい。また化学的安定性の観点から、特定化合物は、これらの金属元素からなる群より選択される少なくとも１種を含有する金属酸化物、金属炭酸塩、金属硝酸塩、金属硫酸塩及び金属水酸化物からなる群より選択される少なくとも１種であることが好ましく、金属酸化物、金属炭酸塩及び金属水酸化物からなる群より選択される少なくとも１種であることが特に好ましい。 A metal compound (specific compound) containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal changes to a basic compound at a high temperature of 700 ° C. or higher at which a donor element is thermally diffused. A compound is preferred. Among these, from the viewpoint of showing strong basicity, the specific compound is at least one metal element selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium as the metal element. It is preferable to contain at least one metal element selected from the group consisting of magnesium, calcium, potassium and barium, and at least one selected from the group consisting of magnesium, calcium and potassium It is more preferable to contain these metal elements. Further, from the viewpoint of chemical stability, the specific compound is selected from metal oxides, metal carbonates, metal nitrates, metal sulfates and metal hydroxides containing at least one selected from the group consisting of these metal elements. It is preferably at least one selected from the group consisting of, and particularly preferably at least one selected from the group consisting of metal oxides, metal carbonates, and metal hydroxides.
　特定化合物としては、特に、酸化ナトリウム、酸化カリウム、酸化リチウム、酸化カルシウム、酸化マグネシウム、酸化ルビジウム、酸化セシウム、酸化ベリリウム、酸化ストロンチウム、酸化バリウム、酸化ラジウム等の金属酸化物及びこれらの複合酸化物；水酸化ナトリウム、水酸化カリウム、水酸化リチウム、水酸化カルシウム、水酸化マグネシウム、水酸化ルビジウム、水酸化セシウム、水酸化ベリリウム、水酸化ストロンチウム、水酸化バリウム、水酸化ラジウム等の金属水酸化物；炭酸ナトリウム、炭酸カリウム、炭酸リチウム、炭酸カルシウム、炭酸マグネシウム、炭酸ルビジウム、炭酸セシウム、炭酸ベリリウム、炭酸ストロンチウム、炭酸バリウム、炭酸ラジウム等の金属炭酸塩；硝酸ナトリウム、硝酸カリウム、硝酸リチウム、硝酸カルシウム、硝酸マグネシウム、硝酸ルビジウム、硝酸セシウム、硝酸ベリリウム、硝酸ストロンチウム、硝酸バリウム、硝酸ラジウム等の金属硝酸塩；硫酸ナトリウム、硫酸カリウム、硫酸リチウム、硫酸カルシウム、硫酸マグネシウム、硫酸ルビジウム、硫酸セシウム、硫酸ベリリウム、硫酸ストロンチウム、硫酸バリウム、硫酸ラジウム等の金属硫酸塩；などを用いることが好ましい。
　特定化合物は、好ましくは、前記金属酸化物及びこれらの複合酸化物、金属水酸化物、並びに金属炭酸塩からなる群より選択される少なくとも１種である。 Specific compounds include metal oxides such as sodium oxide, potassium oxide, lithium oxide, calcium oxide, magnesium oxide, rubidium oxide, cesium oxide, beryllium oxide, strontium oxide, barium oxide, radium oxide, and complex oxides thereof. Metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, rubidium hydroxide, cesium hydroxide, beryllium hydroxide, strontium hydroxide, barium hydroxide, radium hydroxide Metal carbonates such as sodium carbonate, potassium carbonate, lithium carbonate, calcium carbonate, magnesium carbonate, rubidium carbonate, cesium carbonate, beryllium carbonate, strontium carbonate, barium carbonate, radium carbonate; sodium nitrate, potassium nitrate, lithium nitrate Metal nitrates such as sodium, calcium sulfate, magnesium nitrate, rubidium nitrate, cesium nitrate, beryllium nitrate, strontium nitrate, barium nitrate, radium nitrate; sodium sulfate, potassium sulfate, lithium sulfate, calcium sulfate, magnesium sulfate, rubidium sulfate, cesium sulfate It is preferable to use metal sulfates such as beryllium sulfate, strontium sulfate, barium sulfate, and radium sulfate.
The specific compound is preferably at least one selected from the group consisting of the metal oxides and their composite oxides, metal hydroxides, and metal carbonates.
　これらの中でも、特定化合物は、低毒性及び入手の容易さという観点から、炭酸ナトリウム、酸化ナトリウム、炭酸カリウム、酸化カリウム、炭酸カルシウム、水酸化カルシウム、酸化カルシウム、炭酸マグネシウム、水酸化マグネシウム、硫酸マグネシウム、硫酸カルシウム、硝酸マグネシウム、硝酸カルシウム及び酸化マグネシウムからなる群より選択される少なくとも１種を用いることが好ましく、炭酸カリウム、酸化カリウム、酸化マグネシウム、酸化カルシウム、炭酸マグネシウム、炭酸カルシウム、硫酸マグネシウム、硫酸カルシウム、硝酸マグネシウム、硝酸カルシウム、水酸化マグネシウム及び水酸化カルシウムからなる群より選択される少なくとも１種を用いることがより好ましく、炭酸カリウム、酸化カリウム、炭酸カルシウム、酸化カルシウム、水酸化カルシウム、炭酸マグネシウム、酸化マグネシウム及び水酸化マグネシウムからなる群より選択される少なくとも１種を用いることがさらに好ましく、酸化カリウム、炭酸カルシウム、酸化カルシウム、水酸化カルシウム、炭酸マグネシウム、酸化マグネシウム及び水酸化マグネシウムからなる群より選択される少なくとも１種を用いることが特に好ましい。 Among these, the specific compounds are sodium carbonate, sodium oxide, potassium carbonate, potassium oxide, calcium carbonate, calcium hydroxide, calcium oxide, magnesium carbonate, magnesium hydroxide, magnesium sulfate from the viewpoint of low toxicity and availability. Preferably, at least one selected from the group consisting of calcium sulfate, magnesium nitrate, calcium nitrate and magnesium oxide is used, and potassium carbonate, potassium oxide, magnesium oxide, calcium oxide, magnesium carbonate, calcium carbonate, magnesium sulfate, sulfuric acid It is more preferable to use at least one selected from the group consisting of calcium, magnesium nitrate, calcium nitrate, magnesium hydroxide and calcium hydroxide, potassium carbonate, potassium oxide, carbonic acid More preferably, at least one selected from the group consisting of lucium, calcium oxide, calcium hydroxide, magnesium carbonate, magnesium oxide and magnesium hydroxide is used, and potassium oxide, calcium carbonate, calcium oxide, calcium hydroxide and magnesium carbonate are more preferable. It is particularly preferable to use at least one selected from the group consisting of magnesium oxide and magnesium hydroxide.
　特定化合物が常温で固体の粒子状である場合、その粒子の粒子径は０．０１μｍ以上３０μｍ以下であることが好ましく、０．０２μｍ以上１０μｍ以下であることがより好ましく、０．０３μｍ以上５μｍ以下であることが更に好ましい。粒子径が３０μｍ以下であると、半導体基板上のｎ型拡散層形成組成物の付与領域により均一にドナー元素を拡散（ドープ）することができる。また、０．０１μｍ以上であると、ｎ型層形成組成物中により均一に特定化合物を分散できる傾向にある。また、特定化合物は分散媒に溶解していてもよい。
　なお、粒子径は、体積平均粒子径を表し、レーザー散乱回折法粒度分布測定装置等により測定することができる。 When the specific compound is in the form of solid particles at normal temperature, the particle diameter of the particles is preferably 0.01 μm or more and 30 μm or less, more preferably 0.02 μm or more and 10 μm or less, and 0.03 μm or more and 5 μm or less. More preferably. When the particle diameter is 30 μm or less, the donor element can be uniformly diffused (doped) by the application region of the n-type diffusion layer forming composition on the semiconductor substrate. Moreover, it exists in the tendency which can disperse | distribute a specific compound more uniformly in n type layer forming composition as it is 0.01 micrometer or more. The specific compound may be dissolved in the dispersion medium.
The particle diameter represents a volume average particle diameter, and can be measured with a laser scattering diffraction particle size distribution measuring apparatus or the like.
　粒子径が所望の範囲、例えば０．０１μｍ以上３０μｍ以下である特定化合物の固体粒子を得る方法としては特に制限はない。例えば粉砕処理をして得ることができる。粉砕手法としては、乾式粉砕法及び湿式粉砕法が採用できる。乾式粉砕法としては、ジェットミル、振動ミル、ボールミル等が採用できる。湿式粉砕法としては、ビーズミル、ボールミル等が採用できる。 There is no particular limitation on the method for obtaining solid particles of a specific compound having a particle diameter in a desired range, for example, 0.01 μm to 30 μm. For example, it can be obtained by pulverization. As a grinding method, a dry grinding method and a wet grinding method can be employed. As the dry pulverization method, a jet mill, a vibration mill, a ball mill, or the like can be employed. As the wet pulverization method, a bead mill, a ball mill or the like can be employed.
　粉砕処理に際して粉砕装置に起因する不純物がｎ型拡散層形成組成物に混入すると、半導体基板内のキャリアのライフタイム低下を招く恐れがあるため、粉砕容器、ビーズ、ボール等の材質は半導体基板への影響の少ない材質を選択することが好ましい。具体的には部分安定化ジルコニア等を使用することができる。また、粉砕手法以外に、気相酸化法、加水分解法等を用いて所望の特定化合物を得ることができる。 When impurities resulting from the pulverization apparatus are mixed into the n-type diffusion layer forming composition during the pulverization process, the lifetime of carriers in the semiconductor substrate may be reduced. It is preferable to select a material with less influence. Specifically, partially stabilized zirconia or the like can be used. In addition to the pulverization method, a desired specific compound can be obtained by using a gas phase oxidation method, a hydrolysis method, or the like.
　特定化合物の形状は特に制限されず、略球状、扁平状、鱗片状、ブロック状、楕球状、板状及び棒状のいずれであってもよい。なお、特定化合物の形状は走査型電子顕微鏡を用いて観察して判定することができる。 The shape of the specific compound is not particularly limited, and may be any of a substantially spherical shape, a flat shape, a scale shape, a block shape, an oval shape, a plate shape, and a rod shape. In addition, the shape of a specific compound can be determined by observing using a scanning electron microscope.
　また予め特定化合物と、ドナー元素を含む化合物とを反応させてもよい。具体的には例えば、酸化カルシウムをリン酸水溶液に浸漬して酸化カルシウム表面にリン化合物を固定した後、リン化合物が固定された酸化カルシウムをろ過により分離して得られる材料を、ドナー元素を含む化合物及び特定化合物として用いてもよい。 Further, the specific compound may be reacted in advance with a compound containing a donor element. Specifically, for example, a material obtained by immersing calcium oxide in a phosphoric acid aqueous solution to fix the phosphorus compound on the surface of the calcium oxide and then separating the calcium oxide to which the phosphorus compound is fixed by filtration includes a donor element. You may use as a compound and a specific compound.
　ｎ型拡散層形成組成物中の特定化合物の含有率は、塗布性及びドナー元素の半導体基板への拡散濃度等を考慮して決定される。一般には、ｎ型拡散層形成組成物中の特定化合物の含有率は、ｎ型拡散層形成組成物中に、０．０１質量％以上５０質量％以下であることが好ましく、０．０２質量％以上３０質量％以下であることがより好ましく、０．１質量％以上２０質量％以下であることがより好ましく、０．１質量％以上５質量％以下であることが特に好ましい。
　特定化合物の含有率が０．０１質量％以上であると、ドナー元素を含む化合物中に含まれるドナー元素の半導体基板への熱拡散を適度に抑制することができる。また、５０質量％以下であると、ドナー元素を含む化合物中に含まれるドナー元素の半導体基板への熱拡散を阻害しすぎることがない傾向にある。 The content of the specific compound in the n-type diffusion layer forming composition is determined in consideration of the coating property, the diffusion concentration of the donor element into the semiconductor substrate, and the like. In general, the content of the specific compound in the n-type diffusion layer forming composition is preferably 0.01% by mass or more and 50% by mass or less in the n-type diffusion layer forming composition, and is 0.02% by mass. It is more preferably 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, and particularly preferably 0.1% by mass or more and 5% by mass or less.
When the content of the specific compound is 0.01% by mass or more, thermal diffusion of the donor element contained in the compound containing the donor element to the semiconductor substrate can be appropriately suppressed. Moreover, it exists in the tendency which does not inhibit the thermal diffusion to the semiconductor substrate of the donor element contained in the compound containing a donor element too much that it is 50 mass% or less.
　ｎ型拡散層形成組成物中におけるドナー元素を含む化合物に対する前記特定化合物の含有比率は特に制限されない。ドナー元素の半導体基板への拡散の均一性の観点から、ドナー元素を含む化合物１００質量％に対して０．０１質量％以上１０質量％以下であることが好ましく、０．１質量％以上８質量％以下であることがより好ましく、０．５質量％以上６質量％以下であることがさらに好ましい。 The content ratio of the specific compound with respect to the compound containing a donor element in the n-type diffusion layer forming composition is not particularly limited. From the viewpoint of uniformity of diffusion of the donor element into the semiconductor substrate, it is preferably 0.01% by mass or more and 10% by mass or less, and 0.1% by mass or more and 8% by mass with respect to 100% by mass of the compound containing the donor element. % Or less, more preferably 0.5% by mass or more and 6% by mass or less.
（Ｃ）分散媒
　本発明のｎ型拡散層形成組成物は分散媒を含有する。
　分散媒とは、組成物中において前記ドナー元素を含む化合物及びアルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物を分散又は溶解させる媒体である。具体的に分散媒は、少なくとも溶剤又は水を含むことが好ましい。また分散媒としては、溶剤又は水に加え、後述する有機バインダを含有するものであってもよい。 (C) Dispersion medium The n-type diffusion layer forming composition of the present invention contains a dispersion medium.
The dispersion medium is a medium in which a compound containing the donor element and a metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal are dispersed or dissolved in the composition. Specifically, the dispersion medium preferably contains at least a solvent or water. Moreover, as a dispersion medium, in addition to a solvent or water, you may contain the organic binder mentioned later.
　溶剤としては、ケトン溶剤；エーテル溶剤；酢酸２－（２－ブトキシエトキシ）エチル等のエステル溶剤；非プロトン性極性溶剤；アルコール溶剤；ジエチレングリコールモノ－ｎ－ブチルエーテル等のグリコールモノエーテル溶剤；α－テルピネン等のテルピネン、α－テルピネオール等のテルピネオール、α－ピネン、β－ピネン等のピネン、ミルセン、アロオシメン、リモネン、ジペンテン、カルボン、オシメン、フェランドレンなどテルペン溶剤等が挙げられる。また溶剤としては特開２０１２－０８４８３０号公報に記載のものを用いてもよい。これらは１種類を単独で又は２種類以上を組み合わせて使用される。
　ｎ型拡散層形成組成物とした場合、基板への塗布性の観点から、テルペン溶剤、グリコールモノエーテル溶剤及びエステル溶剤からなる群より選ばれる少なくとも１種が好ましく、テルピネオール、ジエチレングリコールモノ－ｎ－ブチルエーテル又は酢酸２－（２－ブトキシエトキシ）エチルが好ましい。 Solvents include ketone solvents; ether solvents; ester solvents such as 2- (2-butoxyethoxy) ethyl acetate; aprotic polar solvents; alcohol solvents; glycol monoether solvents such as diethylene glycol mono-n-butyl ether; α-terpinene Terpinene such as α-terpineol, pinene such as α-pinene and β-pinene, terpene solvents such as myrcene, alloocimene, limonene, dipentene, carvone, osimene, and ferrandrene. As the solvent, those described in JP2012-084830A may be used. These are used singly or in combination of two or more.
In the case of an n-type diffusion layer forming composition, at least one selected from the group consisting of a terpene solvent, a glycol monoether solvent and an ester solvent is preferable from the viewpoint of applicability to the substrate. Terpineol, diethylene glycol mono-n-butyl ether Or 2- (2-butoxyethoxy) ethyl acetate is preferred.
　ｎ型拡散層形成組成物中の分散媒の含有率は、塗布性及びドナー元素の濃度を考慮して決定される。例えば、ｎ型拡散層形成組成物中に、５質量％以上９９質量％以下であることが好ましく、２０質量％以上９５質量％以下であることがより好ましく、４０質量％以上９０質量％以下であることがさらに好ましい。 The content of the dispersion medium in the n-type diffusion layer forming composition is determined in consideration of the coating property and the concentration of the donor element. For example, in the n-type diffusion layer forming composition, it is preferably 5% by mass or more and 99% by mass or less, more preferably 20% by mass or more and 95% by mass or less, and 40% by mass or more and 90% by mass or less. More preferably it is.
　本発明のｎ型拡散層形成組成物は、ドナー元素を含む化合物、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物、及び分散媒の他に、必要に応じて、有機バインダ、界面活性剤、無機粉末、ケイ素原子を含む樹脂、還元性添加剤、チキソ剤等を含有することができる。 The n-type diffusion layer forming composition of the present invention, in addition to a compound containing a donor element, a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals, and a dispersion medium, If necessary, an organic binder, a surfactant, an inorganic powder, a resin containing a silicon atom, a reducing additive, a thixotropic agent, and the like can be contained.
　前記ｎ型拡散層形成組成物は有機バインダの少なくとも１種を更に含有することができる。有機バインダを含むことで、ｎ型拡散層形成組成物としての粘度調節及びチキソ性の付与が可能となり、半導体基板への付与性がより向上する。有機バインダとしては、例えば、ポリビニルアルコール；ポリアクリルアミド樹脂；ポリビニルアミド樹脂；ポリビニルピロリドン樹脂；ポリエチレンオキサイド樹脂；ポリスルホン樹脂；アクリルアミドアルキルスルホン樹脂；セルロースエーテル、カルボキシメチルセルロース、ヒドロキシエチルセルロース、エチルセルロース等のセルロース誘導体；ゼラチン及びゼラチン誘導体；澱粉及び澱粉誘導体；アルギン酸ナトリウム及びアルギン酸ナトリウム誘導体；キサンタン及びキサンタン誘導体；グア及びグア誘導体；スクレログルカン及びスクレログルカン誘導体；トラガカント及びトラガカント誘導体；デキストリン及びデキストリン誘導体；（メタ）アクリル酸樹脂；アルキル（メタ）アクリレート樹脂、ジメチルアミノエチル（メタ）アクリレート樹脂等の（メタ）アクリル酸エステル樹脂；、ブタジエン樹脂；スチレン樹脂；並びにこれらの共重合体を適宜選択しうる。これらは１種類を単独で又は２種類以上を組み合わせて使用される。有機バインダを用いる場合は、分解性、取り扱いの簡便性の観点から、セルロース誘導体、アクリル樹脂誘導体、ポリエチレンオキサイド樹脂を用いることが好ましい。 The n-type diffusion layer forming composition may further contain at least one organic binder. By including the organic binder, it is possible to adjust the viscosity and impart thixotropy as the n-type diffusion layer forming composition, thereby further improving the impartability to the semiconductor substrate. Examples of the organic binder include polyvinyl alcohol; polyacrylamide resin; polyvinyl amide resin; polyvinyl pyrrolidone resin; polyethylene oxide resin; polysulfone resin; acrylamide alkyl sulfone resin; cellulose derivatives such as cellulose ether, carboxymethyl cellulose, hydroxyethyl cellulose, and ethyl cellulose; Starch and starch derivatives; sodium alginate and sodium alginate derivatives; xanthan and xanthan derivatives; gua and guar derivatives; scleroglucan and scleroglucan derivatives; tragacanth and tragacanth derivatives; Resin; alkyl (meth) acrylate resin, dimethylaminoethyl Meth) acrylates such as resin (meth) acrylic acid ester resin; butadiene resin; a styrene resin; and can select these copolymers as appropriate. These are used singly or in combination of two or more. When using an organic binder, it is preferable to use a cellulose derivative, an acrylic resin derivative, and a polyethylene oxide resin from the viewpoint of degradability and ease of handling.
　有機バインダの分子量は特に制限されず、組成物としての所望の粘度を鑑みて適宜調節することが好ましい。なお、有機バインダを含有する場合の含有量は、ｎ型拡散層形成組成物中に、０．５質量％以上３０質量％以下であることが好ましく、３質量％以上２５質量％以下であることがより好ましく、３質量％以上２０質量％以下であることがさらに好ましい。 The molecular weight of the organic binder is not particularly limited, and is preferably adjusted appropriately in view of the desired viscosity as the composition. In addition, it is preferable that content in the case of containing an organic binder is 0.5 mass% or more and 30 mass% or less in n type diffused layer formation composition, and is 3 mass% or more and 25 mass% or less. Is more preferable, and more preferably 3% by mass or more and 20% by mass or less.
　界面活性剤としては、ノニオン系界面活性剤、カチオン系界面活性剤、アニオン系界面活性剤等が挙げられる。中でも、半導体基板への重金属等の不純物の持ち込みが少ないことからノニオン系界面活性剤又はカチオン系界面活性剤が好ましい。
　ノニオン系界面活性剤としては、シリコン系界面活性剤、フッ素系界面活性剤、炭化水素系界面活性剤等が例示される。中でも拡散等の加熱時に速やかに焼成されることから、炭化水素系界面活性剤が好ましい。 Examples of the surfactant include a nonionic surfactant, a cationic surfactant, and an anionic surfactant. Among these, nonionic surfactants or cationic surfactants are preferable because impurities such as heavy metals are not brought into the semiconductor substrate.
Examples of nonionic surfactants include silicon surfactants, fluorine surfactants, hydrocarbon surfactants, and the like. Of these, hydrocarbon surfactants are preferred because they are rapidly fired during heating such as diffusion.
　炭化水素系界面活性剤としては、エチレンオキサイド－プロピレンオキサイドのブロック共重合体、アセチレングリコール化合物等が例示される。半導体基板のシート抵抗値のバラツキをより低減する観点から、アセチレングリコール化合物が好ましい。 Examples of hydrocarbon surfactants include ethylene oxide-propylene oxide block copolymers, acetylene glycol compounds, and the like. From the viewpoint of further reducing variation in the sheet resistance value of the semiconductor substrate, an acetylene glycol compound is preferred.
　無機粉末としては、フィラーとして機能しうる物質が好ましい。無機粉末としては、酸化ケイ素、酸化チタン、窒化ケイ素、炭化ケイ素の粉末等を挙げることができる。 The inorganic powder is preferably a substance that can function as a filler. Examples of the inorganic powder include silicon oxide, titanium oxide, silicon nitride, and silicon carbide powder.
　前記ｎ型拡散層形成組成物は、還元性化合物を含有してもよい。還元性化合物としては、ポリエチレングリコール、ポリプロピレングリコール等のポリアルキレングリコール、ポリアルキレングリコールの末端アルキル化物；グルコース、フルクトース、ガラクトース等の単糖類及び単糖類の誘導体；スクロース、マルトース等の二糖類及び二糖類の誘導体；多糖類及び多糖類の誘導体；などを挙げることができる。これらの有機化合物の中でも、ポリアルキレングリコールが好ましく、ポリプロピレングリコールが更に好ましい。還元性化合物を更に含むことで、ドナー元素の半導体基板への拡散が容易になる傾向がある。 The n-type diffusion layer forming composition may contain a reducing compound. Examples of reducing compounds include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, terminal alkylated products of polyalkylene glycols; monosaccharides such as glucose, fructose, and galactose, and derivatives of monosaccharides; disaccharides and disaccharides such as sucrose and maltose And polysaccharides and polysaccharide derivatives; and the like. Among these organic compounds, polyalkylene glycol is preferable, and polypropylene glycol is more preferable. By further containing a reducing compound, the diffusion of the donor element into the semiconductor substrate tends to be facilitated.
　前記ｎ型拡散層形成組成物は、固形分を含有するチキソ剤を含んでいてもよい。これにより容易にチキソ性を制御することができ、印刷に適切な粘度をもつスクリーン印刷用のｎ型拡散層形成組成物を構成することができる。さらにまた、チキソ性が制御されていることより、印刷時におけるｎ型拡散層形成組成物の印刷パターンからの滲み又はダレを抑制することができる。 The n-type diffusion layer forming composition may contain a thixotropic agent containing a solid content. Thereby, thixotropy can be easily controlled, and an n-type diffusion layer forming composition for screen printing having a viscosity suitable for printing can be constituted. Furthermore, since thixotropy is controlled, bleeding or sagging from the print pattern of the n-type diffusion layer forming composition during printing can be suppressed.
　本発明のｎ型拡散層形成組成物の製造方法は特に制限されない。例えばドナー元素を含む化合物、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物、分散媒及び必要に応じて加えられる成分をブレンダー、ミキサ、乳鉢、ローター等を用いて混合することで得ることができる。また、混合する際は、必要に応じて熱を加えてもよい。混合に際して加熱する場合、その温度は例えば３０℃～１００℃とすることができる。
　なお、前記ｎ型拡散層形成組成物中に含まれる成分、及び各成分の含有量はＴＧ／ＤＴＡ等の熱分析、ＮＭＲ、ＩＲ、ＭＡＬＤＩ－ＭＳ、ＧＣ－ＭＳ等のスペクトル分析、ＨＰＬＣ、ＧＰＣ等のクロマトグラフ分析などを用いて確認することができる。 The method for producing the n-type diffusion layer forming composition of the present invention is not particularly limited. For example, a compound containing a donor element, a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals, a dispersion medium, and components to be added as needed are blender, mixer, mortar, rotor It can obtain by mixing using etc. Moreover, when mixing, you may add a heat | fever as needed. When heating at the time of mixing, the temperature can be, for example, 30 ° C. to 100 ° C.
The components contained in the n-type diffusion layer forming composition, and the content of each component are thermal analysis such as TG / DTA, spectral analysis such as NMR, IR, MALDI-MS, GC-MS, HPLC, GPC It can be confirmed using chromatographic analysis.
　本発明のｎ型拡散層形成組成物における、ドナー元素を含む化合物と、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物と、分散媒との総含有率はｎ型拡散層形成組成物中に、１質量％以上であることが好ましく、５質量％以上であることがより好ましい。 In the n-type diffusion layer forming composition of the present invention, the total of the compound containing the donor element, the metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals, and the dispersion medium The content is preferably 1% by mass or more, more preferably 5% by mass or more in the n-type diffusion layer forming composition.
　本発明のｎ型拡散層形成組成物の好ましい態様は例えば以下の通りである。
　（１）Ｐ２Ｏ５及びＰ２Ｏ３からなる群より選ばれる少なくとも１種をドナー元素として含む化合物と、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される少なくとも１種の金属元素を含有する金属化合物と、分散媒とを含有するｎ型拡散層形成組成物である。
　（２）Ｐ２Ｏ５及びＰ２Ｏ３からなる群より選ばれる少なくとも１種をドナー元素として含むガラス粒子と、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される少なくとも１種の金属元素を含有する、金属酸化物、金属炭酸塩、金属硝酸塩、金属硫酸塩及び金属水酸化物からなる群より選択される少なくとも１種である金属化合物と、分散媒とを含有するｎ型拡散層形成組成物である。
　（３）Ｐ２Ｏ５及びＰ２Ｏ３からなる群より選ばれる少なくとも１種をドナー元素として含み、粒子径が０．０１μｍ以上１００μｍ以下であるガラス粒子と、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される少なくとも１種の金属元素を含有する、金属酸化物、金属炭酸塩、金属硝酸塩、金属硫酸塩及び金属水酸化物からなる群より選択される少なくとも１種であり、粒子径が０．０１μｍ以上３０μｍ以下である金属化合物粒子と、分散媒とを含有するｎ型拡散層形成組成物である。
　（４）Ｐ２Ｏ５及びＰ２Ｏ３からなる群より選ばれる少なくとも１種をドナー元素として含み、粒子径が０．０１μｍ以上１００μｍ以下であって、含有率が０．１質量％以上９５質量％以下であるガラス粒子と、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される少なくとも１種の金属元素を含有する、金属酸化物、金属炭酸塩、金属硝酸塩、金属硫酸塩及び金属水酸化物からなる群より選択される少なくとも１種であり、粒子径が０．０１μｍ以上３０μｍ以下であって、含有率が０．０１質量％以上５０質量％以下である金属化合物粒子と、分散媒とを含有するｎ型拡散層形成組成物である。
　（５）Ｐ２Ｏ５及びＰ２Ｏ３からなる群より選ばれる少なくとも１種をドナー元素として含むガラス粒子と、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選択される少なくとも１種の金属元素を含有する、金属酸化物、金属炭酸塩、金属硝酸塩、金属硫酸塩及び金属水酸化物からなる群より選択される少なくとも１種である金属化合物と、分散媒とを含有し、前記ドナー元素を含むガラス粒子に対する前記金属化合物の含有比率が０．０１質量％以上１０質量％以下であるｎ型拡散層形成組成物である。 Preferred embodiments of the composition for forming an n-type diffusion layer of the present invention are as follows, for example.
(1) A compound containing at least one selected from the group consisting of P 2 O 5 and P 2 O 3 as a donor element, magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium An n-type diffusion layer forming composition containing a metal compound containing at least one metal element selected from the group consisting of and a dispersion medium.
(2) glass particles containing at least one selected from the group consisting of P 2 O 5 and P 2 O 3 as a donor element, magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium, and A metal that contains at least one metal element selected from the group consisting of radium and is at least one selected from the group consisting of metal oxides, metal carbonates, metal nitrates, metal sulfates, and metal hydroxides An n-type diffusion layer-forming composition containing a compound and a dispersion medium.
(3) Glass particles containing at least one selected from the group consisting of P 2 O 5 and P 2 O 3 as a donor element and having a particle size of 0.01 μm or more and 100 μm or less, magnesium, calcium, sodium, potassium, From metal oxides, metal carbonates, metal nitrates, metal sulfates and metal hydroxides containing at least one metal element selected from the group consisting of lithium, rubidium, cesium, beryllium, strontium, barium and radium An n-type diffusion layer forming composition comprising at least one selected from the group consisting of metal compound particles having a particle size of 0.01 μm or more and 30 μm or less, and a dispersion medium.
(4) At least one selected from the group consisting of P 2 O 5 and P 2 O 3 is included as a donor element, the particle diameter is 0.01 μm or more and 100 μm or less, and the content is 0.1% by mass or more and 95 Metal oxide containing glass particles having a mass% or less and at least one metal element selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium , At least one selected from the group consisting of metal carbonates, metal nitrates, metal sulfates and metal hydroxides, having a particle size of 0.01 μm or more and 30 μm or less, and a content of 0.01% by mass An n-type diffusion layer forming composition containing metal compound particles in an amount of 50% by mass or less and a dispersion medium.
(5) Glass particles containing as a donor element at least one selected from the group consisting of P 2 O 5 and P 2 O 3 , magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and A metal that contains at least one metal element selected from the group consisting of radium and is at least one selected from the group consisting of metal oxides, metal carbonates, metal nitrates, metal sulfates, and metal hydroxides It is an n-type diffusion layer forming composition containing a compound and a dispersion medium, wherein the content ratio of the metal compound to the glass particles containing the donor element is 0.01% by mass or more and 10% by mass or less.
　本発明のｎ型拡散層形成組成物は、ドナー元素を含む化合物に含有される金属及び特定化合物に含まれる金属以外に、他の金属を実質的に含有しないこと（０．５質量%以下）が好ましく、金属を含有しないこと（０質量％）がより好ましい。 The n-type diffusion layer forming composition of the present invention contains substantially no other metal other than the metal contained in the compound containing the donor element and the metal contained in the specific compound (0.5% by mass or less). Is preferable, and it is more preferable not to contain a metal (0 mass%).
＜ｎ型拡散層形成組成物セット＞
　本発明のｎ型拡散層形成組成物セットは、ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物と、ドナー元素を含む化合物、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物（特定化合物）、及び分散媒を含有し、前記特定化合物の含有率が前記第一のｎ型拡散層形成組成物よりも大きい第二のｎ型拡散層形成組成物とを含む。つまり、ｎ型拡散層形成組成物セットは、前記第一のｎ型拡散層形成組成物と前記第二のｎ型拡散層形成組成物との組合せ（セット）である。特定化合物の含有率が異なる２種以上のｎ型拡散層形成組成物を含むことで、ドナー元素の拡散濃度が異なる領域を有する半導体基板の製造に好適に用いることができる。 <N-type diffusion layer forming composition set>
The n-type diffusion layer forming composition set of the present invention includes a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium, a compound containing a donor element, an alkaline earth metal, and an alkali metal. A metal compound (specific compound) containing at least one metal element selected from the group consisting of, and a dispersion medium, wherein the content of the specific compound is larger than that of the first n-type diffusion layer forming composition. A second n-type diffusion layer forming composition. That is, the n-type diffusion layer forming composition set is a combination (set) of the first n-type diffusion layer forming composition and the second n-type diffusion layer forming composition. By including two or more types of n-type diffusion layer forming compositions having different specific compound contents, the composition can be suitably used for manufacturing a semiconductor substrate having regions having different diffusion concentrations of donor elements.
　前記第二のｎ型拡散層形成組成物の詳細は既述の通りである。
　前記第一のｎ型拡散層形成組成物における前記特定化合物の含有率は、前記第二のｎ型拡散層形成組成物における特定化合物の含有率よりも低い限り特に制限はない。特定化合物の含有率は、例えば第一のｎ型拡散層形成組成物中に１０質量％以下とすることができ、１質量％以下であることが好ましく、実質的に特定化合物を含まないことがより好ましい。ここで特定化合物を実質的に含まないとは特定化合物の不可避的な混入を妨げないことを意味する。 The details of the second n-type diffusion layer forming composition are as described above.
The specific compound content in the first n-type diffusion layer forming composition is not particularly limited as long as it is lower than the specific compound content in the second n-type diffusion layer forming composition. The content rate of the specific compound can be, for example, 10% by mass or less in the first n-type diffusion layer forming composition, preferably 1% by mass or less, and substantially free of the specific compound. More preferred. Here, that the specific compound is not substantially contained means that the inevitable mixing of the specific compound is not prevented.
　前記第一のｎ型拡散層形成組成物中の特定化合物の含有率に対する第二のｎ型拡散層形成組成物中の特定化合物の含有率の比は５以上であることが好ましく、１０以上であることがより好ましい。 The ratio of the specific compound content in the second n-type diffusion layer forming composition to the specific compound content in the first n-type diffusion layer forming composition is preferably 5 or more, and preferably 10 or more. More preferably.
＜ｎ型拡散層付き半導体基板の製造方法＞
　本発明のｎ型拡散層付き半導体基板の製造方法は、半導体基板上に、本発明のｎ型拡散層形成組成物を付与して組成物層を形成する工程と、前記組成物層が形成された半導体基板に熱処理を施す工程とを有する。前記ｎ型拡散層付き半導体基板の製造方法は必要に応じてその他の工程を更に有していてもよい。 <Method for manufacturing semiconductor substrate with n-type diffusion layer>
The method for producing a semiconductor substrate with an n-type diffusion layer according to the present invention comprises a step of forming a composition layer by applying the composition for forming an n-type diffusion layer according to the present invention on a semiconductor substrate, and the composition layer is formed. And subjecting the semiconductor substrate to a heat treatment. The method for manufacturing a semiconductor substrate with an n-type diffusion layer may further include other steps as necessary.
　前記半導体基板は、通常用いられる半導体基板から目的に応じて適宜選択することができる。中でもシリコン基板であることが好ましい。また前記半導体基板はｐ型半導体基板であってもｎ型半導体基板であってもよい。 The semiconductor substrate can be appropriately selected from commonly used semiconductor substrates according to the purpose. Of these, a silicon substrate is preferable. The semiconductor substrate may be a p-type semiconductor substrate or an n-type semiconductor substrate.
　半導体基板上に、本発明のｎ型拡散層形成組成物を付与する方法は特に制限されず、通常用いられる塗布方法から適宜選択して用いることができる。付与方法としては、印刷法、スピン法、刷毛塗り、スプレー法、ドクターブレード法、ロールコーター法、インクジェット法等が挙げられる。
　前記ｎ型拡散層形成組成物の付与量は特に制限されない。例えば、ドナー元素を含む化合物量として０．０１ｇ／ｍ２～１００ｇ／ｍ２とすることが好ましく、０．１ｇ／ｍ２～１０ｇ／ｍ２であることがより好ましい。 The method for applying the n-type diffusion layer forming composition of the present invention on a semiconductor substrate is not particularly limited, and can be appropriately selected from commonly used coating methods. Examples of the application method include a printing method, a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method.
The application amount of the n-type diffusion layer forming composition is not particularly limited. For example, the amount of the compound containing a donor element is preferably 0.01 g / m 2 to 100 g / m 2, and more preferably 0.1 g / m 2 to 10 g / m 2 .
　前記ｎ型拡散層形成組成物の組成によっては、半導体基板への付与後に、組成物中に含まれることがある溶剤等を揮発させるための乾燥工程を更に有することが好ましい。例えば８０℃～３００℃程度の温度で乾燥を行うことができる。乾燥時間は例えばホットプレートを使用する場合は１分～１０分、乾燥機を用いる場合は１０分～３０分程度とすることができる。この乾燥条件は、ｎ型拡散層形成組成物の溶剤組成等に応じて適宜選択でき、本発明では特に上記条件に限定されない。 Depending on the composition of the n-type diffusion layer forming composition, it is preferable to further include a drying step for volatilizing a solvent or the like that may be contained in the composition after application to the semiconductor substrate. For example, the drying can be performed at a temperature of about 80 ° C. to 300 ° C. The drying time can be, for example, about 1 to 10 minutes when using a hot plate, and about 10 to 30 minutes when using a dryer. The drying conditions can be appropriately selected according to the solvent composition of the n-type diffusion layer forming composition, and are not particularly limited to the above conditions in the present invention.
　次いで、前記組成物層が形成された半導体基板を熱処理する。熱処理の温度は例えば６００℃～１２００℃とすることができる。この熱処理により半導体基板中へドナー元素が熱拡散し、ｎ型拡散層が形成される。熱処理には公知の連続炉、バッチ炉等が適用できる。また、熱処理時の炉内雰囲気は、空気、酸素、窒素等に適宜調節することもできる。
　熱処理時間は、ｎ型拡散層形成組成物に含まれるドナー元素の含有率等に応じて適宜選択することができる。熱処理時間は例えば、１分～６０分とすることが好ましく、２分～３０分間であることがより好ましい。 Next, the semiconductor substrate on which the composition layer is formed is heat treated. The temperature of the heat treatment can be set to 600 ° C. to 1200 ° C., for example. By this heat treatment, the donor element is thermally diffused into the semiconductor substrate, and an n-type diffusion layer is formed. A known continuous furnace, batch furnace, or the like can be applied to the heat treatment. Moreover, the furnace atmosphere at the time of heat processing can also be suitably adjusted to air, oxygen, nitrogen, etc.
The heat treatment time can be appropriately selected according to the content of the donor element contained in the n-type diffusion layer forming composition. For example, the heat treatment time is preferably 1 minute to 60 minutes, and more preferably 2 minutes to 30 minutes.
　形成されたｎ型拡散層の表面には、ドナー元素を含む化合物に由来するリン酸ガラス等のガラス層が形成される場合がある。その場合はガラス層をエッチングにより除去することが好ましい。エッチング方法としては、ふっ酸等の酸に浸漬する方法、苛性ソーダ等のアルカリに浸漬する方法などの公知の方法が適用できる。 A glass layer such as phosphate glass derived from a compound containing a donor element may be formed on the surface of the formed n-type diffusion layer. In that case, it is preferable to remove the glass layer by etching. As the etching method, a known method such as a method of immersing in an acid such as hydrofluoric acid or a method of immersing in an alkali such as caustic soda can be applied.
　前記ｎ型拡散層付き半導体基板の製造方法は、半導体基板上の一部の領域に、ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物を付与して第一の組成物層を形成する工程を更に有し、前記ｎ型拡散層形成組成物層を形成する工程は、前記半導体基板上の前記第一の組成物層が形成された面と同一の面上であり、前記第一の組成物層が形成される領域とは異なる領域に、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物（特定化合物）の含有率が、前記第一のｎ型拡散層形成組成物よりも大きい前記ｎ型拡散層形成組成物を付与する工程であることが好ましい。 In the method for producing a semiconductor substrate with an n-type diffusion layer, a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium is applied to a partial region on the semiconductor substrate. And forming the n-type diffusion layer forming composition layer on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate. A metal compound (specific compound) containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in a region different from the region where the first composition layer is formed It is preferable that it is a process of providing the said n type diffused layer formation composition whose content rate is larger than said 1st n type diffused layer formation composition.
　すなわち前記ｎ型拡散層付き半導体基板の製造方法は、半導体基板上の一部の領域に、ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物を付与して第一の組成物層を形成する工程と、前記半導体基板上の前記第一の組成物層が形成される面と同一の面上であり、前記第一の組成物層が形成される領域とは異なる領域に、本発明のｎ型拡散層形成組成物であり、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が前記第一のｎ型拡散層形成組成物よりも大きい第二のｎ型拡散層形成組成物を付与して第二の組成物層を形成する工程と、前記第一の組成物層及び第二の組成物層が形成された前記半導体基板に熱処理を施す工程を有するｎ型拡散層付き半導体基板の製造方法であることが好ましい。
　これにより、同一面上にドナー元素の拡散濃度が異なる２種以上のｎ型拡散層領域が形成された半導体基板を簡便な方法で製造することができる。具体的には前記第一の組成物層が形成された領域に形成されるｎ＋型拡散層におけるドナー原子の拡散濃度よりも、前記第二の組成物層が形成された領域に形成されるｎ＋＋型拡散層におけるドナー原子の拡散濃度を高くすることができる。
　なお、第二の組成物層は、前記第一の組成物層が形成される領域とは異なる領域に加えて前記第一の組成物層上にさらに形成されてもよい。 That is, in the method for producing a semiconductor substrate with an n-type diffusion layer, a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium is applied to a partial region on the semiconductor substrate. A step of forming one composition layer, and a region on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate, wherein the first composition layer is formed. The content ratio of the metal compound containing the at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in the n-type diffusion layer forming composition of the present invention in different regions is the first n. A step of forming a second composition layer by applying a second n-type diffusion layer forming composition larger than the mold diffusion layer forming composition, and the first composition layer and the second composition layer include: With an n-type diffusion layer having a step of heat-treating the formed semiconductor substrate It is preferably a method for producing a conductive substrate.
Thereby, a semiconductor substrate in which two or more n-type diffusion layer regions having different donor element diffusion concentrations are formed on the same surface can be produced by a simple method. Specifically, it is formed in the region where the second composition layer is formed, rather than the diffusion concentration of donor atoms in the n + -type diffusion layer formed in the region where the first composition layer is formed. The diffusion concentration of donor atoms in the n ++ type diffusion layer can be increased.
The second composition layer may be further formed on the first composition layer in addition to a region different from the region where the first composition layer is formed.
＜太陽電池素子の製造方法＞
　本発明の太陽電池素子の製造方法における第一の態様は、ドナー元素を含む化合物及び分散媒を含有し、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が異なる２種以上のｎ型拡散層形成組成物を用いて、半導体基板上にドナー元素の拡散濃度が異なる２種以上の領域を形成する工程を有するものである。 <Method for producing solar cell element>
The 1st aspect in the manufacturing method of the solar cell element of this invention contains the compound and dispersion medium containing a donor element, and contains the at least 1 sort (s) of metallic element chosen from the group which consists of an alkaline-earth metal and an alkali metal. The method includes forming two or more regions having different donor element diffusion concentrations on a semiconductor substrate using two or more types of n-type diffusion layer forming compositions having different metal compound contents.
　具体的には、半導体基板上の一部の領域に、ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物を付与して第一の組成物層を形成する工程と、前記半導体基板上の前記第一の組成物層が形成される面と同一の面上であり、前記第一の組成物層が形成される領域とは異なる領域に、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物（特定化合物）の含有率が前記第一のｎ型拡散層形成組成物よりも大きい第二のｎ型拡散層形成組成物を付与して第二の組成物層を形成する工程と、前記第一の組成物層及び第二の組成物層が形成された前記半導体基板に熱処理を施して、前記半導体基板上の前記第二の組成物層が形成された領域にｎ＋型拡散層を、前記第一の組成物層が形成された領域に前記ｎ＋型拡散層よりも小さい表面シート抵抗値を有するｎ＋＋型拡散層をそれぞれ形成する工程と、前記ｎ＋＋型拡散層上に、電極を形成する工程とを有する太陽電池素子の製造方法である。 Specifically, a step of forming a first composition layer by applying a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium to a partial region on a semiconductor substrate And an alkaline earth metal and a region different from a region where the first composition layer is formed on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate. Second n-type diffusion layer forming composition in which the content of the metal compound (specific compound) containing at least one metal element selected from the group consisting of alkali metals is larger than that of the first n-type diffusion layer forming composition Applying a product to form a second composition layer, and applying heat treatment to the semiconductor substrate on which the first composition layer and the second composition layer are formed, An n + -type diffusion layer is formed in the region where the second composition layer is formed, Forming n ++ type diffusion layer having a small surface sheet resistance than the n + -type diffusion layer formed product layer formed regions respectively, the n ++ type diffusion layer, forming an electrode The manufacturing method of the solar cell element which has these.
　前記第一のｎ型拡散層形成組成物及び第二のｎ型拡散層形成組成物における特定化合物の含有率は、前記第二のｎ型拡散層形成組成物中の方が前記第一のｎ型拡散層形成組成物中よりも大きい限り特に制限されない。前記第一のｎ型拡散層形成組成物中における特定化合物の含有率が１０質量％以下であり、前記第二のｎ型拡散層形成組成物中における特定化合物の含有率が０．０１質量％以上５０質量％以下であることが好ましく、前記第一のｎ型拡散層形成組成物中における特定化合物の含有率が１質量％以下であり、前記第二のｎ型拡散層形成組成物中における特定化合物の含有率が０．０１質量％以上５０質量％以下であることがより好ましく、前記第一のｎ型拡散層形成組成物中における特定化合物の含有率が０．１質量％以下であり、前記第二のｎ型拡散層形成組成物中における特定化合物の含有率が０．５質量％以上３０質量％以下であることがさらに好ましい。 The content ratio of the specific compound in the first n-type diffusion layer forming composition and the second n-type diffusion layer forming composition is higher in the first n-type diffusion layer forming composition than in the first n. As long as it is larger than in the mold diffusion layer forming composition, it is not particularly limited. The content of the specific compound in the first n-type diffusion layer forming composition is 10% by mass or less, and the content of the specific compound in the second n-type diffusion layer forming composition is 0.01% by mass. It is preferable that it is 50 mass% or less, the content rate of the specific compound in said 1st n type diffused layer formation composition is 1 mass% or less, and in said 2nd n type diffused layer formation composition More preferably, the content of the specific compound is 0.01% by mass or more and 50% by mass or less, and the content of the specific compound in the first n-type diffusion layer forming composition is 0.1% by mass or less. More preferably, the content of the specific compound in the second n-type diffusion layer forming composition is 0.5% by mass or more and 30% by mass or less.
　前記製造方法で形成されるｎ＋＋型拡散層及びｎ＋型拡散層におけるドナー元素の拡散濃度は特に制限されず、目的に応じて適宜選択することができる。例えば、ｎ＋＋型拡散層の表面におけるシート抵抗値が１０Ω／□以上８０Ω／□以下であり、ｎ＋型拡散層の表面におけるシート抵抗値がｎ＋＋型拡散層の表面におけるシート抵抗値よりも大きく、６０Ω／□以上１５０Ω／□以下となるようにすることが好ましく、ｎ＋＋型拡散層の表面におけるシート抵抗値が１０Ω／□以上７０Ω／□未満であり、ｎ＋型拡散層の表面におけるシート抵抗値が７０Ω／□以上１５０Ω／□以下となることがより好ましく、ｎ＋＋型拡散層の表面におけるシート抵抗値が３０Ω／□以上６０Ω／□以下であり、ｎ＋型拡散層の表面におけるシート抵抗値が８０Ω／□以上１２０Ω／□以下となることがさらに好ましい。
　なお、半導体基板の表面におけるシート抵抗値は、通常用いられる四探針法により測定される。四探針法は、例えば三菱化学（株）製Ｌｏｒｅｓｔａ－ＥＰ　ＭＣＰ－Ｔ３６０型低抵抗率計を用いて行うことができる。 The diffusion concentration of the donor element in the n ++ type diffusion layer and the n + type diffusion layer formed by the manufacturing method is not particularly limited, and can be appropriately selected according to the purpose. For example, 80 [Omega / □ or less the sheet resistance of 10 [Omega / □ or more in the surface of the n ++ type diffusion layer, than the sheet resistance value at the surface of the sheet resistance n ++ type diffusion layer in the surface of the n + -type diffusion layer The sheet resistance value on the surface of the n ++ type diffusion layer is 10 Ω / □ or more and less than 70 Ω / □, and it is preferably on the surface of the n + type diffusion layer. It is more preferable that the sheet resistance value is 70Ω / □ or more and 150Ω / □ or less, the sheet resistance value on the surface of the n ++ type diffusion layer is 30Ω / □ or more and 60Ω / □ or less, and on the surface of the n ++ type diffusion layer. It is more preferable that the sheet resistance value is 80Ω / □ or more and 120Ω / □ or less.
The sheet resistance value on the surface of the semiconductor substrate is measured by a commonly used four-point probe method. The four-probe method can be performed using, for example, a Loresta-EP MCP-T360 type low resistivity meter manufactured by Mitsubishi Chemical Corporation.
　半導体基板上に、前記第一及び第二のｎ型拡散層形成組成物を付与してそれぞれ形成される第一及び第二の組成物層の形状は特に制限されず、目的に応じて適宜選択される。例えば第一の組成物層を、電極が形成される領域に対応する領域に形成し、第二の組成物層を少なくとも電極が形成される領域以外の領域に形成することが好ましい。また第一の組成物層を、電極が形成される領域に対応する領域に形成した後、第二の組成物層を第一の組成物層が形成された領域を含む半導体基板面の全面に形成してもよい。このように第一及び第二の組成物層を形成することで選択エミッタ構造を有する太陽電池素子を効率的に製造することができる。 The shapes of the first and second composition layers formed by applying the first and second n-type diffusion layer forming compositions on the semiconductor substrate are not particularly limited and are appropriately selected according to the purpose. Is done. For example, it is preferable that the first composition layer is formed in a region corresponding to the region where the electrode is formed, and the second composition layer is formed at least in a region other than the region where the electrode is formed. Further, after forming the first composition layer in a region corresponding to the region where the electrode is formed, the second composition layer is formed on the entire surface of the semiconductor substrate including the region where the first composition layer is formed. It may be formed. Thus, the solar cell element which has a selective emitter structure can be efficiently manufactured by forming the 1st and 2nd composition layer.
　第一及び第二のｎ型拡散層形成組成物を付与方法及び熱処理の詳細は既述の通りであり、好ましい態様も同様である。 Details of the method for applying the first and second n-type diffusion layer forming compositions and the heat treatment are as described above, and the preferred embodiments are also the same.
　次いで、熱拡散処理によって形成されたｎ＋＋型拡散層上に電極を形成する。電極の形成方法は特に制限されず、通常用いられる電極形成方法から適宜選択することができる。例えば市販の銀ペーストを用いる電極形成方法を適用することができる。 Next, an electrode is formed on the n ++ type diffusion layer formed by thermal diffusion treatment. The electrode formation method is not particularly limited, and can be appropriately selected from commonly used electrode formation methods. For example, an electrode forming method using a commercially available silver paste can be applied.
　前記太陽電池素子の製造方法は、半導体基板上のｐ型拡散層上に電極を形成する工程をさらに含むことが好ましい。ｐ型拡散層上に電極を形成する方法は特に制限されず、通常用いられる電極形成方法から適宜選択することができる。例えば市販のアルミペーストを用いる電極形成方法を適用することができる。 Preferably, the method for manufacturing the solar cell element further includes a step of forming an electrode on the p-type diffusion layer on the semiconductor substrate. The method for forming the electrode on the p-type diffusion layer is not particularly limited, and can be appropriately selected from commonly used electrode forming methods. For example, an electrode forming method using a commercially available aluminum paste can be applied.
　本発明の太陽電池素子の製造方法における第二の態様は、半導体基板上に、ドナー元素を含む化合物、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物、及び分散媒を含有するｎ型拡散層形成組成物の少なくとも１種を付与してｎ型拡散層形成組成物層を形成する工程と、前記ｎ型拡散層形成組成物層が形成された半導体基板に熱処理を施して、ｎ型拡散層を形成する工程と、形成されたｎ型拡散層上に電極を形成する工程とを有する太陽電池素子の製造方法である。 The second aspect of the method for producing a solar cell element of the present invention is a metal containing at least one metal element selected from the group consisting of a compound containing a donor element, an alkaline earth metal, and an alkali metal on a semiconductor substrate. A step of forming an n-type diffusion layer forming composition layer by applying at least one kind of an n-type diffusion layer forming composition containing a compound and a dispersion medium, and the n-type diffusion layer forming composition layer was formed A method for manufacturing a solar cell element, comprising: a step of forming a n-type diffusion layer by performing a heat treatment on a semiconductor substrate; and a step of forming an electrode on the formed n-type diffusion layer.
　前記第二の態様の製造方法は、ｎ型拡散層を形成する工程の前に、半導体基板上のｎ型拡散層形成組成物層が形成される面と同一の面上に、アクセプター元素を含む化合物、及び分散媒を含有するｐ型拡散層形成組成物を付与してｐ型拡散層形成組成物層を形成する工程を更に含むことが好ましい。これにより例えば、バックコンタクト型の太陽電池素子を効率よく製造することができる。
　前記太陽電池素子の製造方法で製造される太陽電池素子の形状及び大きさに制限はない。例えば、一辺が１２５ｍｍ～１５６ｍｍの正方形であることが好ましい。 The manufacturing method of the second aspect includes an acceptor element on the same surface as the surface on which the n-type diffusion layer forming composition layer is formed on the semiconductor substrate before the step of forming the n-type diffusion layer. It is preferable to further include a step of forming a p-type diffusion layer forming composition layer by applying a p-type diffusion layer forming composition containing a compound and a dispersion medium. Thereby, for example, a back contact type solar cell element can be efficiently manufactured.
There is no restriction | limiting in the shape and magnitude | size of the solar cell element manufactured with the manufacturing method of the said solar cell element. For example, a square having a side of 125 mm to 156 mm is preferable.
＜太陽電池＞
　前記太陽電池素子の製造方法で製造された太陽電池素子は、太陽電池の製造に用いられる。太陽電池は、前記製造方法で製造された太陽電池素子の少なくとも１種を含み、太陽電池素子の電極上に配線材料（タブ線等）が配置されて構成される。太陽電池はさらに必要に応じて、配線材料を介して複数の太陽電池素子が連結され、さらに封止材で封止されて構成されていてもよい。
　前記配線材料及び封止材としては特に制限されず、当業界で通常用いられているものから適宜選択することができる。
　太陽電池の形状及び大きさに特に制限はない。例えば、０．５ｍ２～３ｍ２であることが好ましい。 <Solar cell>
The solar cell element manufactured by the method for manufacturing a solar cell element is used for manufacturing a solar cell. The solar cell includes at least one type of solar cell element manufactured by the above manufacturing method, and is configured by arranging a wiring material (such as a tab wire) on the electrode of the solar cell element. If necessary, the solar cell may be constituted by connecting a plurality of solar cell elements via a wiring material and further sealing with a sealing material.
The wiring material and the sealing material are not particularly limited, and can be appropriately selected from those usually used in the industry.
There is no particular limitation on the shape and size of the solar cell. For example, it is preferably 0.5 m 2 to 3 m 2 .
　次に本発明のｎ型拡散層付き半導体基板及び太陽電池素子の製造方法について、図面を参照しながら説明する。図１は、本実施形態にかかる太陽電池素子の製造工程の一例を概念的に表す模式断面図である。以降の図面においては、共通する構成要素に同じ符号を付す。また、図面に示される各構成要素の大きさは一例であり、各構成要素間における大きさの相対的な関係を制限するものではない。 Next, a method for manufacturing a semiconductor substrate with an n-type diffusion layer and a solar cell element according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view conceptually showing an example of the manufacturing process of the solar cell element according to the present embodiment. In the subsequent drawings, common constituent elements are denoted by the same reference numerals. The size of each component shown in the drawings is an example, and does not limit the relative size relationship between the components.
　図１（１）では、ｐ型半導体基板１０である結晶シリコン基板にアルカリ溶液を付与してダメージ層を除去し、テクスチャ構造（図中ではテクスチャ構造の記載を省略する）をエッチングにて得る。
　詳細には、インゴットからスライスした際に発生するシリコン表面のダメージ層を２０質量％苛性ソーダで除去する。次いで１質量％苛性ソーダと１０質量％イソプロピルアルコールの混合液によりエッチングを行い、テクスチャ構造を形成する。太陽電池素子は、受光面（以下、「おもて面」ともいう）側にテクスチャ構造を形成することにより、光閉じ込め効果が促され、高効率化が図られる。 In FIG. 1A, an alkaline solution is applied to a crystalline silicon substrate which is a p-type semiconductor substrate 10 to remove a damaged layer, and a texture structure (the description of the texture structure is omitted in the figure) is obtained by etching.
Specifically, the damaged layer on the silicon surface generated when slicing from the ingot is removed with 20% by mass caustic soda. Next, etching is performed with a mixed solution of 1% by mass caustic soda and 10% by mass isopropyl alcohol to form a texture structure. In the solar cell element, by forming a texture structure on the light receiving surface (hereinafter also referred to as “front surface”) side, a light confinement effect is promoted and high efficiency is achieved.
　図１（２）では、ｐ型半導体基板１０の受光面となる面に、上記第一のｎ型拡散層形成組成物を付与して、第一の組成物層１１を形成する。本発明では、付与方法には制限がない。付与方法には例えば、印刷法、スピン法、刷毛塗り、スプレー法、ドクターブレード法、ロールコーター法、及びインクジェット法が挙げられる。
　上記第一のｎ型拡散層形成組成物の塗布量としては特に制限はない。例えば、ガラス粉末量として０．０１ｇ／ｍ２～１００ｇ／ｍ２とすることが好ましく、０．１ｇ／ｍ２～１０ｇ／ｍ２であることがより好ましい。 In FIG. 1B, the first composition layer 11 is formed by applying the first n-type diffusion layer forming composition to the surface that becomes the light receiving surface of the p-type semiconductor substrate 10. In the present invention, there is no limitation on the application method. Examples of the application method include a printing method, a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method.
There is no restriction | limiting in particular as an application quantity of said 1st n type diffused layer formation composition. For example, the amount of glass powder is preferably 0.01 g / m 2 to 100 g / m 2, and more preferably 0.1 g / m 2 to 10 g / m 2 .
　なお、第一のｎ型拡散層形成組成物の組成によっては、塗布後に、組成物中に含まれる溶剤を揮発させるための乾燥工程を設けることが好ましい。この場合には、８０℃～３００℃程度の温度で乾燥することができる。乾燥時間は例えばホットプレート等を使用する場合は１分～１０分、乾燥機等を用いる場合は１０分～３０分程度とすることができる。この乾燥条件は、ｎ型拡散層形成組成物の溶剤組成に依存しており、本発明では特に上記条件に限定されない。 Depending on the composition of the first n-type diffusion layer forming composition, it is preferable to provide a drying step for volatilizing the solvent contained in the composition after coating. In this case, drying can be performed at a temperature of about 80 ° C. to 300 ° C. For example, the drying time can be about 1 to 10 minutes when using a hot plate or the like, and about 10 to 30 minutes when using a dryer or the like. The drying conditions depend on the solvent composition of the n-type diffusion layer forming composition, and are not particularly limited to the above conditions in the present invention.
　次いで、前記第一の組成物層１１の上を含む受光面全面に第二のｎ型拡散層形成組成物を付与して、第二の組成物層１２を形成する。この際、第二のｎ型拡散層形成組成物に含まれるアルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物（特定化合物）の濃度は、前記第一のｎ型拡散層形成組成物に含まれる特定化合物の濃度よりも相対的に高い。これにより各ｎ型拡散層形成組成物の拡散能を制御できる。 Next, a second n-type diffusion layer forming composition is applied to the entire light receiving surface including the first composition layer 11 to form the second composition layer 12. At this time, the concentration of the metal compound (specific compound) containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals contained in the second n-type diffusion layer forming composition is It is relatively higher than the concentration of the specific compound contained in one n-type diffusion layer forming composition. Thereby, the diffusivity of each n type diffused layer formation composition is controllable.
　具体的には、特定化合物を１０質量％以下、好ましくは含まない第一のｎ型拡散層形成組成物を付与する。次いで、受光面全面に特定化合物を０．０１質量％以上５０質量％以下含み、第一のｎ型拡散層形成組成物よりも特定化合物の濃度が高い第二のｎ型拡散層形成組成物を付与することが好ましい。
　なお、前記第一の組成物層１１の上に第二の組成物層１２を形成せずに、前記第一の組成物層以外の受光面の領域に第二の組成物層１２を形成してもよい。 Specifically, the first n-type diffusion layer forming composition containing 10% by mass or less, preferably not containing the specific compound is applied. Next, a second n-type diffusion layer forming composition containing 0.01% to 50% by weight of the specific compound on the entire light-receiving surface and having a higher concentration of the specific compound than the first n-type diffusion layer forming composition It is preferable to give.
In addition, without forming the second composition layer 12 on the first composition layer 11, the second composition layer 12 is formed in the region of the light receiving surface other than the first composition layer. May be.
　次いで、上記第一の組成物層１１及び第二の組成物層１２を形成した半導体基板１０を、熱処理する。熱処理の温度は特に制限はないが、６００℃～１２００℃であることが好ましく、７５０℃～１０５０℃であることがより好ましい。また、熱処理の時間は特に制限はない。例えば、１分～３０分間で行なうことが好ましい。この熱処理により、図１（３）に示すように半導体基板中へドナー元素が拡散し、ｎ＋＋型拡散層１３及びｎ＋型拡散層１４がそれぞれ形成される。熱処理には公知の連続炉、バッチ炉等が適用できる。また、熱処理時の炉内雰囲気は、空気、酸素、窒素等に適宜調節することもできる。
　熱処理時間は、前記第一及び第二のｎ型拡散層形成組成物に含まれるドナー元素の含有率等に応じて適宜選択することができる。例えば、１分～６０分間とすることができ、２分～３０分間であることがより好ましい。 Next, the semiconductor substrate 10 on which the first composition layer 11 and the second composition layer 12 are formed is heat-treated. The temperature of the heat treatment is not particularly limited, but is preferably 600 ° C. to 1200 ° C., more preferably 750 ° C. to 1050 ° C. Further, the heat treatment time is not particularly limited. For example, it is preferably performed for 1 to 30 minutes. By this heat treatment, the donor element diffuses into the semiconductor substrate as shown in FIG. 1 (3), and an n ++ type diffusion layer 13 and an n + type diffusion layer 14 are formed. A known continuous furnace, batch furnace, or the like can be applied to the heat treatment. Moreover, the furnace atmosphere at the time of heat processing can also be suitably adjusted to air, oxygen, nitrogen, etc.
The heat treatment time can be appropriately selected according to the content of the donor element contained in the first and second n-type diffusion layer forming compositions. For example, it can be 1 minute to 60 minutes, more preferably 2 minutes to 30 minutes.
　形成されたｎ＋＋型拡散層１３及びｎ＋型拡散層１４ではドナー元素の拡散濃度に差が生じている。具体的には、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくともの金属元素を含有する金属化合物を多く含む第二のｎ型拡散層形成組成物によって形成されたｎ＋型拡散層１４は、第一のｎ型拡散層形成組成物によって形成されたｎ＋＋型拡散層１３よりもドナー元素の拡散濃度が小さい。 In the formed n ++ type diffusion layer 13 and the n + type diffusion layer 14, there is a difference in the diffusion concentration of the donor element. Specifically, the n + -type diffusion layer 14 formed by the second n-type diffusion layer forming composition containing a large amount of a metal compound containing at least a metal element selected from the group consisting of alkaline earth metals and alkali metals. Has a lower donor element diffusion concentration than the n ++ type diffusion layer 13 formed by the first n-type diffusion layer forming composition.
　従来、ｎ型拡散層を形成する方法としては、オキシ塩化リンガス等を用いる熱拡散処理があった。その場合、ドナー元素の拡散濃度の異なる２種以上のｎ型拡散層を形成するには、熱拡散処理とマスク処理とを複数回組み合わせる必要があった。さらに塩化リンは毒物であるため、オキシ塩化リンガスによる処理を行ったあと、不活性ガスで１時間程度置換する必要があり、ｎ型拡散層が形成された半導体基板を取り出してすぐに次の工程に移すことはできないという課題もあった。しかし、第一及び第二のｎ型拡散層形成組成物を用いてｎ＋＋型拡散層１３及びｎ＋型拡散層１４を形成すると、前記のようにドナー元素の拡散濃度の異なる２種以上のｎ型拡散層が、簡便な方法で所望の領域に選択的にそれぞれ形成されるため、効率的に選択エミッタ構造を有する太陽電池素子を製造することができる。 Conventionally, as a method of forming an n-type diffusion layer, there has been a thermal diffusion treatment using phosphorus oxychloride gas or the like. In that case, in order to form two or more types of n-type diffusion layers having different donor element diffusion concentrations, it is necessary to combine thermal diffusion treatment and mask treatment multiple times. Furthermore, since phosphorus chloride is a poisonous substance, it must be replaced with an inert gas for about 1 hour after being treated with phosphorus oxychloride gas. The next step is immediately after taking out the semiconductor substrate on which the n-type diffusion layer is formed. There was also a problem that it could not be transferred to. However, when the n ++ type diffusion layer 13 and the n + type diffusion layer 14 are formed using the first and second n-type diffusion layer forming compositions, as described above, two or more kinds having different diffusion concentrations of the donor element are used. Since the n-type diffusion layer is selectively formed in a desired region by a simple method, a solar cell element having a selective emitter structure can be manufactured efficiently.
　熱処理によって形成されたｎ＋＋型拡散層１３の表面には第一のｎ型拡散層形成組成物の熱処理物層１１Ａが、ｎ＋型拡散層１４の表面には第二のｎ型拡散層形成組成物の熱処理物層１２Ａがそれぞれ形成される。これら熱処理物層においてはリン酸ガラス等のガラス層が形成されているため、このリン酸ガラスをエッチング処理により除去する。エッチング方法としては、ふっ酸等の酸に浸漬する方法、苛性ソーダ等のアルカリに浸漬する方法など公知の方法が適用できる。エッチング処理により、図１（５）に示すようにドナー元素の拡散濃度の異なるｎ＋＋型拡散層１３及びｎ＋型拡散層１４という２種類のｎ型拡散層を容易に作ることができる。 The heat-treated product layer 11A of the first n-type diffusion layer forming composition is formed on the surface of the n ++ -type diffusion layer 13 formed by the heat treatment, and the second n-type diffusion layer is formed on the surface of the n + -type diffusion layer 14. A heat treatment product layer 12A of the composition is formed. Since a glass layer such as phosphate glass is formed in these heat-treated layers, the phosphate glass is removed by an etching process. As an etching method, a known method such as a method of immersing in an acid such as hydrofluoric acid or a method of immersing in an alkali such as caustic soda can be applied. By etching, two types of n-type diffusion layers, n ++ -type diffusion layer 13 and n + -type diffusion layer 14 having different donor element diffusion concentrations, can be easily formed as shown in FIG.
　このように第一及び第二のｎ型拡散層形成組成物を用いることで、一度の熱処理により、ドナー元素の拡散濃度の異なる２種類のｎ型拡散層を簡便に形成することができる。ここではドナー元素の拡散濃度の異なる２種類のｎ型拡散層を形成する例を示したが、特定化合物の含有量が異なる３種類以上のｎ型拡散層形成組成物を調製し、これらを選択的に所望の領域に付与することで、ドナー元素の拡散濃度の異なる３種類以上のｎ型拡散層を容易に形成することもできる。 Thus, by using the first and second n-type diffusion layer forming compositions, two types of n-type diffusion layers having different donor element diffusion concentrations can be easily formed by a single heat treatment. In this example, two types of n-type diffusion layers with different donor element diffusion concentrations were formed. However, three or more types of n-type diffusion layer forming compositions with different specific compound contents were prepared and selected. In particular, by providing the desired region, it is possible to easily form three or more types of n-type diffusion layers having different donor element diffusion concentrations.
　次いで図１（６）に示すように、ｎ＋＋型拡散層１３及びｎ＋型拡散層１４の上に反射防止膜１５を形成する。反射防止膜１５は公知の技術を適用して形成される。例えば、反射防止膜１５が窒化ケイ素膜の場合には、ＳｉＨ４とＮＨ３の混合ガスを原料とするプラズマＣＶＤ法により形成する。このとき、水素が結晶中に拡散し、シリコン原子の結合に寄与しない軌道、即ちダングリングボンドと水素が結合し、欠陥を不活性化（水素パッシベーション）する。より具体的には、上記混合ガスの流量比ＮＨ３／ＳｉＨ４が０．０５～１．０、反応室の圧力が０．１Ｔｏｒｒ（１３．３Ｐａ）～２Ｔｏｒｒ（２６６．６Ｐａ）、成膜時の温度が３００℃～５５０℃、プラズマの放電のための周波数が１００ｋＨｚ以上の条件下で形成される。反射防止膜の膜厚に特に制限はない。例えば、１０ｎｍ～３００ｎｍとすることが好ましく、３０ｎｍ～１５０ｎｍとすることがより好ましい。 Next, as shown in FIG. 1 (6), an antireflection film 15 on the n ++ type diffusion layer 13 and the n + -type diffusion layer 14. The antireflection film 15 is formed by applying a known technique. For example, when the antireflection film 15 is a silicon nitride film, it is formed by a plasma CVD method using a mixed gas of SiH 4 and NH 3 as a raw material. At this time, hydrogen diffuses into the crystal, and orbits that do not contribute to the bonding of silicon atoms, that is, dangling bonds and hydrogen are combined to inactivate defects (hydrogen passivation). More specifically, the flow rate ratio NH 3 / SiH 4 of the mixed gas is 0.05 to 1.0, the pressure in the reaction chamber is 0.1 Torr (13.3 Pa) to 2 Torr (266.6 Pa), and during film formation The film is formed under the conditions of a temperature of 300 ° C. to 550 ° C. and a frequency for plasma discharge of 100 kHz or more. There is no particular limitation on the thickness of the antireflection film. For example, the thickness is preferably 10 nm to 300 nm, and more preferably 30 nm to 150 nm.
　図１（７）に示すように、受光面のｎ＋＋型拡散層１３の領域上に形成された反射防止膜１５上に、表面電極用金属ペーストをスクリーン印刷法等で付与し乾燥することで、表面電極用金属ペースト層１６Ａを形成する。表面電極用金属ペーストは、（１）金属粒子と（２）ガラス粒子とを必須成分とし、必要に応じて（３）樹脂バインダ、（４）その他の添加剤等を含む。 As shown in FIG. 1 (7), a surface electrode metal paste is applied by screen printing or the like on the antireflection film 15 formed on the n ++ type diffusion layer 13 region of the light receiving surface and dried. Then, the surface electrode metal paste layer 16A is formed. The metal paste for a surface electrode includes (1) metal particles and (2) glass particles as essential components, and includes (3) a resin binder, (4) other additives, and the like as necessary.
　次いで、裏面側に裏面電極用金属ペースト層１７Ａを形成する。本発明では裏面電極１７の材質及び形成方法は特に限定されない。例えば、アルミニウム、銀、銅等の金属を含む裏面電極用金属ペーストを付与し、乾燥させて、裏面電極用金属ペースト層１７Ａを形成してもよい。
　一般的にはアルミニウムを含む裏面電極用金属ペーストを用いて、裏面電極用金属ペースト層１７Ａを形成し、これを焼成処理することで裏面電極１７を形成すると同時に裏面にｐ＋型拡散層（高濃度電界層）１８を形成する。このとき裏面に、モジュール工程における太陽電池素子間の接続のために、一部に銀電極形成用銀ペーストを設けてもよい。 Next, a back electrode metal paste layer 17A is formed on the back side. In the present invention, the material and forming method of the back electrode 17 are not particularly limited. For example, the back electrode metal paste layer 17 </ b> A may be formed by applying a metal paste for the back electrode including a metal such as aluminum, silver, or copper and drying the paste.
In general, a back electrode metal paste layer 17A is formed using a back electrode metal paste containing aluminum, and this is fired to form the back electrode 17, and at the same time, a p + -type diffusion layer (high Concentration electric field layer) 18 is formed. At this time, a silver electrode forming silver paste may be provided on a part of the rear surface for connection between solar cell elements in the module process.
　本発明の製造方法を用いる場合、裏面のｐ＋型拡散層（高濃度電界層）１８の製造方法はアルミニウムを含む裏面電極用金属ペーストによる方法に限定されることなく、従来公知のいずれの方法も採用でき、製造方法の選択肢が広がる。例えば、Ｂ（ボロン）等の第１３族の元素を含むｐ型拡散層形成組成物を付与し、ｐ＋型拡散層１８を形成することができる。
　また裏面の表面電極１７の厚さも従来のものよりも薄く形成することが可能となる。 When using the manufacturing method of the present invention, the manufacturing method of the p + -type diffusion layer (high concentration electric field layer) 18 on the back surface is not limited to the method using the metal paste for the back electrode containing aluminum, and any conventionally known method is used. Can be adopted, and the choice of manufacturing method is expanded. For example, the p + -type diffusion layer 18 can be formed by applying a p-type diffusion layer forming composition containing a Group 13 element such as B (boron).
In addition, the thickness of the front surface electrode 17 on the back surface can be made thinner than the conventional one.
　表面電極用金属ペースト層１６Ａ及び裏面電極用金属ペースト層１７Ａが形成された半導体基板を焼成処理し、図１（８）に示すように表面電極１６及び裏面電極１７を形成して、太陽電池素子を完成させる。焼成処理は例えば、６００℃～９００℃の範囲で数秒～数分間とすることができる。このとき表面側では表面電極用金属ペースト層１６Ａに含まれるガラス粒子によって絶縁膜である反射防止膜１５が溶融し、更にｐ型半導体基板１０表面も一部溶融して、ペースト中の金属粒子（例えば銀粒子）がｐ型半導体基板１０のｎ＋＋型拡散層１３と接触部を形成し凝固する。これにより表面電極１６とｐ型半導体基板１０とが導通される。これはファイアースルーと称されている。また、裏面側にアルミニウムを含む裏面電極用金属ペースト層１７Ａを形成した場合には、裏面電極１７が形成される際にアルミニウムがｐ型半導体基板１０へ拡散したｐ＋型拡散層１８が形成され、Back Surface Fieldと呼ばれる裏面電界効果が発現し、高効率化に寄与する。 The semiconductor substrate on which the front electrode metal paste layer 16A and the back electrode metal paste layer 17A are formed is baked to form the front electrode 16 and the back electrode 17 as shown in FIG. To complete. For example, the baking treatment can be performed in the range of 600 ° C. to 900 ° C. for several seconds to several minutes. At this time, on the surface side, the antireflection film 15 that is an insulating film is melted by the glass particles contained in the metal paste layer 16A for the surface electrode, and the surface of the p-type semiconductor substrate 10 is also partially melted, so that the metal particles ( For example, silver particles) form a contact portion with the n ++ type diffusion layer 13 of the p-type semiconductor substrate 10 and solidify. Thereby, the surface electrode 16 and the p-type semiconductor substrate 10 are electrically connected. This is called fire-through. Further, when the back electrode metal paste layer 17A containing aluminum is formed on the back surface side, when the back electrode 17 is formed, a p + type diffusion layer 18 in which aluminum diffuses into the p type semiconductor substrate 10 is formed. The back surface field effect called Back Surface Field appears and contributes to high efficiency.
　次に表面電極１６の形状について説明する。表面電極１６は、図２（Ａ）及び図２（Ｂ）に示すように、バスバー電極３０、及び該バスバー電極３０と交差しているフィンガー電極３２で構成される。図２（Ａ）は、表面電極１６を、バスバー電極３０、及び該バスバー電極３０と交差しているフィンガー電極３２からなる構成とした太陽電池素子を受光面（表面）から見た平面図であり、図２（Ｂ）は、図２（Ａ）の一部を拡大して示す斜視図である。 Next, the shape of the surface electrode 16 will be described. As shown in FIGS. 2A and 2B, the surface electrode 16 includes a bus bar electrode 30 and finger electrodes 32 intersecting with the bus bar electrode 30. FIG. 2A is a plan view of a solar cell element in which the surface electrode 16 includes a bus bar electrode 30 and a finger electrode 32 intersecting the bus bar electrode 30 as viewed from the light receiving surface (front surface). FIG. 2B is an enlarged perspective view showing a part of FIG.
　このような表面電極１６は、例えば、上述したように金属ペーストをスクリーン印刷等で付与し、これを焼成処理することで形成することができる。また電極材料のメッキ、高真空中における電子ビーム加熱による電極材料の蒸着等の手段により形成することができる。バスバー電極３０とフィンガー電極３２とからなる表面電極１６は受光面側の電極として一般的に用いられていて周知であり、受光面側のバスバー電極及びフィンガー電極の公知の形成手段を適用することができる。 Such a surface electrode 16 can be formed, for example, by applying a metal paste by screen printing or the like as described above and baking it. Further, it can be formed by means such as plating of electrode material, vapor deposition of electrode material by electron beam heating in high vacuum. The surface electrode 16 composed of the bus bar electrode 30 and the finger electrode 32 is generally used as an electrode on the light receiving surface side and is well known, and known forming means for the bus bar electrode and finger electrode on the light receiving surface side can be applied. it can.
　上記では、表面にｎ＋＋型拡散層１３及びｎ＋型拡散層１４、裏面にｐ＋型拡散層１８を形成し、更にｎ＋＋型拡散層１３及びｐ＋型拡散層１８の上にそれぞれ表面電極１６及び裏面電極１７を設けた太陽電池素子について説明した。一方、本発明のｎ型拡散層形成組成物を用いればバックコンタクト型の太陽電池素子を簡便に作製することも可能である。
　バックコンタクト型の太陽電池素子は、電極を全て裏面に設けて受光面の面積を大きくするものである。つまりバックコンタクト型の太陽電池素子では、裏面にｎ＋型拡散層部位及びｐ＋型拡散層部位の両方を形成してｐｎ接合構造とする必要がある。本発明のｎ型拡散層形成組成物は、特定の部位にのみｎ＋型拡散層部位を形成することが可能であり、よってバックコンタクト型の太陽電池素子の製造に好適に適用することができる。 In the above, the n ++ type diffusion layer 13 and the n + type diffusion layer 14 are formed on the front surface, the p + type diffusion layer 18 is formed on the back surface, and the surface is further formed on the n ++ type diffusion layer 13 and the p + type diffusion layer 18, respectively. The solar cell element provided with the electrode 16 and the back electrode 17 has been described. On the other hand, if the composition for forming an n-type diffusion layer of the present invention is used, a back contact solar cell element can be easily produced.
The back contact type solar cell element has all electrodes provided on the back surface to increase the area of the light receiving surface. That is, in the back contact type solar cell element, it is necessary to form both the n + type diffusion layer part and the p + type diffusion layer part on the back surface to form a pn junction structure. The n-type diffusion layer forming composition of the present invention can form an n + -type diffusion layer portion only at a specific portion, and thus can be suitably applied to the production of a back contact type solar cell element. .
　裏面にｎ＋型拡散層部位及びｐ＋型拡散層部位の両方を形成する場合、リン等のドナー元素を含むｎ型拡散層形成組成物及びホウ素等のアクセプター元素を含むｐ型拡散層形成組成物を用い、これらを所望の領域にそれぞれ付与し、熱処理することでｎ＋型拡散層部位及びｐ＋型拡散層部位をそれぞれ形成することができる。 In the case where both the n + type diffusion layer part and the p + type diffusion layer part are formed on the back surface, an n type diffusion layer forming composition containing a donor element such as phosphorus and a p type diffusion layer forming composition containing an acceptor element such as boron An n + -type diffusion layer region and a p + -type diffusion layer region can be formed by applying an object to each desired region and performing heat treatment.
　ここで一般的にリン等のドナー元素の拡散の方が、ホウ素等のアクセプター元素の拡散よりも容易である。従って同じ拡散温度で同時に熱処理すると、ｎ＋型拡散層部位のシート抵抗の方が、ｐ＋型拡散部位のシート抵抗よりも小さくなりすぎる傾向があった。本発明のｎ型拡散層形成組成物は、特定化合物を含むことでドナー元素の拡散性を調節することができるため、ｎ型拡散層形成組成物による半導体基板への拡散濃度を調節することができる。これにより、ｎ＋型拡散層部位とｐ＋型拡散層部位を同時に形成することができ、プロセス時間を短縮することができる。 Here, diffusion of a donor element such as phosphorus is generally easier than diffusion of an acceptor element such as boron. Therefore, when heat treatment is simultaneously performed at the same diffusion temperature, the sheet resistance of the n + type diffusion layer portion tends to be too small than the sheet resistance of the p + type diffusion region. Since the n-type diffusion layer forming composition of the present invention can adjust the diffusibility of the donor element by containing the specific compound, the diffusion concentration of the n-type diffusion layer forming composition into the semiconductor substrate can be adjusted. it can. Thereby, the n + -type diffusion layer portion and the p + -type diffusion layer portion can be formed at the same time, and the process time can be shortened.
　具体的には、例えば図３にその一例の概略を示すような製造工程を含む製造方法で、バックコンタクト型の太陽電池素子を製造することができる。 Specifically, for example, a back contact solar cell element can be manufactured by a manufacturing method including a manufacturing process as schematically shown in FIG.
　はじめに図３（１）に示すように、ｎ型半導体基板１０Ａの受光面（表面）にテクスチャ構造（図３ではテクスチャ構造の記載を省略する）を形成し、裏面をミラー形状等の低欠陥構造にする。具体的には、硝酸、フッ酸、酢酸等を含む混酸にｎ型半導体基板を浸し、欠陥を除去する。次いで、受光面のみをアルカリエッチング、プラズマエッチング等の手法により、テクスチャ構造を形成する。受光面にテクスチャ構造を形成することで、光閉じ込め効果が促される。また裏面をミラー形状等にすることで、裏面表面でのキャリアの再結合を抑制することができ、太陽電池素子の高効率化が図られる。 First, as shown in FIG. 3A, a texture structure (the description of the texture structure is omitted in FIG. 3) is formed on the light receiving surface (front surface) of the n-type semiconductor substrate 10A, and the back surface is a low defect structure such as a mirror shape. To. Specifically, the n-type semiconductor substrate is immersed in a mixed acid containing nitric acid, hydrofluoric acid, acetic acid, and the like to remove defects. Next, a texture structure is formed only on the light receiving surface by a technique such as alkali etching or plasma etching. By forming a texture structure on the light receiving surface, a light confinement effect is promoted. Moreover, by making the back surface into a mirror shape or the like, carrier recombination on the back surface can be suppressed, and high efficiency of the solar cell element can be achieved.
　次に、ｎ型半導体基板１０Ａの裏面に、本発明のｎ型拡散層形成組成物及びｐ型拡散層形成組成物をそれぞれ部分的に付与し乾燥することで、図３（２）に示すようにｎ型拡散層形成組成物層１２及びｐ型拡散層形成組成物層１９をそれぞれ形成する。ｐ型拡散層形成組成物としては、Ｂ（ボロン）等の第１３族の元素を含む化合物（好ましくは、ガラス粒子の形態）と、分散媒とを含む組成物を挙げることができる。
　前記ｎ型拡散層形成組成物及びｐ型拡散層形成組成物の付与方法に特に制限はない。例えば、印刷法、スピン法、刷毛塗り、スプレー法、ドクターブレード法、ロールコーター法、及びインクジェット法がある。乾燥する方法に特に制限はない。例えば、ホットプレート、乾燥機を使用して乾燥することができる。 Next, the n-type diffusion layer forming composition and the p-type diffusion layer forming composition of the present invention are partially applied to the back surface of the n-type semiconductor substrate 10A and dried, as shown in FIG. The n-type diffusion layer forming composition layer 12 and the p-type diffusion layer forming composition layer 19 are formed respectively. Examples of the p-type diffusion layer forming composition include a composition containing a compound (preferably in the form of glass particles) containing a Group 13 element such as B (boron) and a dispersion medium.
There is no restriction | limiting in particular in the provision method of the said n type diffused layer formation composition and p type diffused layer formation composition. For example, there are a printing method, a spin method, a brush coating, a spray method, a doctor blade method, a roll coater method, and an ink jet method. There is no restriction | limiting in particular in the method of drying. For example, it can dry using a hot plate and a dryer.
　次いで、ｎ型拡散層形成組成物層１２及びｐ型拡散層形成組成物層１９が形成された半導体基板を熱処理することで、ｐ＋型拡散層１８及びｎ＋型拡散層１４が、図３（３）に示すようにそれぞれ特定の領域に形成される。熱処理の条件に特に制限はない。例えばｐ＋型拡散層の表面シート抵抗値が３０Ω／□～１４０Ω／□、ｎ＋型拡散層の表面シート抵抗値が３０Ω／□～１００Ω／□となるように熱処理することが好ましい。具体的には８００℃～１０００℃で５分～１２０分間の熱処理を行うことが好ましい。ｎ型拡散層形成組成物が特定化合物を含んで、ドナー元素の拡散能力が制御されているため、ｐ＋型拡散層とｎ＋型拡散層を同時に形成することができ、製造工程を簡略化できる。なお、熱処理時の炉内雰囲気は、空気、酸素、窒素等に適宜調節することができる。 Next, by heat-treating the semiconductor substrate on which the n-type diffusion layer forming composition layer 12 and the p-type diffusion layer forming composition layer 19 are formed, the p + -type diffusion layer 18 and the n + -type diffusion layer 14 become as shown in FIG. As shown in (3), each is formed in a specific region. There are no particular restrictions on the conditions for the heat treatment. For example, heat treatment is preferably performed so that the surface sheet resistance value of the p + -type diffusion layer is 30Ω / □ to 140Ω / □, and the surface sheet resistance value of the n + -type diffusion layer is 30Ω / □ to 100Ω / □. Specifically, it is preferable to perform a heat treatment at 800 ° C. to 1000 ° C. for 5 minutes to 120 minutes. Since the n-type diffusion layer forming composition contains a specific compound and the diffusion capacity of the donor element is controlled, the p + -type diffusion layer and the n + -type diffusion layer can be formed at the same time, thus simplifying the manufacturing process. it can. Note that the atmosphere in the furnace during the heat treatment can be appropriately adjusted to air, oxygen, nitrogen, or the like.
　熱処理後、形成されたｎ＋型拡散層の上にはｎ型拡散層形成組成物の熱処理物層１２Ａとしてリン酸ガラス層等のガラス層が形成される。またｐ＋型拡散層の上にはｐ型拡散層形成組成物の熱処理物層１９Ａとしてホウ珪酸ガラス層等のガラス層が形成されている。これらのガラス層はフッ酸処理等のエッチング処理により、図３（４）に示すように除去される。エッチング処理後に、必要に応じて超音波洗浄、シャワー洗浄、バブリング洗浄等を行うことで、フッ酸処理に由来する不要なゴミ等を除去することができる。 After the heat treatment, a glass layer such as a phosphate glass layer is formed on the formed n + -type diffusion layer as the heat-treated product layer 12A of the n-type diffusion layer forming composition. On the p + type diffusion layer, a glass layer such as a borosilicate glass layer is formed as the heat-treated product layer 19A of the p-type diffusion layer forming composition. These glass layers are removed by etching treatment such as hydrofluoric acid treatment as shown in FIG. By performing ultrasonic cleaning, shower cleaning, bubbling cleaning, or the like as necessary after the etching process, unnecessary dust or the like derived from the hydrofluoric acid process can be removed.
　次いで、図３（５）に示すように、受光面に反射防止膜１５、裏面にパッシベーション膜２０を形成する。反射防止膜１５は公知の技術を適用して形成される。例えば、反射防止膜１５が窒化ケイ素膜の場合には、ＳｉＨ４とＮＨ３の混合ガスを原料とするプラズマＣＶＤ法により形成する。このとき、水素が結晶中に拡散し、シリコン原子の結合に寄与しない軌道、即ちダングリングボンドと水素が結合し、欠陥を不活性化（水素パッシベーション）する。 Next, as shown in FIG. 3 (5), an antireflection film 15 is formed on the light receiving surface, and a passivation film 20 is formed on the back surface. The antireflection film 15 is formed by applying a known technique. For example, when the antireflection film 15 is a silicon nitride film, it is formed by a plasma CVD method using a mixed gas of SiH 4 and NH 3 as a raw material. At this time, hydrogen diffuses into the crystal, and orbits that do not contribute to the bonding of silicon atoms, that is, dangling bonds and hydrogen are combined to inactivate defects (hydrogen passivation).
　より具体的には、上記混合ガスの流量比ＮＨ３／ＳｉＨ４が０．０５～１．０、反応室の圧力が０．１Ｔｏｒｒ（１３．３Ｐａ）～２Ｔｏｒｒ（２６６．６Ｐａ）、成膜時の温度が３００℃～５５０℃、プラズマの放電のための周波数が１００ｋＨｚ以上の条件下で形成される。
　裏面のパッシベーション膜は受光面と同様に窒化ケイ素膜でもよいが、その他に、酸化ケイ素（ＳｉＯ２）膜、アモルファスシリコン膜などをＣＶＤ法等により形成してもよい。
　また反射防止膜及びパッシベーション膜は、それぞれ酸化ケイ素（ＳｉＯ２）膜、窒化ケイ素膜等からなる二層構造としていてもよい。 More specifically, the flow rate ratio NH 3 / SiH 4 of the mixed gas is 0.05 to 1.0, the pressure in the reaction chamber is 0.1 Torr (13.3 Pa) to 2 Torr (266.6 Pa), and during film formation The film is formed under the conditions of a temperature of 300 ° C. to 550 ° C. and a frequency for plasma discharge of 100 kHz or more.
The passivation film on the back surface may be a silicon nitride film as in the case of the light receiving surface, but a silicon oxide (SiO 2 ) film, an amorphous silicon film, or the like may be formed by a CVD method or the like.
The antireflection film and the passivation film may each have a two-layer structure made of a silicon oxide (SiO 2 ) film, a silicon nitride film, or the like.
　その後、半導体基板上に形成されたｎ＋型拡散層及びｐ＋型拡散層の上にそれぞれ電極を形成する。電極の形成は例えば、ファイアースルー性を有するガラス粉末を含む電極形成用金属ペースト層１７Ａをパッシベーション膜２０上に形成する。次いでこれを焼成処理することで、図３（７）に示すようにパッシベーション膜２０を貫通した裏面電極１７を形成することができる。電極形成用金属ペーストの組成は特に制限されない。アルミニウム、銀、銅等の金属と、ファイアースルー性を有するガラス粉末とを含むものを用いることができる。 Thereafter, an electrode is formed on each of the n + type diffusion layer and the p + type diffusion layer formed on the semiconductor substrate. The electrode is formed, for example, by forming an electrode forming metal paste layer 17A containing glass powder having fire-through properties on the passivation film 20. Next, by baking this, a back electrode 17 penetrating the passivation film 20 can be formed as shown in FIG. The composition of the electrode forming metal paste is not particularly limited. What contains metals, such as aluminum, silver, copper, and the glass powder which has fire through property, can be used.
　図３に示す製造工程を含む製造方法で製造される太陽電池素子では、受光面に電極が存在しないため、太陽光を有効に取り込むことができる。 In the solar cell element manufactured by the manufacturing method including the manufacturing process shown in FIG. 3, since no electrode is present on the light receiving surface, sunlight can be taken in effectively.
　以下、本発明を実施例により具体的に説明するが、本発明はこれらの実施例に限定されるものではない。尚、「％」は特に断りのない限り「質量％」を意味する。 Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples. “%” Means “mass%” unless otherwise specified.
＜実施例１＞
(ｎ型拡散層形成組成物の調製)
　エチルセルロース（ダウケミカル社製、エトセル「ＳＴＤ２００」）を３．８質量％含むテルピネオール（日本テルペン化学社製、テルピネオール－ＬＷ）溶液を調製した。この溶液９ｇと、ドナー元素を含む化合物として五酸化二リン１ｇと、を乳鉢で混合し、ペースト状とした。次いでこのペースト１０ｇに酸化マグネシウム（和光純薬工業製、体積平均粒子径０．２μｍ、略球状）を０．１ｇ加え、乳鉢で混合して、第二のｎ型拡散層形成組成物として、ｎ型拡散層形成組成物を調製した。 <Example 1>
(Preparation of n-type diffusion layer forming composition)
A solution of terpineol (manufactured by Nippon Terpene Chemical Co., Ltd., Terpineol-LW) containing 3.8% by mass of ethyl cellulose (manufactured by Dow Chemical Co., Ltd., Etcelle “STD200”) was prepared. 9 g of this solution and 1 g of diphosphorus pentoxide as a compound containing a donor element were mixed in a mortar to obtain a paste. Next, 0.1 g of magnesium oxide (manufactured by Wako Pure Chemical Industries, volume average particle size 0.2 μm, substantially spherical) is added to 10 g of this paste and mixed in a mortar to obtain n as a second n-type diffusion layer forming composition. A mold diffusion layer forming composition was prepared.
（評価用ｎ＋＋型拡散層形成組成物αの調製）
　エチルセルロース（ダウケミカル社製、エトセル「ＳＴＤ２００」）を３．８％含むテルピネオール（日本テルペン化学社製、テルピネオール－ＬＷ）溶液を調製した。この溶液９ｇと、ドナー元素を含む化合物として五酸化二リン（高純度化学研究所製）１ｇと、を乳鉢で混合し、第一のｎ型拡散層形成組成物として、ｎ＋＋型拡散層形成組成物αを調製した。 (Preparation of n ++ type diffusion layer forming composition α for evaluation)
A solution of terpineol (manufactured by Nippon Terpene Chemical Co., Ltd., Terpineol-LW) containing 3.8% of ethyl cellulose (manufactured by Dow Chemical Co., Ltd., Etcelle “STD200”) was prepared. 9 g of this solution and 1 g of diphosphorus pentoxide (manufactured by High-Purity Chemical Laboratory) as a compound containing a donor element are mixed in a mortar to form an n ++- type diffusion layer as a first n-type diffusion layer forming composition. Composition α was prepared.
（ｎ型拡散層付き半導体基板の製造）
　テクスチャ構造を有するｐ型シリコン基板（以下、単に「ｐ型シリコン基板」ともいう）表面上に、スクリーン印刷によってｎ＋＋型拡散層形成組成物αを部分的に付与し、１５０℃のホットプレート上で１分間乾燥させて、第一の組成物層を形成した。続いて前記ｎ型拡散層形成組成物の調製で得られたｎ型拡散層形成組成物を、ｐ型シリコン基板表面の第一の組成物層上を含む全面に付与し、１５０℃のホットプレート上で１分間乾燥して第二の組成物層を形成した。
　空気を５Ｌ／ｍｉｎ．で流した９５０℃のトンネル炉（横型チューブ拡散炉　ＡＣＣＵＲＯＮ　ＣＱ－１２００、国際電気製）で１０分間、熱拡散処理を行った。その後、ｐ型シリコン基板表面上に形成されたガラス層を除去するため、基板を、２．５質量％ＨＦ水溶液に５分間浸漬し、次いで流水洗浄、超音波洗浄、乾燥を行って、ｎ＋＋型拡散層及びｎ＋型拡散層がそれぞれ形成されたｐ型シリコン基板を得た。 (Manufacture of semiconductor substrate with n-type diffusion layer)
On the surface of a p-type silicon substrate having a texture structure (hereinafter, also simply referred to as “p-type silicon substrate”), an n ++ -type diffusion layer forming composition α is partially applied by screen printing on a hot plate at 150 ° C. And dried for 1 minute to form a first composition layer. Subsequently, the n-type diffusion layer forming composition obtained by the preparation of the n-type diffusion layer forming composition is applied to the entire surface including the first composition layer on the surface of the p-type silicon substrate, and a hot plate at 150 ° C. A second composition layer was formed by drying for 1 minute.
Air is 5 L / min. Thermal diffusion treatment was performed for 10 minutes in a tunnel furnace (horizontal tube diffusion furnace ACCURON CQ-1200, manufactured by Kokusai Electric) at 950 ° C., which was flowed in Thereafter, in order to remove the glass layer formed on the surface of the p-type silicon substrate, the substrate is immersed in an aqueous 2.5% by mass HF solution for 5 minutes, and then washed with running water, ultrasonically washed, and dried, and n ++ A p-type silicon substrate on which a type diffusion layer and an n + type diffusion layer were formed was obtained.
［評価］
（シート抵抗の測定）
　ｎ＋＋型拡散層形成組成物α及びｎ型拡散層形成組成物を塗布したそれぞれの領域について、ｐ型シリコン基板の表面のシート抵抗値を、三菱化学（株）製Ｌｏｒｅｓｔａ－ＥＰ　ＭＣＰ－Ｔ３６０型低抵抗率計を用いて四探針法により測定した。
　ｎ＋＋型拡散層形成組成物αを塗布した領域(ｎ＋＋型拡散層)の表面シート抵抗値は３５Ω／□であり、ｎ型拡散層形成組成物を塗布した領域(ｎ＋型拡散層)の表面シート抵抗値は５５Ω／□であった。すなわち、ドナー元素であるリンの拡散濃度が異なる２種のｎ型拡散層が選択的に形成されたｐ型シリコン基板が得られた。 [Evaluation]
(Sheet resistance measurement)
For each region where the n ++ type diffusion layer forming composition α and the n type diffusion layer forming composition were applied, the sheet resistance value of the surface of the p type silicon substrate was calculated as Loresta-EP MCP-T360 type manufactured by Mitsubishi Chemical Corporation. Measurement was performed by a four-probe method using a low resistivity meter.
The surface sheet resistance value of the region where the n ++ type diffusion layer forming composition α is applied (n ++ type diffusion layer) is 35Ω / □, and the region where the n type diffusion layer forming composition is applied (n ++ type diffusion layer) The surface sheet resistance value was 55Ω / □. That is, a p-type silicon substrate in which two types of n-type diffusion layers having different diffusion concentrations of phosphorus as a donor element were selectively formed was obtained.
（太陽電池素子の作製）
　ｎ＋型拡散層及びｎ＋＋型拡散層が形成されたｐ型シリコン基板の受光面のｎ＋＋拡散層が形成された領域の上部にＡｇ電極ペーストをスクリーン印刷にて付与して、Ａｇを含む電極形成用組成物層を形成した。また裏面の全面には、Ａｌ電極ペーストをスクリーン印刷して、Ａｌを含む電極形成用組成物層を形成した。
　次いで焼成炉を用いて第一ゾーン：４００℃，第二ゾーン：８５０℃，第三ゾーン：６５０℃にてタクトタイム１０秒で焼成処理した後、エッジをカットして太陽電池素子を得た。
　得られた太陽電池素子について、Ｉ－Ｖ特性を太陽電池評価システム（エヌエフ回路設計ブロック、Ａｓ－５１０－ＰＶ）を用いて評価したところ、変換効率は９．２％であった。 (Production of solar cell element)
The n + -type diffusion layer and the n ++ type diffusion layer is formed on the p-type silicon substrate Ag electrode paste at the top of the region n ++ diffusion layer is formed of a light-receiving surface of the imparted by screen printing, including Ag An electrode forming composition layer was formed. An Al electrode paste was screen-printed on the entire back surface to form an electrode-forming composition layer containing Al.
Next, using a firing furnace, firing was performed at a first zone: 400 ° C., a second zone: 850 ° C., and a third zone: 650 ° C. with a tact time of 10 seconds, and then the edge was cut to obtain a solar cell element.
When the obtained solar cell element was evaluated for IV characteristics using a solar cell evaluation system (NF circuit design block, As-510-PV), the conversion efficiency was 9.2%.
＜実施例２＞
（ｎ型拡散層形成組成物の調製）
　ＳｉＯ２（和光純薬工業製）、Ｐ２Ｏ５（和光純薬工業製）、ＣａＣＯ３（和光純薬工業製）を原料として用い、それぞれのモル比がＳｉＯ２：Ｐ２Ｏ５：ＣａＣＯ３＝３０：６０：１０となるように混合したものをアルミナ坩堝に入れて、室温から１４００℃まで４００℃／ｈで昇温後、１時間保持し、次いで急冷してＰ２Ｏ５－ＳｉＯ２－ＣａＯ系ガラスを得た。得られたガラスを、自動乳鉢混練装置を用いて粉砕して、ドナー元素としてＰ（リン）を含むガラス粒子を粉末状態で得た。 <Example 2>
(Preparation of n-type diffusion layer forming composition)
SiO 2 (manufactured by Wako Pure Chemical Industries, Ltd.), P 2 O 5 (manufactured by Wako Pure Chemical Industries, Ltd.), CaCO 3 (manufactured by Wako Pure Chemical Industries, Ltd.) are used as raw materials, and the respective molar ratios are SiO 2 : P 2 O 5 : CaCO. 3 = 30: 60: 10 was mixed in an alumina crucible, heated from room temperature to 1400 ° C. at 400 ° C./h, held for 1 hour, and then rapidly cooled to P 2 O 5 —SiO 2 A 2- CaO glass was obtained. The obtained glass was pulverized using an automatic mortar kneading apparatus to obtain glass particles containing P (phosphorus) as a donor element in a powder state.
　得られたガラス粒子の粉末Ｘ線回折（ＸＲＤ）パターンを、Ｎｉフィルターを用いたＣｕ－Ｋα線を用いて、Ｘ線回折装置（理学製、ＲＩＮＴ－２０００）により測定したところ、非晶質であることが確認された。
　また、得られたガラス粒子の粒子径状は略球状で、体積平均粒子径をレーザー回折式粒度分布測定装置により測定したところ、８μｍであった。ここで、体積平均粒子径は、粒子に照射したレーザー光の散乱光強度と角度の関係を検出し、Ｍｉｅ散乱理論に基づいて算出した。試料０．１ｇを分散媒であるテルピネオール１０ｇに分散したものを測定サンプルとして用いた。レーザー光の波長は７５０ｎｍであった。
　なお、ガラス粒子形状は、（株）日立ハイテクノロジーズ製ＴＭ－１０００型走査型電子顕微鏡を用いて観察して判定した。 When the powder X-ray diffraction (XRD) pattern of the obtained glass particles was measured with an X-ray diffractometer (RINT-2000, manufactured by Rigaku Corp.) using Cu—Kα ray using a Ni filter, it was amorphous. It was confirmed that there was.
Moreover, the particle diameter of the obtained glass particles was substantially spherical, and the volume average particle diameter was measured by a laser diffraction particle size distribution measuring device to be 8 μm. Here, the volume average particle diameter was calculated based on the Mie scattering theory by detecting the relationship between the scattered light intensity and the angle of the laser light applied to the particles. A sample obtained by dispersing 0.1 g of a sample in 10 g of terpineol as a dispersion medium was used as a measurement sample. The wavelength of the laser beam was 750 nm.
The glass particle shape was determined by observation using a TM-1000 scanning electron microscope manufactured by Hitachi High-Technologies Corporation.
　次に、エチルセルロースを３．８％含むテルピネオール溶液を調製した。この溶液９ｇと、ドナー元素を含む化合物として上記で得られたガラス粒子１ｇとを乳鉢で混合し、ペースト状とした。次いで、このペースト１０ｇに酸化マグネシウム（和光純薬工業製、体積平均粒子径０．２μｍ、略球状）を０．１ｇ加えて混合し、実施例２のｎ型拡散層形成組成物として、ｎ型拡散層形成組成物を調製した。 Next, a terpineol solution containing 3.8% ethyl cellulose was prepared. 9 g of this solution and 1 g of the glass particles obtained above as a compound containing a donor element were mixed in a mortar to obtain a paste. Next, 0.1 g of magnesium oxide (manufactured by Wako Pure Chemical Industries, volume average particle size 0.2 μm, substantially spherical) is added to 10 g of this paste and mixed, and the n-type diffusion layer forming composition of Example 2 is used as an n-type. A diffusion layer forming composition was prepared.
（ｎ＋＋型拡散層形成組成物βの調製）
　エチルセルロースを３．８％含むテルピネオール溶液を調製した。この溶液９ｇと、ドナー元素を含む化合物として上記で得られたガラス粉末１ｇとを乳鉢で混合し、第一のｎ型拡散層形成組成物として、ｎ＋＋型拡散層形成組成物βを調製した。 (Preparation of n ++ type diffusion layer forming composition β)
A terpineol solution containing 3.8% ethylcellulose was prepared. 9 g of this solution and 1 g of the glass powder obtained above as a compound containing a donor element were mixed in a mortar to prepare an n ++ type diffusion layer forming composition β as a first n type diffusion layer forming composition. .
　ｎ＋＋型拡散層形成組成物αの代わりにｎ＋＋型拡散層形成組成物βを用いたこと以外は、実施例１と同様にして、実施例２のｎ型拡散層形成組成物について評価を行なった。 except for using n ++ type diffusion layer forming composition β instead of n ++ type diffusion layer forming composition α, the same procedure as in Example 1, evaluated n-type diffusion layer-forming composition of Example 2 I did it.
［評価］
（シート抵抗の測定）
　ｎ＋＋型拡散層形成組成物βを付与した領域(ｎ＋＋型拡散層)の表面シート抵抗値は３０Ω／□であり、ｎ型拡散層形成組成物を付与した領域(ｎ＋型拡散層)の表面シート抵抗値は５０Ω／□であった。すなわち、ドナー元素であるリンの拡散濃度が異なる２種のｎ型拡散層が選択的に形成されたｐ型シリコン基板が得られた。 [Evaluation]
(Sheet resistance measurement)
The surface sheet resistance value of the region to which the n ++ type diffusion layer forming composition β is applied (n ++ type diffusion layer) is 30Ω / □, and the region to which the n type diffusion layer forming composition is applied (n + type diffusion layer) The surface sheet resistance value was 50Ω / □. That is, a p-type silicon substrate in which two types of n-type diffusion layers having different diffusion concentrations of phosphorus as a donor element were selectively formed was obtained.
（太陽電池素子の作製）
　さらに得られたｐ型シリコン基板を用いて、実施例１と同様にして太陽電池素子を作製して評価したところ、変換効率は９．６％であった。 (Production of solar cell element)
Further, using the obtained p-type silicon substrate, a solar cell element was produced and evaluated in the same manner as in Example 1. As a result, the conversion efficiency was 9.6%.
＜実施例３～１０、比較例１～３＞
（ｎ型拡散層形成組成物の調製）
　ｎ型拡散層形成組成物の調製に用いた材料を表１に示すように変更したこと以外は、実施例２と同様にして、実施例３～１０及び比較例１～３のｎ型拡散層形成組成物を調製した。なお、表１中の数値は配合量（ｇ）を示し、「－」は未配合であることを示す。 <Examples 3 to 10, Comparative Examples 1 to 3>
(Preparation of n-type diffusion layer forming composition)
The n-type diffusion layers of Examples 3 to 10 and Comparative Examples 1 to 3 were the same as Example 2 except that the materials used for the preparation of the n-type diffusion layer forming composition were changed as shown in Table 1. A forming composition was prepared. The numerical values in Table 1 indicate the blending amount (g), and “-” indicates that the blending is not performed.
［評価］
　実施例３～１０及び比較例１～３のｎ型拡散層形成組成物を用いた以外は実施例２と同様にして、それぞれ評価を行なった。結果を表１に示す。
　なお、表１に記載の実施例３～１０及び比較例１～３で用いた化合物は、以下の通りである。
・酸化マグネシウム（和光純薬工業社製、体積平均粒子径０．２μｍ）
・水酸化カルシウム（和光純薬工業社製、体積平均粒子径１．５μｍ）
・炭酸カルシウム（高純度化学社製、２．０μｍ）
・炭酸マグネシウム（和光純薬工業社製、体積平均粒子径２．０μｍ）
・酸化カリウム（和光純薬工業社製、体積平均粒子径３．５μｍ）
・酸化ケイ素（高純度化学研究所社製、体積平均粒子径１．０μｍ）
・ポリエチレンイミン（和光純薬工業社製、体積平均粒子径１．０μｍ）
・酸化鉄（和光純薬工業社製、体積平均粒子径１．０μｍ） [Evaluation]
Evaluations were made in the same manner as in Example 2, except that the n-type diffusion layer forming compositions of Examples 3 to 10 and Comparative Examples 1 to 3 were used. The results are shown in Table 1.
The compounds used in Examples 3 to 10 and Comparative Examples 1 to 3 shown in Table 1 are as follows.
Magnesium oxide (Wako Pure Chemical Industries, volume average particle size 0.2 μm)
・ Calcium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd., volume average particle size 1.5 μm)
・ Calcium carbonate (manufactured by High Purity Chemical Co., 2.0μm)
Magnesium carbonate (manufactured by Wako Pure Chemical Industries, Ltd., volume average particle size 2.0 μm)
・ Potassium oxide (manufactured by Wako Pure Chemical Industries, Ltd., volume average particle size 3.5 μm)
・ Silicon oxide (manufactured by High Purity Chemical Laboratory Co., Ltd., volume average particle size 1.0 μm)
・ Polyethyleneimine (manufactured by Wako Pure Chemical Industries, Ltd., volume average particle size 1.0 μm)
・ Iron oxide (manufactured by Wako Pure Chemical Industries, Ltd., volume average particle size 1.0 μm)
Figure JPOXMLDOC01-appb-T000001
  
 
Figure JPOXMLDOC01-appb-T000001
  
 
　実施例１～１０のｎ型拡散層形成組成物を用いることで、特定の領域にｎ型拡散層を形成することができた。また実施例１～１０のｎ型拡散層形成組成物と、ｎ＋＋型拡散層形成組成物α又はβを用いることで、異なる拡散濃度の拡散層を、一度の熱拡散処理で形成することができた。また、水酸化カルシウムの配合量が１ｇである実施例４のシート抵抗値は９５Ω、水酸化カルシウムの配合量が０．５ｇである実施例４のシート抵抗値は８５Ω、水酸化カルシウムの配合量が０．０１ｇである実施例４のシート抵抗値は４０Ωであった。このことから、本発明のｎ型拡散層形成組成物は、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物（特定化合物）の配合量を調整することで、容易に拡散濃度を調整できることが分かる。また実施例１～１０のｎ型拡散層形成組成物を用いて作成した太陽電池素子の変換効率はいずれも良好であった。 By using the n-type diffusion layer forming compositions of Examples 1 to 10, an n-type diffusion layer could be formed in a specific region. Further, by using the n-type diffusion layer forming compositions of Examples 1 to 10 and the n ++ type diffusion layer forming composition α or β, diffusion layers having different diffusion concentrations can be formed by a single thermal diffusion treatment. did it. Further, the sheet resistance value of Example 4 in which the compounding amount of calcium hydroxide is 1 g is 95Ω, the sheet resistance value of Example 4 in which the compounding amount of calcium hydroxide is 0.5 g is 85Ω, and the compounding amount of calcium hydroxide. The sheet resistance value of Example 4 in which is 0.01 g was 40Ω. From this, the n-type diffusion layer forming composition of the present invention adjusts the blending amount of the metal compound (specific compound) containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals. This shows that the diffusion concentration can be easily adjusted. In addition, the conversion efficiency of the solar cell elements prepared using the n-type diffusion layer forming compositions of Examples 1 to 10 was good.
　一方、特定化合物を含有しない比較例１～３のｎ型拡散層形成組成物を用いた場合、第一のｎ型拡散層形成組成物を付与した領域と、第二のｎ型拡散層形成組成物を付与した領域の表面シート抵抗値に明確な差異は認められなかった。つまり、アルカリ土類金属又はアルカリ金属を有する金属化合物を含有しないｎ型拡散層形成組成物は、拡散濃度を調整する効果を有さないことが分かる。また、比較例１～３のｎ型拡散層を用いて作成した太陽電池素子の変換効率はいずれも低かった。
比較例２においては、熱拡散処理する高温（この場合、９５０℃）においてポリエチレンイミンが分解するために、拡散濃度を調整する効果が得られなかったと考えられる。比較例３においては、基板中に拡散した鉄元素が半導体基板中でキャリア（電子、ホール）の再結合中心となり、キャリアの寿命を短くしたために変換効率が低下したと考えられる。 On the other hand, when the n-type diffusion layer forming compositions of Comparative Examples 1 to 3 that do not contain a specific compound are used, the region to which the first n-type diffusion layer forming composition is applied and the second n-type diffusion layer forming composition A clear difference was not recognized in the surface sheet resistance value of the region to which the product was applied. That is, it can be seen that the n-type diffusion layer forming composition not containing an alkaline earth metal or a metal compound having an alkali metal does not have an effect of adjusting the diffusion concentration. Further, the conversion efficiency of the solar cell elements prepared using the n-type diffusion layers of Comparative Examples 1 to 3 was low.
In Comparative Example 2, it is considered that the effect of adjusting the diffusion concentration could not be obtained because polyethyleneimine was decomposed at a high temperature (in this case, 950 ° C.) subjected to thermal diffusion treatment. In Comparative Example 3, it is considered that the iron element diffused in the substrate becomes a recombination center of carriers (electrons and holes) in the semiconductor substrate, and the conversion efficiency is lowered because the lifetime of the carriers is shortened.
　以上から、本発明のｎ型拡散層形成組成物を用いることで、特定の領域にｎ型拡散層を形成することができ、かつ、形成されるｎ型拡散層におけるドナー元素の拡散濃度を容易に調節することを可能であることが分かる。 From the above, by using the n-type diffusion layer forming composition of the present invention, an n-type diffusion layer can be formed in a specific region, and the diffusion concentration of the donor element in the formed n-type diffusion layer can be easily achieved. It can be seen that it is possible to adjust to.
　日本出願２０１２－００２６３２号の開示はその全体を本明細書に援用する。
　本明細書に記載された全ての文献、特許出願、および技術規格は、個々の文献、特許出願、および技術規格が参照により取り込まれることが具体的かつ個々に記された場合と同程度に、本明細書に参照により取り込まれる。 The disclosure of Japanese Application No. 2012-002632 is incorporated herein in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims (17)

  1. 　ドナー元素を含む化合物と、
    　前記ドナー元素を含む化合物とは異なる化合物であり、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物と、
    分散媒と、を含有するｎ型拡散層形成組成物。     A compound containing a donor element;
    A compound different from the compound containing the donor element, and a metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals;
    An n-type diffusion layer forming composition containing a dispersion medium.
  2. 　前記ドナー元素を含む化合物は、Ｐ（リン）を含有する化合物である請求項１に記載のｎ型拡散層形成組成物。 2. The n-type diffusion layer forming composition according to claim 1, wherein the compound containing a donor element is a compound containing P (phosphorus).
  3. 　前記金属化合物は、マグネシウム、カルシウム、ナトリウム、カリウム、リチウム、ルビジウム、セシウム、ベリリウム、ストロンチウム、バリウム及びラジウムからなる群より選ばれる少なくとも１種の金属元素を含有する化合物である請求項１又は請求項２に記載のｎ型拡散層形成組成物。 The metal compound is a compound containing at least one metal element selected from the group consisting of magnesium, calcium, sodium, potassium, lithium, rubidium, cesium, beryllium, strontium, barium and radium. 3. The n-type diffusion layer forming composition according to 2.
  4. 　前記金属化合物の含有率が、０．０１質量％以上５０質量％以下である請求項１～請求項３のいずれか１項に記載のｎ型拡散層形成組成物。 The composition for forming an n-type diffusion layer according to any one of claims 1 to 3, wherein a content of the metal compound is 0.01 mass% or more and 50 mass% or less.
  5. 　前記金属化合物は、常温で固体の粒子であり、前記粒子の体積平均粒子径が、０．０１μｍ以上３０μｍ以下である請求項１～請求項４のいずれか１項に記載のｎ型拡散層形成組成物。 The n-type diffusion layer formation according to any one of claims 1 to 4, wherein the metal compound is particles that are solid at normal temperature, and the volume average particle diameter of the particles is 0.01 μm or more and 30 μm or less. Composition.
  6. 　前記ドナー元素を含む化合物は、Ｐ２Ｏ３及びＰ２Ｏ５からなる群より選ばれる少なくとも１種を含有する化合物である請求項１～請求項５のいずれか１項に記載のｎ型拡散層形成組成物。 The n-type diffusion according to any one of claims 1 to 5, wherein the compound containing a donor element is a compound containing at least one selected from the group consisting of P 2 O 3 and P 2 O 5. Layer forming composition.
  7. 　前記ドナー元素を含む化合物は、ガラス粒子の形態である請求項１～請求項６のいずれか１項に記載のｎ型拡散層形成組成物。 The n-type diffusion layer forming composition according to any one of claims 1 to 6, wherein the compound containing a donor element is in the form of glass particles.
  8. 　前記ガラス粒子が、Ｐ２Ｏ３及びＰ２Ｏ５からなる群より選択される少なくとも１種のドナー元素含有物質と、ＳｉＯ２、Ｋ２Ｏ、Ｎａ２Ｏ、Ｌｉ２Ｏ、ＢａＯ、ＳｒＯ、ＣａＯ、ＭｇＯ、ＢｅＯ、ＺｎＯ、ＰｂＯ、ＣｄＯ、Ｖ２Ｏ５、ＳｎＯ、ＺｒＯ２及びＭｏＯ３からなる群より選択される少なくとも１種のガラス成分物質と、を含有する請求項７に記載のｎ型拡散層形成組成物。 The glass particles include at least one donor element-containing material selected from the group consisting of P 2 O 3 and P 2 O 5 , SiO 2 , K 2 O, Na 2 O, Li 2 O, BaO, SrO, The n according to claim 7, comprising at least one glass component material selected from the group consisting of CaO, MgO, BeO, ZnO, PbO, CdO, V 2 O 5 , SnO, ZrO 2 and MoO 3. Mold diffusion layer forming composition.
  9. 　前記ガラス粒子の含有率が、１質量％以上８０質量％以下である請求項７又は請求項８に記載のｎ型拡散層形成組成物。 The composition for forming an n-type diffusion layer according to claim 7 or 8, wherein the content of the glass particles is 1% by mass or more and 80% by mass or less.
  10. 　前記ガラス粒子中のＰ２Ｏ３及びＰ２Ｏ５の総含有率が０．０１質量％以上１０質量％以下である請求項７～請求項９のいずれか１項に記載のｎ型拡散層形成組成物。 The n-type diffusion layer according to any one of claims 7 to 9, wherein a total content of P 2 O 3 and P 2 O 5 in the glass particles is 0.01 mass% or more and 10 mass% or less. Forming composition.
  11. 　有機バインダをさらに含有する請求項１～請求項１０のいずれか１項に記載のｎ型拡散層形成組成物。 The n-type diffusion layer forming composition according to any one of claims 1 to 10, further comprising an organic binder.
  12. 　半導体基板上の全面又は一部に、請求項１～請求項１１のいずれか１項に記載のｎ型拡散層形成組成物を付与してｎ型拡散層形成組成物層を形成する工程と、
    　前記組成物層が形成された半導体基板に熱処理を施す工程と、
    を有するｎ型拡散層付き半導体基板の製造方法。     A step of forming an n-type diffusion layer forming composition layer by applying the n-type diffusion layer forming composition according to any one of claims 1 to 11 to an entire surface or a part of a semiconductor substrate;
    Applying a heat treatment to the semiconductor substrate on which the composition layer is formed;
    A method for manufacturing a semiconductor substrate with an n-type diffusion layer, comprising:
  13. 　半導体基板上の一部の領域に、ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物を付与して第一の組成物層を形成する工程を更に有し、
    　前記ｎ型拡散層形成組成物層を形成する工程は、前記半導体基板上の前記第一の組成物層が形成される面と同一の面上であり、前記第一の組成物層が形成される領域とは異なる領域に、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が前記第一のｎ型拡散層形成組成物よりも大きい前記ｎ型拡散層形成組成物を付与する工程である請求項１２に記載のｎ型拡散層付き半導体基板の製造方法。     A step of forming a first composition layer by applying a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium to a partial region on a semiconductor substrate;
    The step of forming the n-type diffusion layer forming composition layer is on the same surface as the first composition layer on the semiconductor substrate, and the first composition layer is formed. The content ratio of the metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal is larger than that of the first n-type diffusion layer forming composition The method for producing a semiconductor substrate with an n-type diffusion layer according to claim 12, which is a step of applying the composition for forming an n-type diffusion layer.
  14. 　半導体基板上の一部の領域に、ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物を付与して第一の組成物層を形成する工程と、
    　前記半導体基板上の前記第一の組成物層が形成される面と同一の面上であり、前記第一の組成物層が形成される領域とは異なる領域に、請求項１～請求項１１のいずれか１項に記載のｎ型拡散層形成組成物であり、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が前記第一のｎ型拡散層形成組成物よりも大きい第二のｎ型拡散層形成組成物を付与して第二の組成物層を形成する工程と、
    　前記第一の組成物層及び第二の組成物層が形成された前記半導体基板に熱処理を施して、前記半導体基板上の前記第二の組成物層が形成された領域にｎ＋型拡散層を、前記第一の組成物層が形成された領域に前記ｎ＋型拡散層よりも小さい表面シート抵抗値を有するｎ＋＋型拡散層をそれぞれ形成する工程と、
    　前記ｎ＋＋型拡散層上に、電極を形成する工程と、
    を有する太陽電池素子の製造方法。     Providing a first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium in a partial region on a semiconductor substrate to form a first composition layer;
    A region different from a region where the first composition layer is formed on the same surface as the surface on which the first composition layer is formed on the semiconductor substrate. The n-type diffusion layer forming composition according to any one of the above, wherein the content of the metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal is the first providing a second n-type diffusion layer forming composition larger than the n-type diffusion layer forming composition to form a second composition layer;
    The semiconductor substrate on which the first composition layer and the second composition layer are formed is heat-treated, and an n + type diffusion layer is formed on the semiconductor substrate on the region where the second composition layer is formed. Forming an n ++ type diffusion layer having a surface sheet resistance value smaller than that of the n + type diffusion layer in the region where the first composition layer is formed,
    Forming an electrode on the n ++ type diffusion layer;
    The manufacturing method of the solar cell element which has this.
  15. 　前記第一のｎ型拡散層形成組成物中におけるアルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が１０質量％以下であり、前記第二のｎ型拡散層形成組成物中におけるアルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が０．０１質量％以上５０質量％以下である請求項１４に記載の太陽電池素子の製造方法。 The content ratio of the metal compound containing at least one metal element selected from the group consisting of alkaline earth metals and alkali metals in the first n-type diffusion layer forming composition is 10% by mass or less, The content of the metal compound containing at least one metal element selected from the group consisting of an alkaline earth metal and an alkali metal in the second n-type diffusion layer forming composition is 0.01% by mass or more and 50% by mass or less. The method for manufacturing a solar cell element according to claim 14.
  16. 　半導体基板上に、請求項１～請求項１１のいずれか１項に記載のｎ型拡散層形成組成物の少なくとも１種を付与して組成物層を形成する工程と、
    　前記組成物層が形成された半導体基板に熱処理を施して、ｎ型拡散層を形成する工程と、
    　前記ｎ型拡散層上に電極を形成する工程と、
    を有する太陽電池素子の製造方法。     Forming a composition layer by applying at least one n-type diffusion layer forming composition according to any one of claims 1 to 11 on a semiconductor substrate;
    Performing a heat treatment on the semiconductor substrate on which the composition layer is formed to form an n-type diffusion layer;
    Forming an electrode on the n-type diffusion layer;
    The manufacturing method of the solar cell element which has this.
  17. 　ドナー元素を含む化合物及び分散媒を含有する第一のｎ型拡散層形成組成物と、
    　請求項１～請求項１１のいずれか１項に記載のｎ型拡散層形成組成物であり、アルカリ土類金属及びアルカリ金属からなる群より選ばれる少なくとも１種の金属元素を含有する金属化合物の含有率が前記第一のｎ型拡散層形成組成物よりも大きい第二のｎ型拡散層形成組成物と、
    を有するｎ型拡散層形成組成物セット。     A first n-type diffusion layer forming composition containing a compound containing a donor element and a dispersion medium;
    The n-type diffusion layer forming composition according to any one of claims 1 to 11, wherein the metal compound contains at least one metal element selected from the group consisting of alkaline earth metals and alkali metals. A second n-type diffusion layer forming composition having a higher content than the first n-type diffusion layer forming composition;
    An n-type diffusion layer forming composition set.
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