JP2012182275A - Solar cell and method for manufacturing solar cell - Google Patents

Solar cell and method for manufacturing solar cell Download PDF

Info

Publication number
JP2012182275A
JP2012182275A JP2011043690A JP2011043690A JP2012182275A JP 2012182275 A JP2012182275 A JP 2012182275A JP 2011043690 A JP2011043690 A JP 2011043690A JP 2011043690 A JP2011043690 A JP 2011043690A JP 2012182275 A JP2012182275 A JP 2012182275A
Authority
JP
Japan
Prior art keywords
receiving surface
light
solar cell
formed
silicon substrate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2011043690A
Other languages
Japanese (ja)
Inventor
Yuji Yokozawa
hiroyuki Akada
Takayuki Isaka
Tsutomu Yamazaki
隆行 伊坂
努 山崎
雄二 横沢
博之 赤田
Original Assignee
Sharp Corp
シャープ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sharp Corp, シャープ株式会社 filed Critical Sharp Corp
Priority to JP2011043690A priority Critical patent/JP2012182275A/en
Publication of JP2012182275A publication Critical patent/JP2012182275A/en
Application status is Pending legal-status Critical

Links

Classifications

    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and 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 peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02Details
    • H01L31/0216Coatings
    • H01L31/02161Coatings for devices characterised by at least one potential jump barrier or surface barrier
    • H01L31/02167Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells
    • H01L31/02168Coatings for devices characterised by at least one potential jump barrier or surface barrier for solar cells the coatings being antireflective or having enhancing optical properties for the solar cells
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and 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 peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02Details
    • H01L31/0236Special surface textures
    • H01L31/02366Special surface textures of the substrate or of a layer on the substrate, e.g. textured ITO/glass substrate or superstrate, textured polymer layer on glass substrate
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L31/00Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and 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 peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and 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 peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/06Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and 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 peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier
    • H01L31/068Semiconductor devices sensitive to infra-red radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and 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 peculiar to the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier 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
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy
    • Y02E10/54Material technologies
    • Y02E10/547Monocrystalline silicon PV cells

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell excellent in durability and weather resistance and having an antireflection film.SOLUTION: A solar cell 1 comprises: a light receiving surface diffusion layer 6 formed on the light receiving surface side of a silicon substrate 4; a light receiving surface passivation film 13 formed on the light receiving surface diffusion layer; and an antireflection film 12 formed on the light receiving surface passivation film and including impurities having a conductivity type same with a conductivity type of the light receiving surface diffusion layer. The antireflection film is made of titanium oxide including a titanium phosphate.

Description

  The present invention relates to a solar cell and a method for manufacturing the solar cell, and more particularly to a structure on the light receiving surface side of the solar cell.

  In recent years, a solar cell that directly converts solar energy into electric energy has been rapidly expected as a next-generation energy source particularly from the viewpoint of global environmental problems. There are various types of solar cells, such as those using compound semiconductors or organic materials, but the mainstream is currently using silicon crystals. An antireflection film for suppressing reflection of incident light is formed on a light receiving surface on the incident light side of the solar cell.

  FIG. 9 is a schematic cross-sectional configuration diagram of an example of a conventional solar cell disclosed in Patent Document 1. In FIG. 101 is a silicon wafer, 102 is a diffusion layer, 103 is a titanium oxide film, 104 is a front electrode, 105 is a back electrode, and the front electrode 104 side of the solar cell 100 is a light receiving surface. In Patent Document 1, a diffusion layer 102 is formed on the surface side to be a light receiving surface of a silicon wafer 101 by applying a heat treatment by applying a mixed solution containing at least a dopant raw material, a titanate ester and alcohol to a silicon wafer. The content that the pn junction by this and the titanium oxide film which is an antireflection film are formed on the surface which becomes the light receiving surface of the silicon wafer 101 is described. As dopant materials, oxides such as phosphorus pentoxide, boron oxide, and arsenic trioxide, or organic compounds such as phosphate esters and boron esters are described. And the content which forms on a silicon wafer by using phosphorus pentoxide as a raw material for dopants and using a titanium oxide film which is a titanium oxide containing phosphorus as an antireflection film is described.

JP 57-114291 A (published July 16, 1982)

  However, in recent years, as an antireflection film, a film having higher durability and weather resistance than the titanium oxide described in Patent Document 1 has been eagerly desired.

  This invention is made | formed in view of said problem, The objective is to provide the solar cell which has the anti-reflective film excellent in durability and a weather resistance.

  The solar cell of the present invention includes a light receiving surface diffusion layer formed on the light receiving surface side of a silicon substrate, a light receiving surface passivation film formed on the light receiving surface diffusion layer, and a light receiving surface formed on the light receiving surface passivation film. And an antireflection film containing an impurity of the same conductivity type as the conductivity type of the diffusion layer, and the antireflection film is a titanium oxide containing titanium phosphate.

  Here, in the solar cell of the present invention, the sheet resistance of the light-receiving surface diffusion layer is preferably 100Ω / □ or more and less than 250Ω / □.

  In the solar cell of the present invention, it is preferable that the impurities contained in the antireflection film contain 15 wt% to 35 wt% as phosphorous oxide.

  The method for producing a solar cell of the present invention is a method for producing a solar cell having a light-receiving surface diffusion layer on the light-receiving surface side of a silicon substrate, and a compound containing impurities contained in the light-receiving surface diffusion layer on the light-receiving surface of the silicon substrate Applying a solution containing at least titanium alkoxide and alcohol and heat-treating in a nitrogen atmosphere to form a light-receiving surface diffusion layer and an antireflection film, and forming a light-receiving surface passivation film on the light-receiving surface of the silicon substrate by heat treatment A second step of forming, and the heat treatment of the second step is performed in an oxygen atmosphere.

  Here, as for the manufacturing method of the solar cell of this invention, it is preferable that the heat processing of a 2nd process is a temperature whose processing temperature is higher than 850 degreeC.

  Moreover, the manufacturing method of the solar cell of this invention WHEREIN: A back surface passivation film may be formed in the back surface of a silicon substrate in a 2nd process.

  Moreover, the manufacturing method of the solar cell of this invention may perform a 1st process and a 2nd process by a series of heat processing.

  According to the present invention, since the antireflection film contains titanium phosphate having excellent durability and weather resistance, the durability and weather resistance of the solar cell can be improved.

It is a typical back view of an example of the solar cell of this invention. It is a typical section lineblock diagram of an example of the solar cell of the present invention. It is the typical figure of the semiconductor region seen from the back side of an example of the solar cell of the present invention. It is a schematic diagram which shows an example of the manufacturing method of the solar cell of this invention. It is a schematic diagram showing the sample which evaluates the effect of this invention. It is a preparation flowchart of the sample which evaluates the effect of this invention. It is the figure which showed the X-ray-diffraction measurement result and reference for evaluating the anti-reflective film at the time of thermally oxidizing the silicon oxide film formation with oxygen with respect to the flow of FIG. It is the figure which showed the X-ray-diffraction measurement result and reference for evaluating the anti-reflective film at the time of thermally oxidizing the silicon oxide film formation with the water vapor | steam with respect to the flow of FIG. It is a typical cross-section figure of an example of the solar cell of a prior art.

  FIG. 1 and FIG. 2 are diagrams showing a solar cell of an example of the present invention in which electrodes are formed only on the back surface that is the surface opposite to the light receiving surface. FIG. 1 is a view as seen from the back surface side of the solar cell 1. On the back surface of the solar cell 1, n-type electrodes 2 and p-type electrodes 3 are alternately formed in a strip shape.

FIG. 2 is a diagram showing a cross section taken along line AA ′ shown in FIG. 1. An uneven shape 5 having a texture structure is formed on the light receiving surface of an n-type silicon substrate 4 which is a single crystal silicon substrate. This unevenness is on the order of several μm to several tens of μm. An n + layer, which is the light-receiving surface diffusion layer 6, is formed as an FSF (Front Surface Field) layer on the entire light-receiving surface, and a light-receiving surface passivation film 13 is formed on the light-receiving surface diffusion layer 6. Further, an antireflection film 12 is formed on the light receiving surface passivation film 13. Here, the light-receiving surface passivation film 13 is a silicon oxide film, and the film thickness is preferably 5 nm or more and 200 nm or less, more preferably 5 nm or more and 60 nm or less. The antireflection film 12 is formed of a film made of titanium oxide. The film thickness is, for example, 10 nm or more and 400 nm or less. Further, the antireflection film 12 contains titanium phosphate, and the phosphorus concentration is preferably 15 wt% or more and 35 wt% or less as a phosphor oxide. The phrase “phosphorus oxide containing 15 wt% or more and 35 wt% or less of the antireflection film 12” means that the content of phosphorus oxide in the antireflection film 12 is 15 wt% or more and 35 wt% or less of the entire antireflection film 12. Means. Since the antireflection film 12 contains titanium phosphate, the antireflection film 12 is excellent in durability and weather resistance.

Further, on the back surface of the n-type silicon substrate 4, a back surface passivation film 14 composed of two layers of a second back surface passivation film 8 and a first back surface passivation film 11 is formed from the n-type silicon substrate 4 side. On the back side of the n-type silicon substrate 4, n ++ regions 9 that are n-type semiconductor regions and p + regions 10 that are p-type semiconductor regions are alternately formed adjacent to each other, and the surface of the n ++ region 9 is , N ++ is more concave than the surface other than the region 9. Here, the concave depth d shown in FIG. 2 is on the order of several tens of nm. Further, an n-type electrode 2 is formed in the n ++ region 9, and a p-type electrode 3 is formed in the p + region 10. On the outermost side of the back surface of the n-type silicon substrate 4, an electrode is not formed, that is, a p + region 71, which is a semiconductor region not in contact with the electrode, is formed. In addition, there is a difference in film thickness between the back surface passivation film 14 on the n ++ region 9 and the back surface passivation film 14 on the p ++ region 10, and the back surface passivation film 14 on the n ++ region 9 is thicker. Here, since the n ++ regions 9 and the p + regions 10 are alternately formed adjacent to each other, when the reverse bias is applied to the solar cell 1, a voltage is not partially applied, Heat generation due to a typical leakage current can be avoided. The n-type impurity concentration increases in the order of the n-type silicon substrate 4, the n + layer that is the light-receiving surface diffusion layer 6, and the n ++ region 9.

FIG. 3 shows the n ++ region 9 and the p + region 10 viewed from the back side when the n-type electrode 2 and the p-type electrode 3 are removed from the solar cell 1 and the back surface passivation film 14 is further removed. It is a figure. A p + region 71 that is a semiconductor region that is not in contact with the electrode is formed on the outer peripheral edge of the back surface of the n-type silicon substrate 4 (a semiconductor region that is formed in the outer peripheral edge and is not in contact with the electrode is Hereinafter referred to as “outer peripheral semiconductor region”). Even if a semiconductor region is formed in the edge portion of the solar cell 1 by forming the p + region 71 that is an outer peripheral semiconductor region having a conductivity type different from that of the n + + region 9 around the n + + region 9, The semiconductor region and the n ++ region 9 and the p + region 10 can be electrically separated. In addition, since there is a semiconductor region that is not in contact with the electrode at the outer peripheral edge, leakage current generated through the outer peripheral edge when the reverse bias is applied to the solar cell 1 can be suppressed. In FIG. 3, the n ++ regions 9 are all connected to form one semiconductor region, but not all are necessarily connected. Further, in FIG. 3, the p + region 10 is formed by being separated into a plurality of parts, but there may be connected portions.

  Since the outermost electrodes on each side of the solar cell have the same conductivity type, it is possible to make the formed electrode a rotationally symmetric structure. When producing a solar cell module in which a plurality of solar cells are arranged, for example, FIG. There is no problem even if the solar cell shown in FIG.

  Below, an example of the manufacturing method of the solar cell of this invention is shown.

  FIG. 4 is an example of a method for manufacturing the solar cell of the present invention shown in FIGS. 1 and 2. This will be described with reference to a schematic sectional view as shown in FIG.

  First, as shown in FIG. 4A, the back surface (hereinafter referred to as the light receiving surface of the n-type silicon substrate) opposite to the surface serving as the light receiving surface of the 100 μm thick n-type silicon substrate 4 (hereinafter referred to as “light receiving surface of the n-type silicon substrate”). A texture mask 21 such as a silicon nitride film is formed on the “back surface of the n-type silicon substrate” by a CVD method or a sputtering method. After that, as shown in FIG. 4B, a concavo-convex shape 5 having a texture structure is formed on the light receiving surface of the n-type silicon substrate 4 by etching. Etching is performed, for example, with a solution in which isopropyl alcohol is added to an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide and heated to 70 ° C. or higher and 80 ° C. or lower.

Next, the next step will be described with reference to FIG. 4C, the back side of the n-type silicon substrate 4 is on the top. As shown in FIG. 4C, after removing the texture mask 21 formed on the back surface of the n-type silicon substrate 4, a diffusion mask 22 such as a silicon oxide film is formed on the light-receiving surface of the n-type silicon substrate 4. Thereafter, a masking paste containing a solvent, a thickener and a silicon oxide precursor, for example, is applied on the back surface of the n-type silicon substrate 4 in addition to the location where the n ++ region 9 is to be formed by inkjet or screen printing. Then, a diffusion mask 23 is formed by heat treatment, and phosphorus as an n-type impurity is diffused into an exposed portion of the back surface of the n-type silicon substrate 4 by vapor phase diffusion using POCl 3 , thereby forming an n ++ region 9. The

Next, as shown in FIG. 4D, the diffusion masks 22 and 23 formed on the n-type silicon substrate 4 and the glass layer formed by diffusing phosphorus in the diffusion masks 22 and 23 are treated with hydrofluoric acid. Then, thermal oxidation with oxygen or water vapor is performed to form a silicon oxide film 24. At this time, as shown in FIG. 4D, the silicon oxide film 24 on the n ++ region 9 on the back surface of the n-type silicon substrate 4 is thickened. In this embodiment, thermal oxidation is performed with water vapor at 900 ° C., the thickness of the silicon oxide film 24 other than on the n ++ region 9 is 70 nm or more and 90 nm or less, and the thickness of the silicon oxide film 24 on the n ++ region 9 is It became 250 to 350 nm. Here, the surface concentration of phosphorus in the n ++ region 9 before thermal oxidation is 5 × 10 19 / cm 3 or more, and the processing temperature range of thermal oxidation is, for example, 800 ° C. or more and 1000 ° C. by thermal oxidation with oxygen. It is 800 degreeC or more and 950 degrees C or less by thermal oxidation with water vapor | steam.

The reason why the thicknesses of the silicon oxide films are different during thermal oxidation is as follows. The growth rate of the silicon oxide film by thermal oxidation differs depending on the type and concentration of impurities diffused in the silicon substrate. In particular, when the n-type impurity concentration is high, the growth rate is increased. For this reason, the film thickness of the silicon oxide film 24 on the n ++ region 9 having a higher n-type impurity concentration than the n-type silicon substrate 4 is thicker than that on the n-type silicon substrate 4. Silicon oxide film 24 is so formed by silicon and oxygen is linked at the time of thermal oxidation, the surface of the n ++ region 9 becomes concave than the surface of the region n ++ region 9 is not formed.

Incidentally, the silicon oxide film 24, p + for use as a diffusion mask for the n ++ region at the region forming the film thickness difference of the silicon oxide film 24 with non upper and n ++ region above 9 n ++ region 9, 60 nm or more is required.

Next, as shown in FIG. 4E, the silicon oxide film 24 on the light-receiving surface of the n-type silicon substrate 4 and the silicon oxide film 24 other than on the n ++ region 9 on the back surface are removed by etching. The back side, as indicated above, the silicon oxide film 24 is thickly formed on the n ++ region 9, further n ++ region 9 on the silicon oxide film 24 and the n ++ region 9 above except the silicon oxide film 24 Therefore, the silicon oxide film 24 is left only on the n ++ region 9 due to the difference in etching rate. For example, 900 ° C. In the thermal oxidation by 30 minutes of steam to form a silicon oxide film 24, when the hydrofluoric acid treatment to remove the silicon oxide film 24 other than the upper n ++ region 9, n ++ region 9 above The film thickness of the silicon oxide film 24 is about 120 nm. As described above, if it is 60 nm or more, it functions as a diffusion mask when forming the p + region.

Further, a diffusion mask 25 such as a silicon oxide film is formed on the light-receiving surface of the n-type silicon substrate 4, and then a polymer obtained by reacting a boron compound with an organic polymer is formed on the back surface of the n-type silicon substrate 4 with an alcohol solvent. After the solution dissolved in is applied and dried, boron, which is a p-type impurity, diffuses into the exposed portion of the back surface of the n-type silicon substrate 4 by heat treatment to form ap + region. At this time, the p + region 10 and the p + region 71 are formed.

Next, the next step will be described with reference to FIG. In FIG. 4F, the light receiving surface side of the n-type silicon substrate 4 is on the top. As shown in FIG. 4F, the silicon oxide film 24 and the diffusion mask 25 formed on the n-type silicon substrate 4 and the glass layer formed by diffusing boron into the silicon oxide film 24 and the diffusion mask 25 are fluorinated. Remove by hydroacid treatment. Thereafter, a first back surface passivation film 11 that also serves as a diffusion mask such as a silicon oxide film having a thickness of 50 nm to 100 nm is formed on the back surface of the n-type silicon substrate 4 by a CVD method, or SOG (spin on glass) is applied. It is formed by firing. Thereafter, in order to form the n + layer as the light-receiving surface diffusion layer 6 and the antireflection film 12 on the light-receiving surface of the n-type silicon substrate 4, the light-receiving surface of the n-type silicon substrate 4 includes at least a phosphorus compound, titanium alkoxide, and alcohol. The mixed liquid 27 is applied and dried. Here, phosphorus pentoxide is used as the phosphorus compound of the mixed liquid 27, tetraisopropyl titanate is used as the titanium alkoxide, and isopropyl alcohol is used as the alcohol.

Next, as shown in FIG. 4G, phosphorus, which is an n-type impurity, is diffused by heat treatment, and the n + layer, which is the light-receiving surface diffusion layer 6, and the antireflection film 12 are formed on the entire light-receiving surface side. This heat treatment is performed in a nitrogen atmosphere, and the treatment temperature is, for example, 850 ° C. or higher and 1000 ° C. or lower.

In order to form a second back surface passivation film 8 made of a silicon oxide film on the back surface of the n-type silicon substrate 4, thermal oxidation with oxygen is performed. At this time, while the silicon oxide film as the second back surface passivation film 8 is formed on the back surface of the n-type silicon substrate 4, the entire light-receiving surface of the n-type silicon substrate 4 is oxidized as shown in FIG. A silicon film is formed. The silicon oxide film formed on the entire light receiving surface is formed between the light receiving surface diffusion layer 6 and the antireflection film 12 and becomes the light receiving surface passivation film 13. The reason why the light-receiving surface passivation film 13 is formed between the light-receiving surface diffusion layer 6 and the antireflection film 12 is that the film thickness of the antireflection film 12 in the concave portion of the concavo-convex shape 5 on the light receiving surface increases and the antireflection film It is considered that a crack is generated in 12 and oxygen enters from the portion where the crack is generated and a silicon oxide film which is the light-receiving surface passivation film 13 grows. Further, it is considered that oxygen is permeated and a silicon oxide film, which is a light-receiving surface passivation film, grows because the film thickness of the antireflection film 12 is thin at the convex portion of the uneven shape 5 on the light-receiving surface. Furthermore, the reason why the second back surface passivation film 8 is formed between the back surface of the n-type silicon substrate 4 and the first back surface passivation film 11 is that the first back surface passivation film 11 on the back surface of the n-type silicon substrate 4 is CVD. Since it is a film formed by a method or the like, it is considered that oxygen permeates into the first back surface passivation film 11, thereby growing a silicon oxide film as the second back surface passivation film 8. Note that the thickness of the light-receiving surface passivation film 13 is, for example, 100 nm or more and 200 nm or less, and the thickness of the second back surface passivation film 8 is, for example, 30 nm or more and 100 nm or less on the n ++ region 9 and on the p + region. Is 10 nm or more and 40 nm or less.

The second back surface passivation film 8 and the light receiving surface passivation film 13 can also be formed by performing thermal oxidation with oxygen by switching the gas following the heat treatment for forming the light receiving surface diffusion layer 6 and the antireflection film 12. It is. That is, the number of steps can be reduced by forming the heat treatment for forming the n + layer, which is the light-receiving surface diffusion layer 6 and the antireflection film 12, and the heat treatment for forming the light-receiving surface passivation film 13 by a series of heat treatments. it can.

  The recombination current on the light-receiving surface side of the solar cell 1 can be reduced by setting the silicon oxide film forming temperature as the light-receiving surface passivation film 13 to a temperature higher than 850 ° C., more preferably 900 ° C. or higher. Battery characteristics can be improved. In addition, if the sheet resistance value in the light-receiving surface diffusion layer formed in the above process is 100Ω / □ or more and less than 250Ω / □, the recombination current on the light-receiving surface side of the solar cell 1 can be reduced, It tends to improve the solar cell characteristics. The concentration of phosphorous oxide contained in the antireflection film of the solar cell in the range of the sheet resistance value was 15 wt% or more. Note that when the phosphorous oxide concentration exceeds 35 wt%, the antireflection film may turn white.

Next, as shown in FIG. 4 (h), in order to form an electrode on the n ++ region 9, p + region 10 formed on the rear surface side of the n-type silicon substrate 4, is formed on the back surface of the n-type silicon substrate Then, the back surface passivation film 14 is patterned. The patterning is performed by applying an etching paste by a screen printing method or the like and performing a heat treatment. Thereafter, the etching paste subjected to the patterning process is ultrasonically cleaned and removed by acid treatment. Here, the etching paste includes, for example, at least one selected from the group consisting of phosphoric acid, hydrogen fluoride, ammonium fluoride, and ammonium hydrogen fluoride as an etching component, and includes water, an organic solvent, and a thickener. Is included.

Next, as shown in FIG. 4I, a silver paste is applied to a predetermined position on the back surface of the n-type silicon substrate 4 by a screen printing method and dried. Then, by baking, the n-type electrode 2 was formed in the n ++ region 9, and the p-type electrode 3 was formed in the p ++ region 10, so that the solar cell 1 was produced.

  Here, a sample was prepared in order to evaluate the antireflection film, and X-ray diffraction (XRD) measurement of the antireflection film was performed.

FIG. 5 is a schematic diagram showing the manufactured sample 81. Reference numeral 82 denotes an n-type silicon substrate, 83 denotes an n + layer corresponding to the light-receiving surface diffusion layer, 84 denotes a silicon oxide film which is a passivation film, and 85 denotes a film corresponding to the antireflection film.

FIG. 6 is a manufacturing flowchart showing a method for manufacturing the sample 81 of FIG. In the sample 81 shown in FIG. 5, first, the surface of the n-type silicon substrate 82 is flattened by etching or the like (S1. “S” represents a step, and so on). A liquid mixture containing at least a phosphorus compound, titanium alkoxide and alcohol is applied to the flat surface of the n-type silicon substrate 82 and dried. Here, phosphorus pentoxide is used as the phosphorus compound of the mixed solution, tetraisopropyl titanate is used as the titanium alkoxide, and isopropyl alcohol is used as the alcohol (S2). By heat treatment, phosphorus, which is an n-type impurity, is diffused to form an n + layer 83 and a film 85 made of titanium oxide containing phosphorus. This heat treatment was performed at 920 ° C. in a nitrogen atmosphere (S3). Thermal oxidation is performed to form a silicon oxide film 84. This heat treatment was performed at 950 ° C. (S4). Here, the steps from S1 to S3 are the same, and the thermal oxidation in S4 was performed in an oxygen atmosphere as Example 1, and the one performed in a water vapor atmosphere as a comparative example.

FIG. 7 shows the XRD measurement results and reference of Example 1. (A) is an XRD measurement result of Example 1, and (b) is an XRD pattern (JCPDS (Joint Committee for Powder Standards) -ICDD (International Center for Ditar) of titanium phosphate (TiP 2 O 7 ). ) -PDF (Powder Diffraction Files)), and (c) is an XRD pattern (JCPDS-ICDD-PDF) of anatase-type titanium oxide (TiO 2 ).

FIG. 8 shows the XRD measurement results and reference of the comparative example. (A) is an XRD measurement result of a comparative example, and (b) is an XRD pattern (JCPDS-ICDD-PDF) of anatase type titanium oxide (TiO 2 ).

  As shown in FIG. 7, when the thermal oxidation of S4 is performed in an oxygen atmosphere, the film corresponding to the antireflection film is titanium phosphate and titanium phosphate in the vicinity of 47 to 48 degrees indicated by an arrow in FIG. Judging from the fact that peaks peculiar to each of titanium oxide and titanium oxide were observed side by side, a result containing a small amount of titanium oxide was obtained. Further, FIG. 8 shows that when the thermal oxidation of S4 is performed in a water vapor atmosphere, the film corresponding to the antireflection film is titanium oxide.

Therefore, the n + layer as the light-receiving surface diffusion layer and the heat treatment at the time of manufacturing the antireflection film are performed in a nitrogen atmosphere at the time of manufacturing the solar cell, and then the silicon oxide film as the light-receiving surface passivation film is formed by thermal oxidation with oxygen. By doing so, the antireflection film can be made into a film containing titanium phosphate, and by including titanium phosphate, the antireflection film becomes a film having excellent durability and weather resistance, so that the durability of the solar cell , Weather resistance can be improved.

Although an n-type silicon substrate has been described above, a p-type silicon substrate can also be used. At that time, if a light-receiving surface diffusion layer is present, it becomes a p + layer using p-type impurities, the antireflection film becomes a film containing p-type impurities, and the other structure is the structure described above for the n-type silicon substrate. It is the same.

Further, when using a p-type silicon substrate, in order to obtain a higher short-circuit current, the total area of the n ++ region where the electrode is formed is different from the p-type that is the conductivity type of the silicon substrate, It is larger than the total area of the p + region where the electrode is formed. In this case, adjacent p + regions may be separated in a direction perpendicular to the length direction. At that time, between the p + region n ++ region is formed. Further, if the n ++ region is separated in a direction perpendicular to the length direction, p + region is formed between the n ++ region.

  Furthermore, the concept of the solar cell of the present invention includes not only a solar cell in which both the p-type electrode and the n-type electrode are formed only on the back surface of the semiconductor substrate, but also the light-receiving surface of the semiconductor substrate. A solar cell in which the electrodes are formed on the surface to be formed and the surface to be the back surface, and MWT (Metal Wrap Through) type (a solar cell having a configuration in which a part of the electrode is disposed in a through hole provided in the semiconductor substrate) The solar cell of the structure of these is included.

DESCRIPTION OF SYMBOLS 1 Solar cell, 2 n-type electrode, 3 p-type electrode, 4 n-type silicon substrate, 5 uneven | corrugated shape, 6 light-receiving surface diffused layer, 8 2nd back surface passivation film, 9 n ++ area | region, 10p + area | region, 11 First back surface passivation film, 12 Antireflection film, 13 Light-receiving surface passivation film, 14 Back surface passivation film, 21 Texture mask, 22 Diffusion mask, 23 Diffusion mask, 24 Silicon oxide film, 25 Diffusion mask, 27 Mixed solution, 71 p + Region, 81 samples, 82 n-type silicon substrate, 83 n + layer, 84 silicon oxide film, 85 film made of titanium oxide, 100 solar cell, 101 silicon wafer, 102 diffusion layer, 103 titanium oxide film, 104 surface electrode, 105 Back electrode.

Claims (7)

  1. A light-receiving surface diffusion layer formed on the light-receiving surface side of the silicon substrate;
    A light-receiving surface passivation film formed on the light-receiving surface diffusion layer;
    An antireflection film formed on the light-receiving surface passivation film and containing an impurity of the same conductivity type as that of the light-receiving surface diffusion layer;
    The antireflection film is a solar cell that is a titanium oxide containing titanium phosphate.
  2.   The solar cell according to claim 1, wherein a sheet resistance of the light-receiving surface diffusion layer is 100Ω / □ or more and less than 250Ω / □.
  3.   3. The solar cell according to claim 1, wherein the impurities contained in the antireflection film contain 15 wt% to 35 wt% as phosphorous oxide.
  4. A method for producing a solar cell having a light-receiving surface diffusion layer on the light-receiving surface side of a silicon substrate,
    The light-receiving surface diffusion layer and the antireflection film are applied to the light-receiving surface of the silicon substrate by applying a solution containing at least the impurity-containing compound, titanium alkoxide and alcohol contained in the light-receiving surface diffusion layer and heat-treating in a nitrogen atmosphere. A first step of forming;
    A second step of forming a light-receiving surface passivation film by heat treatment on the light-receiving surface of the silicon substrate,
    The heat treatment in the second step is a method for manufacturing a solar cell performed in an oxygen atmosphere.
  5.   The method for manufacturing a solar cell according to claim 4, wherein the heat treatment in the second step has a treatment temperature higher than 850 ° C. 6.
  6.   The method for manufacturing a solar cell according to claim 4 or 5, wherein a back surface passivation film is formed on the back surface of the silicon substrate in the second step.
  7.   The method for manufacturing a solar cell according to claim 4, wherein the first step and the second step are performed by a series of heat treatments.
JP2011043690A 2011-03-01 2011-03-01 Solar cell and method for manufacturing solar cell Pending JP2012182275A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2011043690A JP2012182275A (en) 2011-03-01 2011-03-01 Solar cell and method for manufacturing solar cell

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2011043690A JP2012182275A (en) 2011-03-01 2011-03-01 Solar cell and method for manufacturing solar cell
PCT/JP2012/053925 WO2012117877A1 (en) 2011-03-01 2012-02-20 Solar cell, and method for producing solar cell

Publications (1)

Publication Number Publication Date
JP2012182275A true JP2012182275A (en) 2012-09-20

Family

ID=46757816

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2011043690A Pending JP2012182275A (en) 2011-03-01 2011-03-01 Solar cell and method for manufacturing solar cell

Country Status (2)

Country Link
JP (1) JP2012182275A (en)
WO (1) WO2012117877A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2701271A2 (en) 2012-08-21 2014-02-26 Makita Corporation Charger
JP2015165531A (en) * 2014-03-03 2015-09-17 三菱電機株式会社 Solar cell and manufacturing method of solar cell

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57114291A (en) * 1981-01-07 1982-07-16 Sharp Corp Manufacture of reflection preventive film
JPH0885874A (en) * 1994-07-21 1996-04-02 Sharp Corp Formation of phosphorus-containing titanium oxide film, production of solar cell and device therefor
JP2004193350A (en) * 2002-12-11 2004-07-08 Sharp Corp Solar battery cell and its manufacturing method
JP2008532311A (en) * 2005-03-03 2008-08-14 サンパワー コーポレイション Prevention of harmful polarization in solar cells

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57114291A (en) * 1981-01-07 1982-07-16 Sharp Corp Manufacture of reflection preventive film
JPH0885874A (en) * 1994-07-21 1996-04-02 Sharp Corp Formation of phosphorus-containing titanium oxide film, production of solar cell and device therefor
JP2004193350A (en) * 2002-12-11 2004-07-08 Sharp Corp Solar battery cell and its manufacturing method
JP2008532311A (en) * 2005-03-03 2008-08-14 サンパワー コーポレイション Prevention of harmful polarization in solar cells

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2701271A2 (en) 2012-08-21 2014-02-26 Makita Corporation Charger
JP2015165531A (en) * 2014-03-03 2015-09-17 三菱電機株式会社 Solar cell and manufacturing method of solar cell

Also Published As

Publication number Publication date
WO2012117877A1 (en) 2012-09-07

Similar Documents

Publication Publication Date Title
JP5390102B2 (en) Semiconductor device having heterojunction and interfinger structure
JP4481869B2 (en) Solar cell manufacturing method, solar cell, and semiconductor device manufacturing method
JP5302414B2 (en) Solar cell and manufacturing method thereof
JPWO2005109524A1 (en) Solar cell and manufacturing method thereof
CN102017188B (en) Solar cell having crystalline silicon
JP5844797B2 (en) Manufacturing method of solar cell
US20100032012A1 (en) Solar cell and method of manufacturing the same
JP2004193350A (en) Solar battery cell and its manufacturing method
JP6046661B2 (en) Solar cell, manufacturing method thereof, and method for forming impurity parts
US20100275995A1 (en) Bifacial solar cells with back surface reflector
JP6321861B2 (en) Solar cell having an emitter region containing a wide bandgap semiconductor material
JP5025184B2 (en) Solar cell element, solar cell module using the same, and manufacturing method thereof
JP2010521824A (en) Solar cell
WO2009157079A1 (en) Solar battery cell and process for producing the same
JP3722326B2 (en) Manufacturing method of solar cell
EP2908340A1 (en) Solar cell and manufacturing method thereof
JP2006120945A (en) Solar cell and solar cell module
EP2070128A2 (en) Method of manufacturing crystalline silicon solar cells with improved surface passivation
EP2171762A2 (en) Method for producing a silicon solar cell with a back-etched emitter as well as a corresponding solar cell
US20100190286A1 (en) Method for manufacturing solar cell
CN101164173A (en) Solar cell manufacturing method and solar cell
JP4767110B2 (en) Solar cell and method for manufacturing solar cell
JP2011511453A (en) Solar cell and manufacturing method thereof
TW201003934A (en) Method for manufacturing solar cell
US20120222734A1 (en) Solar battery cell and method of manufacturing the same

Legal Events

Date Code Title Description
RD01 Notification of change of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7421

Effective date: 20130131

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20131001

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20141007

RD04 Notification of resignation of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7424

Effective date: 20150129

A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20150224