WO2022145283A1 - Solar cell and solar cell manufacturing method - Google Patents

Solar cell and solar cell manufacturing method Download PDF

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Publication number
WO2022145283A1
WO2022145283A1 PCT/JP2021/047232 JP2021047232W WO2022145283A1 WO 2022145283 A1 WO2022145283 A1 WO 2022145283A1 JP 2021047232 W JP2021047232 W JP 2021047232W WO 2022145283 A1 WO2022145283 A1 WO 2022145283A1
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Prior art keywords
solar cell
semiconductor substrate
semiconductor layer
electrode
translucent
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PCT/JP2021/047232
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French (fr)
Japanese (ja)
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紳平 岡本
崇 口山
淳一 中村
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株式会社カネカ
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Priority to JP2022573009A priority Critical patent/JPWO2022145283A1/ja
Publication of WO2022145283A1 publication Critical patent/WO2022145283A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0224—Electrodes
    • 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
    • H01L31/0248—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 characterised by their semiconductor bodies
    • H01L31/0352—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 characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
    • 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 at least one potential-jump barrier or surface barrier
    • H01L31/072—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 at least one potential-jump barrier or surface barrier the potential barriers being only of the PN heterojunction type
    • H01L31/0745—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 at least one potential-jump barrier or surface barrier the potential barriers being only of the PN heterojunction type comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells
    • H01L31/0747—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 at least one potential-jump barrier or surface barrier the potential barriers being only of the PN heterojunction type comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells comprising a heterojunction of crystalline and amorphous materials, e.g. heterojunction with intrinsic thin layer or HIT® solar cells; 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
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof

Definitions

  • the present invention relates to a solar cell and a method for manufacturing a solar cell.
  • Patent Document 1 proposes etching using an electrolytic solution containing fluoride as a method for forming an opening in a semiconductor substrate at a relatively low cost.
  • the solar cell according to one aspect of the present invention is a semiconductor substrate formed in a plate shape and having a plurality of translucent openings penetrating in the thickness direction, and a first semiconductor laminated on one main surface side of the semiconductor substrate.
  • the inner peripheral surface of the translucent opening is located on the side of the first peripheral surface portion located on the side of the first semiconductor layer and on the side of the second semiconductor layer, and the surface texture is different from that of the first peripheral surface portion. It has a second peripheral surface portion.
  • the semiconductor substrate may be covered with the first semiconductor layer on the first peripheral surface portion, and the semiconductor substrate may be exposed on the second peripheral surface portion.
  • the method for manufacturing a solar cell according to one aspect of the present invention includes a step of forming an annular groove by irradiating a semiconductor substrate with laser light, and etching or cutting of the bottom of the annular groove to form the annular groove of the semiconductor substrate.
  • a step of forming an opening in the semiconductor substrate by separating the inner region is provided.
  • the above-mentioned solar cell manufacturing method may further include a step of forming a film on the semiconductor substrate between the step of forming the annular groove and the step of forming the opening.
  • a solar cell has a semiconductor substrate and a photoelectric converter having a semiconductor layer laminated on the semiconductor substrate and having a plurality of translucent openings penetrating the front and back surfaces, and the photoelectric converter.
  • the front surface electrode comprises a front surface electrode laminated on the front surface of the photoelectric converter and a back surface electrode laminated on the back surface of the photoelectric conversion body, and the front surface electrode has a plurality of surrounding portions individually surrounding the plurality of translucent openings.
  • the surrounding portion may have a polygonal shape.
  • the length of each side of the surrounding portion may be constant.
  • the minimum value of the distance between each side of the surrounding portion and the translucent opening may be 50% or more of the maximum value.
  • the distance between each side of the surrounding portion and the translucent opening may be 20% or more and 150% or less of the diameter of the translucent opening.
  • the surface electrodes are composed of a plurality of electrode wires arranged in parallel and at equal intervals, and may have three sets of electrode wire groups having different angles so as to intersect each other.
  • the surrounding portions may have a hexagonal shape that touches each other at the vertices, and may define a triangular space that does not include the translucent opening between them.
  • the area inside the plurality of surrounding parts may be twice or more and five times or less the area outside the plurality of surrounding parts.
  • the back surface electrode may have a plurality of surrounding portions individually surrounding the plurality of translucent openings.
  • FIG. 3 is a partial cross-sectional view taken along the line XX of the solar cell of FIG. It is a flowchart which shows the procedure of the solar cell manufacturing method which concerns on one Embodiment of this invention.
  • FIG. 3 is a partial cross-sectional view illustrating one step of the solar cell manufacturing method of FIG. It is a partial sectional view explaining the next process of FIG. 4 of the solar cell manufacturing method of FIG. It is a partial sectional view explaining the next process of FIG. 5 of the solar cell manufacturing method of FIG. It is a partial sectional view explaining the next process of FIG. 6 of the solar cell manufacturing method of FIG.
  • FIG. 11 is a schematic cross-sectional view taken along the line YY of the solar cell of FIG. It is a schematic plan view of the solar cell which concerns on 3rd Embodiment of this invention. It is a schematic plan view of the solar cell which concerns on 4th Embodiment of this invention. It is a schematic plan view of the solar cell which concerns on 5th Embodiment of this invention.
  • FIG. 1 is a partial plan view of the solar cell 1 according to the first embodiment of the present invention.
  • FIG. 2 is a sectional view of a solar cell.
  • the solar cell 1 has a semiconductor substrate 10 formed in a plate shape, a first semiconductor layer 20 laminated on one main surface side (light receiving surface side) of the semiconductor substrate 10, and the other main surface of the semiconductor substrate 10.
  • the second semiconductor layer 30 laminated on the side, the first passion layer 40 interposed between the semiconductor substrate 10 and the first semiconductor layer 20, and the second passion intervening between the semiconductor substrate 10 and the second semiconductor layer 30.
  • the layer 50 includes a first electrode 60 laminated on the first semiconductor layer 20, and a second electrode 70 laminated on the second semiconductor layer 30.
  • the semiconductor substrate 10 functions as a photoelectric conversion substrate that absorbs incident light and generates optical carriers (electrons and holes).
  • the semiconductor substrate 10 may have a pyramid-shaped fine uneven structure called a texture structure in order to improve the incident rate of light on the light receiving surface.
  • the semiconductor substrate 10 can be formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. Further, the semiconductor substrate 10 may be formed of another semiconductor material such as gallium arsenide (GaAs).
  • the semiconductor substrate 10 can be, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. Examples of the n-type dopant include phosphorus (P).
  • the semiconductor substrate 10 has a plurality of translucent openings 11 penetrating in the thickness direction.
  • the translucent opening 11 makes it possible to transmit light to the back surface side (opposite the light receiving surface) of the solar cell 1 and collect light.
  • the shape of the translucent opening 11 in a plan view is typically circular, but may be any shape such as an elliptical shape and a polygonal shape.
  • the translucent opening 11 is preferably formed so as to be dispersed over substantially the entire semiconductor substrate 10 in order to collect light evenly, but in order to secure the strength of the semiconductor substrate 10, for example, the peripheral portion of the semiconductor substrate 10. It may not be provided in a band-shaped region or the like that crosses the semiconductor substrate 10. It is preferable that the translucent apertures 11 are regularly arranged so as to collect light more evenly and improve the aesthetic appearance.
  • the area ratio of the translucent opening 11 in the semiconductor substrate 10, that is, the opening ratio of the semiconductor substrate 10 can be, for example, 3% or more and 50% or less, preferably 5% or more and 30% or less. As a result, sufficient light can pass through the solar cell 1 and a relatively large amount of electric power can be obtained.
  • the average diameter (diameter equivalent to a circle) of the translucent opening 11 can be, for example, 1 mm or more and 10 mm or less, preferably 2 mm or more and 8 mm or less. As a result, sufficient daylighting becomes possible while increasing the photoelectric conversion efficiency of the solar cell 1.
  • the inner peripheral surface of the translucent opening 11 is located on the side of the first peripheral surface portion 12 located on the side of the first semiconductor layer 20 and on the side of the second semiconductor layer 30, and has a second surface texture different from that of the first peripheral surface portion 12. It has a peripheral surface portion 13.
  • the "surface texture” includes a fine uneven shape, a layered structure on the surface, a metamorphic state such as oxidation of the material of the semiconductor substrate 10, and the like.
  • the first peripheral surface portion 12 of the translucent opening 11 is, for example, a laser-machined surface, and may have an oxide or the like on the inner peripheral surface of the semiconductor substrate 10. Further, in the first peripheral surface portion 12, the semiconductor substrate 10 is covered with the first passivation layer 40 and the first semiconductor layer 20. On the other hand, the semiconductor substrate 10 is exposed on the second peripheral surface portion 13.
  • the solar cell 1 since the semiconductor substrate 10 is covered with the first passivation layer 40 and the first semiconductor layer 20 in the first peripheral surface portion 12, the solar cell 1 by suppressing the recombination of carriers generated inside the semiconductor substrate 10. Improves photoelectric conversion efficiency. Further, since the translucent opening 11 has the second peripheral surface portion 13 that exposes the semiconductor substrate 10, the first semiconductor layer 20 and the second semiconductor layer 30 can be reliably insulated. That is, the inner peripheral surface of the translucent opening 11 has a first peripheral surface portion 12 that suppresses carrier recombination and a second peripheral surface portion 13 that prevents a short circuit, so that the solar cell 1 has high photoelectric conversion efficiency. Has.
  • the lower limit of the area ratio of the first peripheral surface portion 12 on the inner peripheral surface of the translucent opening 11 is preferably 50%, more preferably 60%.
  • the upper limit of the area ratio of the first peripheral surface portion 12 on the inner peripheral surface of the translucent opening 11 95% is preferable, and 90% is more preferable.
  • the first semiconductor layer 20 and the second semiconductor layer 30 collect charges of different polarities by attracting carriers having different polarities from the inside of the semiconductor substrate 10.
  • the first semiconductor layer 20 may be formed of a p-type semiconductor
  • the second semiconductor layer 30 may be formed of an n-type semiconductor.
  • the first semiconductor layer 20 and the second semiconductor layer 30 can be formed of, for example, an amorphous silicon material containing a dopant that imparts a desired conductive type.
  • a dopant that imparts a desired conductive type.
  • Examples of the p-type dopant include boron (B), and examples of the n-type dopant include phosphorus (P) described above.
  • the first semiconductor layer 20 extends to the inner peripheral surface of the translucent opening 11 and covers the inner peripheral surface of the semiconductor substrate 10 at the first peripheral surface portion 12.
  • the first passivation layer 40 and the second passivation layer 50 improve the photoelectric conversion efficiency of the solar cell 1 by suppressing the recombination of the carriers generated inside the semiconductor substrate 10 on the surface of the semiconductor substrate 10.
  • the first passivation layer 40 and the second passivation layer 50 can be an intrinsic semiconductor layer formed of amorphous silicon.
  • the first passivation layer 40 extends to the inner peripheral surface of the translucent opening 11 and covers the inner peripheral surface of the semiconductor substrate 10 at the first peripheral surface portion 12.
  • the first electrode 60 and the second electrode 70 take out the carriers attracted by the first semiconductor layer 20 and the second semiconductor layer 30 as electric charges.
  • the first electrode 60 and the second electrode 70 are preferably made of a material having conductivity and mainly made of a metal having a small electric resistance.
  • the first electrode 60 and the second electrode 70 can be formed of metal, silver paste, or the like.
  • the first electrode 60 on the light receiving surface side is preferably formed in a plurality of linear shapes in order to reduce the area so that light can be incident on the semiconductor substrate 10. Further, the first electrode 60 may be formed in a mesh shape in order to reduce the region where the moving distance of the carrier becomes large.
  • the second electrode 70 may be formed in the same shape as the first electrode 60, but in order to reduce the moving distance of the carrier to the second electrode 70 and the electric resistance in the second electrode 70, the second electrode 70 may be formed. It may be provided on substantially the entire surface of a region other than the translucent opening 11.
  • the solar cell 1 is high because the inner peripheral surface of the translucent opening 11 has a first peripheral surface portion 12 that suppresses carrier recombination and a second peripheral surface portion 13 that prevents a short circuit. Photoelectric conversion efficiency can be achieved.
  • the solar cell 1 can be manufactured by one embodiment of the solar cell manufacturing method according to the present invention.
  • the solar cell cell manufacturing method of the present embodiment includes an annular groove forming step (step S1), a passage layer forming step (step S2), and a first semiconductor layer forming step (step S3).
  • a second semiconductor layer film forming step (step S4), a first electrode forming step (step S5), a second electrode forming step (step S6), and a translucent opening forming step (step S7) are provided. ..
  • the planar shape of the annular groove G is an endless loop shape corresponding to the outer shape of the translucent opening 11, and is not limited to a circular shape.
  • the depth of the annular groove G is determined corresponding to the height of the first peripheral surface portion 12.
  • a film is formed on the inner surface of the annular groove G in the passivation layer film forming step and the first semiconductor layer film forming step. Therefore, the width of the annular groove G is set so that the film-forming gas can be supplied to the inner part of the annular groove G.
  • the materials forming the first passivation layer 40 and the second passivation layer 50 are laminated on both sides of the semiconductor substrate 10 and the inner surface of the annular groove G.
  • the first passivation layer 40 and the second passivation layer 50 can be formed by, for example, a film forming technique such as CVD or PVD. This passivation layer film forming step may be performed in two steps for each side of the semiconductor substrate 10.
  • the first semiconductor layer 20 is formed on the surface of the first passivation layer 40 on the main surface of the semiconductor substrate 10 on the light receiving side and the inner surface of the annular groove G. Laminate the materials to be formed.
  • the first semiconductor layer 20 can also be formed by, for example, a film forming technique such as CVD or PVD, like the first passivation layer 40 and the second passivation layer 50.
  • a material for forming the second semiconductor layer 30 on the surface of the second passivation layer 50 on the main surface opposite to the light receiving surface of the semiconductor substrate 10. are laminated.
  • the second semiconductor layer 30 can also be formed by, for example, a film forming technique such as CVD or PVD.
  • the first electrode 60 is formed by, for example, printing and firing of a conductive paste, laminating of a metal layer, and etching of a metal layer using a resist pattern. do.
  • the second electrode 70 is formed by, for example, printing and firing of a conductive paste, laminating of a metal layer, and etching of a metal layer using a resist pattern. do.
  • the firing or etching in the second electrode forming step may be performed at the same time as the firing or etching in the first electrode forming step.
  • the translucent opening 11 is formed by separating the inner region of the annular groove G of the semiconductor substrate 10 by etching or cutting the bottom of the annular groove G. As a result, the solar cell 1 shown in FIG. 1 is obtained.
  • the inner region of the annular groove G can be separated by pressing a jig having a protrusion on the portion corresponding to the inside of the annular groove G.
  • the translucent opening 11 has different surface textures of the first peripheral surface portion 12 and the second peripheral surface portion. It will have 13 and.
  • the first peripheral surface portion 12 that suppresses carrier recombination and the second circumference that prevents a short circuit are prevented. Since the surface portion 13 can be reliably formed, the solar cell 1 having high photoelectric conversion efficiency can be manufactured relatively easily.
  • FIG. 11 is a schematic plan view of the solar cell 101 according to the first embodiment of the present invention.
  • FIG. 12 is a schematic cross-sectional view of the solar cell 101.
  • the solar cell 101 includes a plate-shaped photoelectric converter 110, a front electrode 120 laminated on the surface of the photoelectric converter 110, and a back surface electrode 130 laminated on the back surface of the photoelectric converter 110.
  • the surface on the side where light is incident is referred to as the front surface, and the opposite side thereof is referred to as the back surface.
  • the photoelectric converter 110 has a semiconductor substrate 111, a first semiconductor layer 112 laminated on the surface of the semiconductor substrate 111, and a second semiconductor layer 113 laminated on the back surface of the semiconductor substrate 111.
  • the photoelectric converter 110 may have a further configuration such as a passivation layer and an antireflection layer.
  • the photoelectric converter 110 has a plurality of translucent openings 114 penetrating the front and back surfaces.
  • the semiconductor substrate 111 functions as a photoelectric conversion substrate that absorbs incident light from the light receiving surface side to generate optical carriers (electrons and holes).
  • the semiconductor substrate 111 may have a pyramid-shaped fine uneven structure called a texture structure in order to improve the incident rate of light on the surface.
  • the semiconductor substrate 111 can be formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. It may also be formed from other semiconductor materials such as gallium arsenide (GaAs).
  • the semiconductor substrate 111 can be, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. Examples of the n-type dopant include phosphorus (P). Since crystalline silicon is used as the material of the semiconductor substrate 111, a relatively high output (stable output regardless of the illuminance) can be obtained even when the dark current is relatively small and the intensity of the incident light is low.
  • the first semiconductor layer 112 and the second semiconductor layer 113 collect charges of different polarities by attracting carriers having different polarities from the inside of the semiconductor substrate 111.
  • the semiconductor substrate 111 is n-type
  • the first semiconductor layer 112 may be formed of a p-type semiconductor
  • the second semiconductor layer 113 may be formed of an n-type semiconductor.
  • the first semiconductor layer 112 and the second semiconductor layer 113 can be formed of, for example, an amorphous silicon material containing a dopant that imparts a desired conductive type.
  • Examples of the p-type dopant include boron (B), and examples of the n-type dopant include phosphorus (P) described above.
  • the first semiconductor layer 112 and the second semiconductor layer 113 can be laminated on the semiconductor substrate 111, respectively, by a film forming technique such as CVD or PVD.
  • the translucent opening 114 makes it possible to transmit light to the back surface side of the solar cell 101 and collect light.
  • the translucent opening 114 can be formed by any method such as laser processing or etching processing.
  • the shape of the translucent opening 114 in a plan view, that is, the cross-sectional shape is typically circular, but can be any shape such as an elliptical shape and a polygonal shape.
  • the translucent opening 114 is preferably formed so as to be dispersed over substantially the entire photoelectric converter 110.
  • the translucent opening 114 is provided in a peripheral portion of the photoelectric converter 110, a band-shaped region crossing the photoelectric converter 110, or the like. By not providing it, the strength of the photoelectric converter 110 may be secured.
  • the translucent apertures 114 are regularly arranged so as to collect light evenly and improve the aesthetic appearance.
  • a plurality of translucent openings 114 are arranged in six directions so that six translucent openings 114 are adjacent to one translucent opening 114 at equal intervals in the circumferential direction and at equal distances.
  • the translucent openings 114 may be formed in a square arrangement in which the translucent openings 114 are arranged vertically and horizontally.
  • the area ratio of the translucent aperture 114 in the photoelectric converter 110 that is, the aperture ratio of the photoelectric converter 110 can be, for example, 3% or more and 50% or less, preferably 5% or more and 30% or less. As a result, sufficient light can pass through the solar cell 101, and a relatively large amount of electric power can be obtained.
  • the average diameter (diameter equivalent to a circle) of the translucent opening 114 can be, for example, 1 mm or more and 10 mm or less, preferably 2 mm or more and 8 mm or less. As a result, sufficient daylighting becomes possible while increasing the photoelectric conversion efficiency in the region other than the translucent aperture 114 of the solar cell 101.
  • the surface electrode 120 takes out the carriers attracted by the first semiconductor layer 112 as electric charges.
  • the surface electrode 120 is preferably made of a conductive material and preferably made of a metal having a low electrical resistance.
  • the surface electrode 120 can be formed by etching a metal layer laminated on the photoelectric converter 110, printing a conductive paste such as silver paste on the photoelectric converter 110, and firing. Further, the surface electrode 120 may have a multilayer structure.
  • the surface electrode 120 preferably has a small area so that light can be incident on the photoelectric conversion body 110, but in order to reduce the moving distance of carriers in the photoelectric conversion body 110 and improve the photoelectric conversion efficiency. It is preferable to provide it on the entire photoelectric converter 110. Therefore, it is preferable that the surface electrode 120 is formed in a net shape over the entire surface of the photoelectric converter 110.
  • the surface electrode 120 has a plurality of surrounding portions 121 (a hexagonal portion surrounded by a double-chain line) that individually surrounds the plurality of translucent openings 114.
  • the plurality of surrounding portions 121 are connected to each other. Therefore, the surface electrode 120 may have a connecting portion for connecting a plurality of surrounding portions 121, or may be formed so that the surrounding portions 121 are in contact with each other, for example, at a corner portion as shown in the drawing, and the adjacent surrounding portions are adjacent to each other. 121 may share a part thereof.
  • the surface electrode 120 individually surrounds the translucent opening 114 and has a plurality of surrounding portions 121 connected to each other, the surface electrode 120 is not divided by the translucent opening 114, so that charges can be collected from the entire photoelectric converter 110. ..
  • the surrounding portion 121 is preferably formed from an electrode wire 122 having a substantially constant width in order to reduce the electric resistance while reducing the area.
  • the surrounding portion 121 has a polygonal shape so that the pattern of the surface electrode 120 can be efficiently arranged while being simplified. Further, in order to equalize the current flowing through the surface electrode 120, the length of each side of the surrounding portion 121 is constant, that is, the surrounding portion 121 has a polygonal shape having the same length of all sides. preferable. In particular, when the translucent opening 114 is circular, by forming the surrounding portion 121 into a regular polygonal shape, it is possible to effectively suppress the variation in the moving distance of the carrier and prevent the current flowing through the surface electrode 120 from being biased. ..
  • each side of the surrounding portion 121 is arranged so that the distance (shortest distance) from the translucent opening 114 is substantially equal.
  • the minimum value of the distance from the translucent opening 114 of each side of the surrounding portion 121 is preferably 50% or more, and more preferably 55% or more of the maximum value.
  • the surface electrode 120 of the present embodiment is composed of a plurality of electrode wires 122 arranged in parallel and at equal intervals, and has three sets of electrode wire groups 123, 124, 125 having different angles so as to intersect each other. In this way, by forming the surface electrode 120 with the three sets of electrode wire groups 123, 124, 125, the pattern of the surface electrode 120 can be simplified. Further, by forming the surface electrode 120 with a plurality of electrode wires 122 extending linearly, the effective length of the electric circuit can be made relatively short. By reducing the width of the electrode wire 122, the area where light is incident on the photoelectric converter 110 can be increased.
  • the angles of the electrode wire groups 123, 124, 125 are different every 60 °, and the intersection positions are evenly shifted so that the three sets of electrode wire groups 123, 124, 125 do not intersect at one point. Therefore, a regular hexagonal surrounding portion 121 is formed. That is, in the surface electrode 120 of the present embodiment, the surrounding portions 121 have a regular hexagonal shape that is in contact with each other at the vertices, and defines a triangular residual space that does not include the translucent opening 114 between the plurality of surrounding portions 121. Since the surface electrode 120 having such a configuration does not form a region where the moving distance of the carrier becomes large, the photoelectric conversion efficiency per effective area (area excluding the translucent opening 114) of the photoelectric converter 110 is improved. Can be done.
  • the total area inside the plurality of surrounding parts 121 is preferably 2.0 times or more and 5.0 times or less, and 2.5 times or more and 4.0 times or less the total area of the remaining space outside the plurality of surrounding parts. More preferred. As a result, the maximum moving distance of the carrier can be easily reduced, so that the photoelectric conversion efficiency of the solar cell 101 can be easily improved.
  • the distance between each side of the surrounding portion 121 and the translucent opening 114 is preferably 20% or more and 150% or less, and more preferably 30% or more and 125% or less of the diameter of the translucent opening 114.
  • the area of the surface electrode 120 in a plan view is preferably 1% or more and 50% or less, and more preferably 2% or more and 40% or less of the area of the semiconductor substrate 111 excluding the translucent opening 114. As a result, it is possible to secure a sufficient area that contributes to the photoelectric conversion of the semiconductor substrate 111 while efficiently recovering the carriers.
  • the back surface electrode 130 takes out the carriers attracted by the second semiconductor layer 113 as electric charges.
  • the back surface electrode 130 can be formed of the same material as the front surface electrode 120.
  • the back surface electrode 130 may be formed in a mesh shape having a plurality of surrounding portions individually surrounding the plurality of translucent openings 114, but it is necessary to transmit light except for the translucent openings 114. Therefore, it may be laminated on the entire back surface of the photoelectric converter 110.
  • the solar cell 101 is a see-through type solar cell that can collect light on the back surface by having a plurality of translucent openings 114.
  • the surface electrode 120 has a plurality of surrounding portions 121 individually surrounding the translucent opening 114, the solar cell 101 does not have a region where the carrier travel distance is large, so that the photoelectric conversion efficiency is high.
  • FIG. 13 is a schematic plan view of the solar cell 101A according to the second embodiment of the present invention.
  • the same components as those in the above-described embodiment may be designated by the same reference numerals and duplicate description may be omitted.
  • the solar cell 101A has a plate-shaped photoelectric converter 110 having a plurality of translucent openings 114 penetrating the front and back surfaces, a surface electrode 120A laminated on the surface of the photoelectric converter 110, and laminated on the back surface of the photoelectric converter 110. It is provided with a back surface electrode (not shown).
  • the surface electrode 120A has a plurality of regular hexagonal surrounding portions 121A that individually surround the plurality of translucent openings 114.
  • the surrounding portion 121A shares each side with the adjacent surrounding portion 121A. With such a configuration, the surface electrode 120A can be appropriately arranged even when the area ratio of the translucent opening 114 is increased.
  • the surface electrode 120A has a plurality of regular hexagonal surrounding portions 121A that individually surround the plurality of translucent openings 114.
  • the surrounding portion 121A shares each side with the adjacent surrounding portion 121A. With such a configuration, the surface electrode 120A can be appropriately arranged even when the area ratio of the translucent opening 114 is increased.
  • FIG. 14 is a schematic plan view of the solar cell 101B according to the third embodiment of the present invention.
  • the solar cell 101B includes a plate-shaped photoelectric converter 110B having a plurality of elliptical transparent openings 114B in a plan view penetrating the front and back, a surface electrode 120B laminated on the surface of the photoelectric converter 110B, and a photoelectric conversion.
  • a back surface electrode (not shown) laminated on the back surface of the body 110B is provided.
  • the surface electrode 120B has a plurality of diamond-shaped surrounding portions 121B that individually surround the plurality of translucent openings 114B.
  • the surrounding portion 121B shares each side with the adjacent surrounding portion 121B. In this way, the maximum moving distance of the carrier can be reduced by forming the surrounding portion 121B surrounding the elliptical transparent opening 114B in a plan view in a diamond shape.
  • FIG. 15 is a schematic plan view of the solar cell 101C according to the fourth embodiment of the present invention.
  • the solar cell 101C has a plate-shaped photoelectric converter 110C having a plurality of triangular translucent openings 114C in a plan view penetrating the front and back, a surface electrode 120C laminated on the surface of the photoelectric converter 110C, and a photoelectric conversion.
  • a back surface electrode (not shown) laminated on the back surface of the body 110C is provided.
  • the surface electrode 120B has a plurality of triangular surrounding portions 121C that individually surround the plurality of translucent openings 114C.
  • the plurality of surrounding portions 121C are connected to each other at each vertex, and a triangular residual space not including the translucent opening 114C is defined between the plurality of surrounding portions 121.
  • the solar cell according to the present invention may include additional components such as an antireflection film.
  • additional components such as an antireflection film.
  • a further conductive layer or the like connecting between the first electrode and the first semiconductor layer and between the second electrode and the second semiconductor layer may be provided.
  • the passivation layer may be omitted.
  • the first peripheral surface portion and the second peripheral surface portion of the translucent opening may only have a difference in surface texture due to a difference in the processing process. Therefore, the semiconductor substrate may be exposed as a whole on the inner peripheral surface of the translucent opening.
  • the semiconductor substrate on the first peripheral surface portion may be covered with only the passivation layer.
  • the passivation layer may be formed of an insulating silicon oxide film, a silicon nitride film, or the like.
  • the first peripheral surface portion is located on the light receiving surface side, but in the solar cell according to the invention, the second peripheral surface portion may be located on the light receiving surface side.
  • the annular groove may be formed after the first semiconductor layer and the second semiconductor layer are formed.
  • the resist material can be patterned at the same time by irradiating the laser beam with the resist material laminated on the entire surface of the first semiconductor layer to form the annular groove.
  • the passivation layer may be formed after the formation of the annular groove or the formation of the translucent opening, and an electrode penetrating the passivation layer may be formed by, for example, printing and firing of a conductive paste.
  • this electrode line collects charge from other electrode lines and is external. It may be possible to use it as a bus bar for outputting to.
  • the surface electrode may have a bus bar provided separately, and one electrode wire group is arranged so as to be connected vertically to the bus bar, and the thickness of the electrode wire of this electrode wire group is larger than that of the other electrode wire. You may. As a result, the electrical resistance from the point where the surface electrode collects the electric charge from the photoelectric converter to the bus bar can be reduced, and the photoelectric conversion efficiency of the entire solar cell can be improved.

Abstract

Provided is a see-through solar cell having high photoelectric conversion efficiency. A solar cell 1 according to an aspect of the present invention comprises: a semiconductor substrate 10 formed as a flat plate and having a plurality of light-transmitting openings 11 extending therethrough in a thickness direction thereof; a first semiconductor layer 20 stacked on one major surface side of the semiconductor substrate 10; a second semiconductor layer 30 stacked on another major surface side of the semiconductor substrate 10; a first electrode 60 stacked on the first semiconductor layer 20; and a second electrode 70 stacked on the second semiconductor layer 30. The inner circumferential surface of the light-transmitting openings 11 includes a first circumferential surface portion 12 positioned closer to the first semiconductor layer 20, and a second circumferential surface portion 13 positioned closer to the second semiconductor layer 30 and having a surface property different from that of the first circumferential surface portion 12.

Description

太陽電池セル及び太陽電池セル製造方法Solar cell and solar cell manufacturing method
　本発明は、太陽電池セル及び太陽電池セル製造方法に関する。 The present invention relates to a solar cell and a method for manufacturing a solar cell.
　クリーンなエネルギー源として、太陽電池の利用が広がっている。一般的な太陽電池は、光を遮断するために、窓等には設置することが控えられる。そこで、光を透過する開口を形成したシースルー型の太陽電池も検討されている。例として、特許文献１には、光の入射によりキャリアを生成するｎ型半導体の基材にｐ型半導体の膜を積層することによりキャリアを回収するｐｎ接合を形成した半導体基板に複数の開口を形成し、半導体基板の受光面に開口を避けるようフィンガー電極を配設した太陽電池が開示されている。特許文献１は、比較的安価に半導体基板に開口を形成する方法として、フッ化物を含有する電解液を用いたエッチングを行うことを提案している。 The use of solar cells is expanding as a clean energy source. In order to block light, general solar cells are not installed in windows or the like. Therefore, a see-through type solar cell having an opening through which light is transmitted is also being studied. As an example, in Patent Document 1, a plurality of openings are provided in a semiconductor substrate having a pn junction for recovering carriers by laminating a p-type semiconductor film on a base material of an n-type semiconductor that generates carriers by incident light. A solar cell formed and provided with a finger electrode so as to avoid an opening on a light receiving surface of a semiconductor substrate is disclosed. Patent Document 1 proposes etching using an electrolytic solution containing fluoride as a method for forming an opening in a semiconductor substrate at a relatively low cost.
特開２００２－２９９６７２号公報Japanese Unexamined Patent Publication No. 2002-299672
　太陽電池セルの半導体基板にエッチングによって開口を形成すると、開口の内周面においてキャリアの再結合が生じるため、光電変換効率が低下し得る。特に、開口率を大きくしようとすると、開口の内周面におけるキャリアの再結合が顕著となるため、光電変換効率の低下が大きくなる。また、光を透過するための開口を避けてフィンガー電極を配設すると、フィンガー電極の延在方向と平行に並ぶ開口の間に、フィンガー電極までの距離が比較的大きい領域が形成される。フィンガー電極までの距離が大きくなると、光によって励起されたキャリアがフィンガー電極に回収される前に再結合して消滅してしまうことで、光電変換効率が低くなるという不都合が生じる。そこで、本発明は、光電変換効率が高いシースルー型の太陽電池セル及び太陽電池セル製造方法を提供することを課題とする。 When an opening is formed in the semiconductor substrate of a solar cell by etching, carrier recombination occurs on the inner peripheral surface of the opening, so that the photoelectric conversion efficiency may decrease. In particular, when an attempt is made to increase the aperture ratio, carrier recombination on the inner peripheral surface of the aperture becomes remarkable, so that the photoelectric conversion efficiency is significantly reduced. Further, if the finger electrodes are arranged so as to avoid openings for transmitting light, a region having a relatively large distance to the finger electrodes is formed between the openings arranged in parallel with the extending direction of the finger electrodes. When the distance to the finger electrode is increased, the carriers excited by light are recombined and disappear before being recovered by the finger electrode, which causes a disadvantage that the photoelectric conversion efficiency is lowered. Therefore, it is an object of the present invention to provide a see-through type solar cell and a method for manufacturing a solar cell having high photoelectric conversion efficiency.
　本発明の一態様に係る太陽電池セルは、板状に形成され、厚み方向に貫通する複数の透光開口を有する半導体基板と、前記半導体基板の一方の主面側に積層される第１半導体層と、前記半導体基板の他方の主面側に積層される第２半導体層と、前記第１半導体層に積層される第１電極と、前記第２半導体層に積層される第２電極と、を備え、前記透光開口の内周面は、前記第１半導体層の側に位置する第１周面部と、前記第２半導体層の側に位置し、前記第１周面部と表面性状が異なる第２周面部と、を有する。 The solar cell according to one aspect of the present invention is a semiconductor substrate formed in a plate shape and having a plurality of translucent openings penetrating in the thickness direction, and a first semiconductor laminated on one main surface side of the semiconductor substrate. A layer, a second semiconductor layer laminated on the other main surface side of the semiconductor substrate, a first electrode laminated on the first semiconductor layer, and a second electrode laminated on the second semiconductor layer. The inner peripheral surface of the translucent opening is located on the side of the first peripheral surface portion located on the side of the first semiconductor layer and on the side of the second semiconductor layer, and the surface texture is different from that of the first peripheral surface portion. It has a second peripheral surface portion.
　上述の太陽電池セルでは、前記第１周面部において、前記半導体基板は前記第１半導体層によって被覆され、前記第２周面部において、前記半導体基板は露出してもよい。 In the above-mentioned solar cell, the semiconductor substrate may be covered with the first semiconductor layer on the first peripheral surface portion, and the semiconductor substrate may be exposed on the second peripheral surface portion.
　本発明の一態様に係る太陽電池セル製造方法は、半導体基板にレーザ光を照射することによって環状溝を形成する工程と、前記環状溝の底部のエッチング又は割断により前記半導体基板の前記環状溝の内側の領域を分離することによって、前記半導体基板に開口を形成する工程と、備える。 The method for manufacturing a solar cell according to one aspect of the present invention includes a step of forming an annular groove by irradiating a semiconductor substrate with laser light, and etching or cutting of the bottom of the annular groove to form the annular groove of the semiconductor substrate. A step of forming an opening in the semiconductor substrate by separating the inner region is provided.
　上述の太陽電池セル製造方法は、前記環状溝を形成する工程と前記開口を形成する工程との間に、前記半導体基板に成膜を行う工程をさらに備えてもよい。 The above-mentioned solar cell manufacturing method may further include a step of forming a film on the semiconductor substrate between the step of forming the annular groove and the step of forming the opening.
　本発明の別の態様に係る太陽電池セルは、半導体基板及び前記半導体基板に積層される半導体層を有し、且つ表裏に貫通する複数の透光開口を有する光電変換体と、前記光電変換体の表面に積層される表面電極と、前記光電変換体の裏面に積層される裏面電極と、を備え、前記表面電極は、前記複数の透光開口を個別に取り囲む複数の囲繞部を有する。 A solar cell according to another aspect of the present invention has a semiconductor substrate and a photoelectric converter having a semiconductor layer laminated on the semiconductor substrate and having a plurality of translucent openings penetrating the front and back surfaces, and the photoelectric converter. The front surface electrode comprises a front surface electrode laminated on the front surface of the photoelectric converter and a back surface electrode laminated on the back surface of the photoelectric conversion body, and the front surface electrode has a plurality of surrounding portions individually surrounding the plurality of translucent openings.
　上述の太陽電池セルにおいて、前記囲繞部は多角形状であってもよい。 In the above-mentioned solar cell, the surrounding portion may have a polygonal shape.
　上述の太陽電池セルにおいて、囲繞部の各辺の長さは一定であってもよい。 In the above-mentioned solar cell, the length of each side of the surrounding portion may be constant.
　上述の太陽電池セルにおいて、前記囲繞部の各辺と前記透光開口との距離の最小値は最大値の５０％以上であってもよい。 In the above-mentioned solar cell, the minimum value of the distance between each side of the surrounding portion and the translucent opening may be 50% or more of the maximum value.
　上述の太陽電池セルにおいて、前記囲繞部の各辺と前記透光開口との距離は前記透光開口の直径の２０％以上１５０％以下であってもよい。 In the above-mentioned solar cell, the distance between each side of the surrounding portion and the translucent opening may be 20% or more and 150% or less of the diameter of the translucent opening.
　上述の太陽電池セルにおいて、前記表面電極は、それぞれ平行且つ等間隔に配置される複数の電極線からなり、互いに交差するよう角度が異なる３組の電極線群を有してもよい。 In the above-mentioned solar cell, the surface electrodes are composed of a plurality of electrode wires arranged in parallel and at equal intervals, and may have three sets of electrode wire groups having different angles so as to intersect each other.
　上述の太陽電池セルにおいて、前記囲繞部は、頂点で互いに接する六角形状であり、間に前記透光開口を含まない三角形状のスペースを画定してもよい。 In the above-mentioned solar cell, the surrounding portions may have a hexagonal shape that touches each other at the vertices, and may define a triangular space that does not include the translucent opening between them.
　上述の太陽電池セルにおいて、前記複数の囲繞部の内側の面積は前記複数の囲繞部の外側の面積の２倍以上５倍以下であってもよい。 In the above-mentioned solar cell, the area inside the plurality of surrounding parts may be twice or more and five times or less the area outside the plurality of surrounding parts.
　上述の太陽電池セルにおいて、前記裏面電極は、前記複数の透光開口を個別に取り囲む複数の囲繞部を有してもよい。 In the above-mentioned solar cell, the back surface electrode may have a plurality of surrounding portions individually surrounding the plurality of translucent openings.
　本発明によれば、光電変換効率が高いシースルー型の太陽電池セル及び太陽電池セル製造方法を提供できる。 According to the present invention, it is possible to provide a see-through type solar cell and a method for manufacturing a solar cell having high photoelectric conversion efficiency.
本発明の一実施形態に係る太陽電池セルの部分平面図である。It is a partial plan view of the solar cell which concerns on one Embodiment of this invention. 図１の太陽電池セルのＸ－Ｘ線部分断面図である。FIG. 3 is a partial cross-sectional view taken along the line XX of the solar cell of FIG. 本発明の一実施形態に係る太陽電池セル製造方法の手順を示すフローチャートである。It is a flowchart which shows the procedure of the solar cell manufacturing method which concerns on one Embodiment of this invention. 図３の太陽電池セル製造方法の一工程を説明する部分断面図である。FIG. 3 is a partial cross-sectional view illustrating one step of the solar cell manufacturing method of FIG. 図３の太陽電池セル製造方法の図４の次の工程を説明する部分断面図である。It is a partial sectional view explaining the next process of FIG. 4 of the solar cell manufacturing method of FIG. 図３の太陽電池セル製造方法の図５の次の工程を説明する部分断面図である。It is a partial sectional view explaining the next process of FIG. 5 of the solar cell manufacturing method of FIG. 図３の太陽電池セル製造方法の図６の次の工程を説明する部分断面図である。It is a partial sectional view explaining the next process of FIG. 6 of the solar cell manufacturing method of FIG. 図３の太陽電池セル製造方法の図７の次の工程を説明する部分断面図である。It is a partial sectional view explaining the next process of FIG. 7 of the solar cell manufacturing method of FIG. 図３の太陽電池セル製造方法の図８の次の工程を説明する部分断面図である。It is a partial sectional view explaining the next process of FIG. 8 of the solar cell manufacturing method of FIG. 図９の工程を説明する部分平面図である。It is a partial plan view explaining the process of FIG. 本発明の第２実施形態に係る太陽電池セルの模式平面図である。It is a schematic plan view of the solar cell which concerns on 2nd Embodiment of this invention. 図１１の太陽電池セルのＹ－Ｙ線模式断面図である。FIG. 11 is a schematic cross-sectional view taken along the line YY of the solar cell of FIG. 本発明の第３実施形態に係る太陽電池セルの模式平面図である。It is a schematic plan view of the solar cell which concerns on 3rd Embodiment of this invention. 本発明の第４実施形態に係る太陽電池セルの模式平面図である。It is a schematic plan view of the solar cell which concerns on 4th Embodiment of this invention. 本発明の第５実施形態に係る太陽電池セルの模式平面図である。It is a schematic plan view of the solar cell which concerns on 5th Embodiment of this invention.
　以下、添付の図面を参照して本発明の各実施形態について説明する。なお、各図面において同一又は相当の部分に対しては同一の符号を附すこととする。また、簡略化のために、部材の図示、符号等を省略する場合もあるが、かかる場合、他の図面を参照するものとする。また、図面における種々部材の形状及び寸法は、便宜上、見やすいように調整されている。 Hereinafter, each embodiment of the present invention will be described with reference to the accompanying drawings. In addition, the same reference numerals are given to the same or corresponding parts in each drawing. Further, for the sake of simplification, illustrations, reference numerals, etc. of the members may be omitted, but in such cases, other drawings shall be referred to. Further, the shapes and dimensions of various members in the drawings are adjusted so as to be easy to see for convenience.
　図１は、本発明の第１実施形態に係る太陽電池セル１の部分平面図である。図２は、太陽電池セルの分断面図である。太陽電池セル１は、板状に形成される半導体基板１０と、半導体基板１０の一方の主面側（受光面側）に積層される第１半導体層２０と、半導体基板１０の他方の主面側に積層される第２半導体層３０と、半導体基板１０と第１半導体層２０の間に介在する第１パッシベーション層４０と、半導体基板１０と第２半導体層３０の間に介在する第２パッシベーション層５０と、第１半導体層２０に積層される第１電極６０と、第２半導体層３０に積層される第２電極７０と、を備える。 FIG. 1 is a partial plan view of the solar cell 1 according to the first embodiment of the present invention. FIG. 2 is a sectional view of a solar cell. The solar cell 1 has a semiconductor substrate 10 formed in a plate shape, a first semiconductor layer 20 laminated on one main surface side (light receiving surface side) of the semiconductor substrate 10, and the other main surface of the semiconductor substrate 10. The second semiconductor layer 30 laminated on the side, the first passion layer 40 interposed between the semiconductor substrate 10 and the first semiconductor layer 20, and the second passion intervening between the semiconductor substrate 10 and the second semiconductor layer 30. The layer 50 includes a first electrode 60 laminated on the first semiconductor layer 20, and a second electrode 70 laminated on the second semiconductor layer 30.
　半導体基板１０は、入射光を吸収して光キャリア（電子及び正孔）を生成する光電変換基板として機能する。半導体基板１０は、受光面に光の入射率を向上するために、テクスチャ構造と呼ばれるピラミッド型の微細な凹凸構造を有してもよい。 The semiconductor substrate 10 functions as a photoelectric conversion substrate that absorbs incident light and generates optical carriers (electrons and holes). The semiconductor substrate 10 may have a pyramid-shaped fine uneven structure called a texture structure in order to improve the incident rate of light on the light receiving surface.
　半導体基板１０は、単結晶シリコン又は多結晶シリコン等の結晶シリコン材料で形成することができる。また、半導体基板１０は、ガリウムヒ素（ＧａＡｓ）等の他の半導体材料から形成されてもよい。半導体基板１０は、例えば結晶シリコン材料にｎ型ドーパントがドープされたｎ型の半導体基板とすることができる。ｎ型ドーパントとしては、例えばリン（Ｐ）が挙げられる。半導体基板１０の材料として結晶シリコンが用いられることにより、暗電流が比較的に小さく、入射光の強度が低い場合であっても比較的高出力（照度によらず安定した出力）が得られる。 The semiconductor substrate 10 can be formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. Further, the semiconductor substrate 10 may be formed of another semiconductor material such as gallium arsenide (GaAs). The semiconductor substrate 10 can be, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. Examples of the n-type dopant include phosphorus (P). By using crystalline silicon as the material of the semiconductor substrate 10, relatively high output (stable output regardless of illuminance) can be obtained even when the dark current is relatively small and the intensity of the incident light is low.
　半導体基板１０は、厚み方向に貫通する複数の透光開口１１を有する。透光開口１１は、太陽電池セル１の裏面側（受光面と反対側）に光を透過して採光することを可能にする。透光開口１１の平面視での形状としては、典型的には円形とされるが、楕円形状、多角形状等、任意の形状とされてもよい。 The semiconductor substrate 10 has a plurality of translucent openings 11 penetrating in the thickness direction. The translucent opening 11 makes it possible to transmit light to the back surface side (opposite the light receiving surface) of the solar cell 1 and collect light. The shape of the translucent opening 11 in a plan view is typically circular, but may be any shape such as an elliptical shape and a polygonal shape.
　透光開口１１は、均等に採光するために、半導体基板１０の略全体に分散して形成されることが好ましいが、半導体基板１０の強度を確保するために、例えば半導体基板１０の周縁部、半導体基板１０を横断する帯状領域等に設けられないようにしてもよい。透光開口１１は、より均等に採光するとともに、美観を向上できるよう、規則的に配置されることが好ましい。 The translucent opening 11 is preferably formed so as to be dispersed over substantially the entire semiconductor substrate 10 in order to collect light evenly, but in order to secure the strength of the semiconductor substrate 10, for example, the peripheral portion of the semiconductor substrate 10. It may not be provided in a band-shaped region or the like that crosses the semiconductor substrate 10. It is preferable that the translucent apertures 11 are regularly arranged so as to collect light more evenly and improve the aesthetic appearance.
　半導体基板１０における透光開口１１の面積率、つまり半導体基板１０の開口率としては、例えば３％以上５０％以下、好ましくは５％以上３０％以下とすることができる。これにより、十分な光が太陽電池セル１を透過することができ、且つ比較的大きい電力を得ることができる。 The area ratio of the translucent opening 11 in the semiconductor substrate 10, that is, the opening ratio of the semiconductor substrate 10 can be, for example, 3% or more and 50% or less, preferably 5% or more and 30% or less. As a result, sufficient light can pass through the solar cell 1 and a relatively large amount of electric power can be obtained.
　透光開口１１の平均径（円相当径）としては、例えば１ｍｍ以上１０ｍｍ以下好ましくは２ｍｍ以上８ｍｍ以下とすることができる。これにより、太陽電池セル１の光電変換効率を大きくしながら、十分な採光が可能となる。 The average diameter (diameter equivalent to a circle) of the translucent opening 11 can be, for example, 1 mm or more and 10 mm or less, preferably 2 mm or more and 8 mm or less. As a result, sufficient daylighting becomes possible while increasing the photoelectric conversion efficiency of the solar cell 1.
　透光開口１１の内周面は、第１半導体層２０の側に位置する第１周面部１２と、第２半導体層３０の側に位置し、第１周面部１２と表面性状が異なる第２周面部１３と、を有する。なお、「表面性状」とは、微細な凹凸形状、表面の層構造、半導体基板１０の材料の酸化等の変成状態等を含む。 The inner peripheral surface of the translucent opening 11 is located on the side of the first peripheral surface portion 12 located on the side of the first semiconductor layer 20 and on the side of the second semiconductor layer 30, and has a second surface texture different from that of the first peripheral surface portion 12. It has a peripheral surface portion 13. The "surface texture" includes a fine uneven shape, a layered structure on the surface, a metamorphic state such as oxidation of the material of the semiconductor substrate 10, and the like.
　本実施形態において、透光開口１１の第１周面部１２は、例えばレーザ加工面であり、半導体基板１０の内周面に酸化物等を有し得る。また、第１周面部１２では、半導体基板１０が第１パッシベーション層４０及び第１半導体層２０によって被覆されている。一方、第２周面部１３では、半導体基板１０が露出している。 In the present embodiment, the first peripheral surface portion 12 of the translucent opening 11 is, for example, a laser-machined surface, and may have an oxide or the like on the inner peripheral surface of the semiconductor substrate 10. Further, in the first peripheral surface portion 12, the semiconductor substrate 10 is covered with the first passivation layer 40 and the first semiconductor layer 20. On the other hand, the semiconductor substrate 10 is exposed on the second peripheral surface portion 13.
　第１周面部１２は、第１パッシベーション層４０及び第１半導体層２０によって半導体基板１０が被覆されているため、半導体基板１０の内部に生じたキャリアの再結合を抑制することにより太陽電池セル１の光電変換効率を向上する。また、透光開口１１は、半導体基板１０を露出する第２周面部１３を有するため、第１半導体層２０と第２半導体層３０とを確実に絶縁することができる。つまり、透光開口１１の内周面がキャリアの再結合を抑制する第１周面部１２と、短絡を防止する第２周面部１３とを有することによって、太陽電池セル１は、高い光電変換効率を有する。 Since the semiconductor substrate 10 is covered with the first passivation layer 40 and the first semiconductor layer 20 in the first peripheral surface portion 12, the solar cell 1 by suppressing the recombination of carriers generated inside the semiconductor substrate 10. Improves photoelectric conversion efficiency. Further, since the translucent opening 11 has the second peripheral surface portion 13 that exposes the semiconductor substrate 10, the first semiconductor layer 20 and the second semiconductor layer 30 can be reliably insulated. That is, the inner peripheral surface of the translucent opening 11 has a first peripheral surface portion 12 that suppresses carrier recombination and a second peripheral surface portion 13 that prevents a short circuit, so that the solar cell 1 has high photoelectric conversion efficiency. Has.
　透光開口１１の内周面における第１周面部１２の面積率の下限としては、５０％が好ましく、６０％がより好ましい。一方、透光開口１１の内周面における第１周面部１２の面積率の上限としては、９５％が好ましく、９０％がより好ましい。透光開口１１の内周面における第１周面部１２の面積率を前記下限以上とすることによって、キャリアの再結合抑制効果を大きくできる。また、透光開口１１の内周面における第１周面部１２の面積率を前記上限以下とすることによって、確実に短絡を防止するために特段の加工精度が要求されない。 The lower limit of the area ratio of the first peripheral surface portion 12 on the inner peripheral surface of the translucent opening 11 is preferably 50%, more preferably 60%. On the other hand, as the upper limit of the area ratio of the first peripheral surface portion 12 on the inner peripheral surface of the translucent opening 11, 95% is preferable, and 90% is more preferable. By setting the area ratio of the first peripheral surface portion 12 on the inner peripheral surface of the translucent opening 11 to be equal to or higher than the lower limit, the effect of suppressing carrier recombination can be increased. Further, by setting the area ratio of the first peripheral surface portion 12 on the inner peripheral surface of the translucent opening 11 to be equal to or less than the upper limit, no special processing accuracy is required in order to surely prevent a short circuit.
　第１半導体層２０及び第２半導体層３０は、半導体基板１０の内部から、互いに極性が異なるキャリアを誘引することにより、異なる極性の電荷を収集する。具体的には、半導体基板１０がｎ型である場合、第１半導体層２０はｐ型半導体から形成され、第２半導体層３０はｎ型半導体から形成され得る。 The first semiconductor layer 20 and the second semiconductor layer 30 collect charges of different polarities by attracting carriers having different polarities from the inside of the semiconductor substrate 10. Specifically, when the semiconductor substrate 10 is n-type, the first semiconductor layer 20 may be formed of a p-type semiconductor, and the second semiconductor layer 30 may be formed of an n-type semiconductor.
　第１半導体層２０及び第２半導体層３０は、例えば所望の導電型を付与するドーパントを含有するアモルファスシリコン材料で形成することができる。ｐ型ドーパントとしては、例えばホウ素（Ｂ）が挙げられ、ｎ型ドーパントとしては、例えば上述したリン（Ｐ）が挙げられる。 The first semiconductor layer 20 and the second semiconductor layer 30 can be formed of, for example, an amorphous silicon material containing a dopant that imparts a desired conductive type. Examples of the p-type dopant include boron (B), and examples of the n-type dopant include phosphorus (P) described above.
　第１半導体層２０は、透光開口１１の内周面に延在し、第１周面部１２において、半導体基板１０の内周面を覆う。 The first semiconductor layer 20 extends to the inner peripheral surface of the translucent opening 11 and covers the inner peripheral surface of the semiconductor substrate 10 at the first peripheral surface portion 12.
　第１パッシベーション層４０及び第２パッシベーション層５０は、半導体基板１０の内部で生成したキャリアの半導体基板１０の表面での再結合を抑制することにより、太陽電池セル１の光電変換効率を向上する。第１パッシベーション層４０及び第２パッシベーション層５０は、アモルファスシリコンから形成される真性半導体層とすることができる。 The first passivation layer 40 and the second passivation layer 50 improve the photoelectric conversion efficiency of the solar cell 1 by suppressing the recombination of the carriers generated inside the semiconductor substrate 10 on the surface of the semiconductor substrate 10. The first passivation layer 40 and the second passivation layer 50 can be an intrinsic semiconductor layer formed of amorphous silicon.
　第１パッシベーション層４０は、透光開口１１の内周面に延在し、第１周面部１２において、半導体基板１０の内周面を覆う。 The first passivation layer 40 extends to the inner peripheral surface of the translucent opening 11 and covers the inner peripheral surface of the semiconductor substrate 10 at the first peripheral surface portion 12.
　第１電極６０及び第２電極７０は、第１半導体層２０及び第２半導体層３０が引き寄せたキャリアを電荷として取り出す。第１電極６０及び第２電極７０は、導電性を有する材料から形成され、電気抵抗が小さい金属を主体とすることが好ましい。具体例として、第１電極６０及び第２電極７０は、金属、銀ペースト等から形成することができる。 The first electrode 60 and the second electrode 70 take out the carriers attracted by the first semiconductor layer 20 and the second semiconductor layer 30 as electric charges. The first electrode 60 and the second electrode 70 are preferably made of a material having conductivity and mainly made of a metal having a small electric resistance. As a specific example, the first electrode 60 and the second electrode 70 can be formed of metal, silver paste, or the like.
　受光面側の第１電極６０は、半導体基板１０に光が入射できるよう面積を小さくするために、複数の線状に形成されることが好ましい。また、第１電極６０は、キャリアの移動距離が大きくなる領域を小さくするために、第１電極６０は網状に形成されてもよい。一方、第２電極７０は、第１電極６０と同じ形状に形成されてもよいが、第２電極７０までのキャリアの移動距離及び第２電極７０の中での電気抵抗を小さくするために、透光開口１１以外の領域の略全面に設けられ得る。 The first electrode 60 on the light receiving surface side is preferably formed in a plurality of linear shapes in order to reduce the area so that light can be incident on the semiconductor substrate 10. Further, the first electrode 60 may be formed in a mesh shape in order to reduce the region where the moving distance of the carrier becomes large. On the other hand, the second electrode 70 may be formed in the same shape as the first electrode 60, but in order to reduce the moving distance of the carrier to the second electrode 70 and the electric resistance in the second electrode 70, the second electrode 70 may be formed. It may be provided on substantially the entire surface of a region other than the translucent opening 11.
　以上のように、太陽電池セル１は、透光開口１１の内周面がキャリアの再結合を抑制する第１周面部１２と短絡を防止する第２周面部１３と、を有することによって、高い光電変換効率を実現できる。 As described above, the solar cell 1 is high because the inner peripheral surface of the translucent opening 11 has a first peripheral surface portion 12 that suppresses carrier recombination and a second peripheral surface portion 13 that prevents a short circuit. Photoelectric conversion efficiency can be achieved.
　太陽電池セル１は、本発明に係る太陽電池セル製造方法の一実施形態によって製造することができる。本実施形態の太陽電池セル製造方法は、図３に示すように、環状溝形成工程（ステップＳ１）と、パッシベーション層成膜工程（ステップＳ２）と、第１半導体層成膜工程（ステップＳ３）と、第２半導体層成膜工程（ステップＳ４）と、第１電極形成工程（ステップＳ５）と、第２電極形成工程（ステップＳ６）と、透光開口形成工程（ステップＳ７）と、を備える。 The solar cell 1 can be manufactured by one embodiment of the solar cell manufacturing method according to the present invention. As shown in FIG. 3, the solar cell cell manufacturing method of the present embodiment includes an annular groove forming step (step S1), a passage layer forming step (step S2), and a first semiconductor layer forming step (step S3). A second semiconductor layer film forming step (step S4), a first electrode forming step (step S5), a second electrode forming step (step S6), and a translucent opening forming step (step S7) are provided. ..
　ステップＳ１の環状溝形成工程では、半導体基板１０の一方の面にレーザ光を照射することにより、図４に示すように、透光開口１１の外径に対応する環状溝Ｇを形成する。最終的に、環状溝Ｇの外側の内周面が第１周面部１２となる。このため、環状溝Ｇの平面形状は、透光開口１１の外形に対応する無端ループ状であり、円形に限られない。環状溝Ｇの深さは、第１周面部１２の高さ対応して定められる。環状溝Ｇの内面には、パッシベーション層成膜工程及び第１半導体層成膜工程において成膜が行われる。このため、環状溝Ｇの幅は、環状溝Ｇの奥部まで成膜ガスを供給できるような幅とされる。 In the annular groove forming step of step S1, by irradiating one surface of the semiconductor substrate 10 with a laser beam, an annular groove G corresponding to the outer diameter of the translucent opening 11 is formed as shown in FIG. Finally, the inner peripheral surface on the outer side of the annular groove G becomes the first peripheral surface portion 12. Therefore, the planar shape of the annular groove G is an endless loop shape corresponding to the outer shape of the translucent opening 11, and is not limited to a circular shape. The depth of the annular groove G is determined corresponding to the height of the first peripheral surface portion 12. A film is formed on the inner surface of the annular groove G in the passivation layer film forming step and the first semiconductor layer film forming step. Therefore, the width of the annular groove G is set so that the film-forming gas can be supplied to the inner part of the annular groove G.
　ステップＳ２のパッシベーション層成膜工程では、図５に示すように、半導体基板１０の両面及び環状溝Ｇの内面に、第１パッシベーション層４０及び第２パッシベーション層５０を形成する材料を積層する。第１パッシベーション層４０及び第２パッシベーション層５０は、例えばＣＶＤ、ＰＶＤ等の成膜技術によって形成することができる。このパッシベーション層成膜工程は、半導体基板１０の片面ずつ、２回に分けて行ってもよい。 In the passivation layer film forming step of step S2, as shown in FIG. 5, the materials forming the first passivation layer 40 and the second passivation layer 50 are laminated on both sides of the semiconductor substrate 10 and the inner surface of the annular groove G. The first passivation layer 40 and the second passivation layer 50 can be formed by, for example, a film forming technique such as CVD or PVD. This passivation layer film forming step may be performed in two steps for each side of the semiconductor substrate 10.
　ステップＳ３の第１半導体層成膜工程では、図６に示すように、半導体基板１０の受光側の主面及び環状溝Ｇの内面の第１パッシベーション層４０の表面に、第１半導体層２０を形成する材料を積層する。第１半導体層２０も、第１パッシベーション層４０及び第２パッシベーション層５０と同様に、例えばＣＶＤ、ＰＶＤ等の成膜技術によって形成することができる。 In the first semiconductor layer film forming step of step S3, as shown in FIG. 6, the first semiconductor layer 20 is formed on the surface of the first passivation layer 40 on the main surface of the semiconductor substrate 10 on the light receiving side and the inner surface of the annular groove G. Laminate the materials to be formed. The first semiconductor layer 20 can also be formed by, for example, a film forming technique such as CVD or PVD, like the first passivation layer 40 and the second passivation layer 50.
　ステップＳ４の第２半導体層成膜工程では、図７に示すように、半導体基板１０の受光面と反対側の主面の第２パッシベーション層５０の表面に、第２半導体層３０を形成する材料を積層する。第２半導体層３０も、例えばＣＶＤ、ＰＶＤ等の成膜技術によって形成することができる。 In the second semiconductor layer film forming step of step S4, as shown in FIG. 7, a material for forming the second semiconductor layer 30 on the surface of the second passivation layer 50 on the main surface opposite to the light receiving surface of the semiconductor substrate 10. Are laminated. The second semiconductor layer 30 can also be formed by, for example, a film forming technique such as CVD or PVD.
　ステップＳ５の第１電極形成工程では、図８に示すように、例えば導電性ペーストの印刷及び焼成、金属層の積層及びレジストパターン用いた金属層のエッチング等の方法により、第１電極６０を形成する。 In the first electrode forming step of step S5, as shown in FIG. 8, the first electrode 60 is formed by, for example, printing and firing of a conductive paste, laminating of a metal layer, and etching of a metal layer using a resist pattern. do.
　ステップＳ６の第２電極形成工程では、図９に示すように、例えば導電性ペーストの印刷及び焼成、金属層の積層及びレジストパターン用いた金属層のエッチング等の方法により、第２電極７０を形成する。第２電極形成工程における焼成又はエッチングは、第１電極形成工程における焼成又はエッチングと同時に行ってもよい。 In the second electrode forming step of step S6, as shown in FIG. 9, the second electrode 70 is formed by, for example, printing and firing of a conductive paste, laminating of a metal layer, and etching of a metal layer using a resist pattern. do. The firing or etching in the second electrode forming step may be performed at the same time as the firing or etching in the first electrode forming step.
　このように、環状溝Ｇを形成した半導体基板１０に成膜を行うことによって、図９及び１０に示すように、太陽電池セル１の透光開口１１となるべき部分（環状溝Ｇ及びその内側）にも、半導体基板１０、第１半導体層２０、第２半導体層３０、第１パッシベーション層４０及び第２パッシベーション層５０が存在する中間製品が得られる。 By forming a film on the semiconductor substrate 10 on which the annular groove G is formed in this way, as shown in FIGS. 9 and 10, a portion to be a translucent opening 11 of the solar cell 1 (annular groove G and its inner side). ) Also, an intermediate product having a semiconductor substrate 10, a first semiconductor layer 20, a second semiconductor layer 30, a first passivation layer 40, and a second passivation layer 50 can be obtained.
　ステップＳ７の透光開口形成工程では、環状溝Ｇの底部のエッチング又は割断により、半導体基板１０の環状溝Ｇの内側の領域を分離することによって、透光開口１１を形成する。これにより、図１に示す太陽電池セル１が得られる。 In the translucent opening forming step of step S7, the translucent opening 11 is formed by separating the inner region of the annular groove G of the semiconductor substrate 10 by etching or cutting the bottom of the annular groove G. As a result, the solar cell 1 shown in FIG. 1 is obtained.
　環状溝Ｇの底部をエッチングする場合、第１半導体層２０の全面を覆うレジストパターンと、第２半導体層３０の透光開口１１を形成する領域の少なくとも環状溝Ｇに対応する部分を開口するレジストパターンとを形成することで、環状溝Ｇの内側の領域を分離できる。 When the bottom of the annular groove G is etched, a resist pattern that covers the entire surface of the first semiconductor layer 20 and a resist that opens at least a portion corresponding to at least the annular groove G in the region forming the translucent opening 11 of the second semiconductor layer 30. By forming the pattern, the region inside the annular groove G can be separated.
　環状溝Ｇの底部を割断する場合、環状溝Ｇの内側に対応する部分に突起を有する治具を圧接することで、環状溝Ｇの内側の領域を分離できる。 When cutting the bottom of the annular groove G, the inner region of the annular groove G can be separated by pressing a jig having a protrusion on the portion corresponding to the inside of the annular groove G.
　このように、環状溝形成工程と透光開口形成工程との２段階に分けて透光開口１１を形成することによって、透光開口１１が表面性状の異なる第１周面部１２と第２周面部１３とを有するものとなる。特に、環状溝形成工程と透光開口形成工程との間に半導体基板１０に成膜を行う工程を備えることによって、キャリアの再結合を抑制する第１周面部１２と短絡を防止する第２周面部１３とを確実に形成できるため、高い光電変換効率を有する太陽電池セル１が比較的容易に製造される。 In this way, by forming the translucent opening 11 in two stages of the annular groove forming step and the translucent opening forming step, the translucent opening 11 has different surface textures of the first peripheral surface portion 12 and the second peripheral surface portion. It will have 13 and. In particular, by providing a step of forming a film on the semiconductor substrate 10 between the annular groove forming step and the translucent opening forming step, the first peripheral surface portion 12 that suppresses carrier recombination and the second circumference that prevents a short circuit are prevented. Since the surface portion 13 can be reliably formed, the solar cell 1 having high photoelectric conversion efficiency can be manufactured relatively easily.
＜第２実施形態＞
　図１１は、本発明の第１実施形態に係る太陽電池セル１０１の模式平面図である。図１２は、太陽電池セル１０１の模式断面図である。太陽電池セル１０１は、板状の光電変換体１１０と、光電変換体１１０の表面に積層される表面電極１２０と、光電変換体１１０の裏面に積層される裏面電極１３０と、を備える。なお、本明細書において、太陽電池セル１０１の使用状態において、光が入射する側の面を表面、その反対側を裏面という。 <Second Embodiment>
FIG. 11 is a schematic plan view of the solar cell 101 according to the first embodiment of the present invention. FIG. 12 is a schematic cross-sectional view of the solar cell 101. The solar cell 101 includes a plate-shaped photoelectric converter 110, a front electrode 120 laminated on the surface of the photoelectric converter 110, and a back surface electrode 130 laminated on the back surface of the photoelectric converter 110. In the present specification, in the state of use of the solar cell 101, the surface on the side where light is incident is referred to as the front surface, and the opposite side thereof is referred to as the back surface.
　光電変換体１１０は、半導体基板１１１と、半導体基板１１１の表面に積層される第１半導体層１１２と、半導体基板１１１の裏面に積層される第２半導体層１１３とを有する。光電変換体１１０は、図示しないが、例えばパッシベーション層、反射防止層等のさらなる構成を有してもよい。また、光電変換体１１０は、表裏に貫通する複数の透光開口１１４を有する。 The photoelectric converter 110 has a semiconductor substrate 111, a first semiconductor layer 112 laminated on the surface of the semiconductor substrate 111, and a second semiconductor layer 113 laminated on the back surface of the semiconductor substrate 111. Although not shown, the photoelectric converter 110 may have a further configuration such as a passivation layer and an antireflection layer. Further, the photoelectric converter 110 has a plurality of translucent openings 114 penetrating the front and back surfaces.
　半導体基板１１１は、受光面側からの入射光を吸収して光キャリア（電子及び正孔）を生成する光電変換基板として機能する。半導体基板１１１は、表面に光の入射率を向上するために、テクスチャ構造と呼ばれるピラミッド型の微細な凹凸構造を有してもよい。 The semiconductor substrate 111 functions as a photoelectric conversion substrate that absorbs incident light from the light receiving surface side to generate optical carriers (electrons and holes). The semiconductor substrate 111 may have a pyramid-shaped fine uneven structure called a texture structure in order to improve the incident rate of light on the surface.
　半導体基板１１１は、単結晶シリコン又は多結晶シリコン等の結晶シリコン材料で形成することができる。また、ガリウムヒ素（ＧａＡｓ）等の他の半導体材料から形成されてもよい。半導体基板１１１は、例えば結晶シリコン材料にｎ型ドーパントがドープされたｎ型の半導体基板とすることができる。ｎ型ドーパントとしては、例えばリン（Ｐ）が挙げられる。半導体基板１１１の材料として結晶シリコンが用いられることにより、暗電流が比較的に小さく、入射光の強度が低い場合であっても比較的高出力（照度によらず安定した出力）が得られる。 The semiconductor substrate 111 can be formed of a crystalline silicon material such as single crystal silicon or polycrystalline silicon. It may also be formed from other semiconductor materials such as gallium arsenide (GaAs). The semiconductor substrate 111 can be, for example, an n-type semiconductor substrate in which a crystalline silicon material is doped with an n-type dopant. Examples of the n-type dopant include phosphorus (P). Since crystalline silicon is used as the material of the semiconductor substrate 111, a relatively high output (stable output regardless of the illuminance) can be obtained even when the dark current is relatively small and the intensity of the incident light is low.
　第１半導体層１１２及び第２半導体層１１３は、半導体基板１１１の内部から、互いに極性が異なるキャリアを誘引することにより、異なる極性の電荷を収集する。具体的には、半導体基板１１１がｎ型である場合、第１半導体層１１２はｐ型半導体から形成され、第２半導体層１１３はｎ型半導体から形成され得る。 The first semiconductor layer 112 and the second semiconductor layer 113 collect charges of different polarities by attracting carriers having different polarities from the inside of the semiconductor substrate 111. Specifically, when the semiconductor substrate 111 is n-type, the first semiconductor layer 112 may be formed of a p-type semiconductor, and the second semiconductor layer 113 may be formed of an n-type semiconductor.
　第１半導体層１１２及び第２半導体層１１３は、例えば所望の導電型を付与するドーパントを含有するアモルファスシリコン材料で形成することができる。ｐ型ドーパントとしては、例えばホウ素（Ｂ）が挙げられ、ｎ型ドーパントとしては、例えば上述したリン（Ｐ）が挙げられる。第１半導体層１１２及び第２半導体層１１３は、例えばＣＶＤ、ＰＶＤ等の成膜技術によって、半導体基板１１１にそれぞれ積層され得る。 The first semiconductor layer 112 and the second semiconductor layer 113 can be formed of, for example, an amorphous silicon material containing a dopant that imparts a desired conductive type. Examples of the p-type dopant include boron (B), and examples of the n-type dopant include phosphorus (P) described above. The first semiconductor layer 112 and the second semiconductor layer 113 can be laminated on the semiconductor substrate 111, respectively, by a film forming technique such as CVD or PVD.
　透光開口１１４は、太陽電池セル１０１の裏面側に光を透過して採光することを可能にする。透光開口１１４は、例えばレーザ加工、エッチング加工等、任意の方法で形成することができる。透光開口１１４の平面視での形状つまり断面形状としては、典型的には円形とされるが、楕円形状、多角形状等、任意の形状とすることができる。 The translucent opening 114 makes it possible to transmit light to the back surface side of the solar cell 101 and collect light. The translucent opening 114 can be formed by any method such as laser processing or etching processing. The shape of the translucent opening 114 in a plan view, that is, the cross-sectional shape is typically circular, but can be any shape such as an elliptical shape and a polygonal shape.
　透光開口１１４は、光電変換体１１０の略全体に分散して形成されることが好ましいが、例えば光電変換体１１０の周縁部、光電変換体１１０を横断する帯状領域等に透光開口１１４を設けないようにすることで、光電変換体１１０の強度と確保してもよい。透光開口１１４は、均等に採光するとともに、美観を向上できるよう、規則的に配置されることが好ましい。図示する例では、１つの透光開口１１４に周方向に等間隔且つ等距離に６つの透光開口１１４が隣接するよう、複数の透光開口１１４が六方配置されているが、透光開口１１４は例えば透光開口１１４が縦横に並んだ正方配置に形成されてもよい。 The translucent opening 114 is preferably formed so as to be dispersed over substantially the entire photoelectric converter 110. For example, the translucent opening 114 is provided in a peripheral portion of the photoelectric converter 110, a band-shaped region crossing the photoelectric converter 110, or the like. By not providing it, the strength of the photoelectric converter 110 may be secured. It is preferable that the translucent apertures 114 are regularly arranged so as to collect light evenly and improve the aesthetic appearance. In the illustrated example, a plurality of translucent openings 114 are arranged in six directions so that six translucent openings 114 are adjacent to one translucent opening 114 at equal intervals in the circumferential direction and at equal distances. For example, the translucent openings 114 may be formed in a square arrangement in which the translucent openings 114 are arranged vertically and horizontally.
　光電変換体１１０における透光開口１１４の面積率、つまり光電変換体１１０の開口率としては、例えば３％以上５０％以下、好ましくは５％以上３０％以下とすることができる。これにより、十分な光が太陽電池セル１０１を透過することができ、且つ比較的大きい電力を得ることができる。 The area ratio of the translucent aperture 114 in the photoelectric converter 110, that is, the aperture ratio of the photoelectric converter 110 can be, for example, 3% or more and 50% or less, preferably 5% or more and 30% or less. As a result, sufficient light can pass through the solar cell 101, and a relatively large amount of electric power can be obtained.
　透光開口１１４の平均径（円相当径）としては、例えば１ｍｍ以上１０ｍｍ以下好ましくは２ｍｍ以上８ｍｍ以下とすることができる。これにより、太陽電池セル１０１の透光開口１１４以外の領域における光電変換効率を大きくしながら、十分な採光が可能となる。 The average diameter (diameter equivalent to a circle) of the translucent opening 114 can be, for example, 1 mm or more and 10 mm or less, preferably 2 mm or more and 8 mm or less. As a result, sufficient daylighting becomes possible while increasing the photoelectric conversion efficiency in the region other than the translucent aperture 114 of the solar cell 101.
　表面電極１２０は、第１半導体層１１２が引き寄せたキャリアを電荷として取り出す。表面電極１２０は、導電性を有する材料から形成され、電気抵抗が小さい金属から形成されることが好ましい。具体的には、表面電極１２０は、光電変換体１１０に積層した金属層のエッチング、光電変換体１１０への銀ペーストのような導電性ペーストの印刷及び焼成等の方法で形成することができる。また、表面電極１２０は、多層構造を有してもよい。 The surface electrode 120 takes out the carriers attracted by the first semiconductor layer 112 as electric charges. The surface electrode 120 is preferably made of a conductive material and preferably made of a metal having a low electrical resistance. Specifically, the surface electrode 120 can be formed by etching a metal layer laminated on the photoelectric converter 110, printing a conductive paste such as silver paste on the photoelectric converter 110, and firing. Further, the surface electrode 120 may have a multilayer structure.
　表面電極１２０は、光電変換体１１０に光が入射できるよう、面積を小さくすることが好ましいが、光電変換体１１０の中でのキャリアの移動距離を小さくして光電変換効率を向上するために、光電変換体１１０の全体に設けることが好ましい。このため、表面電極１２０は、光電変換体１１０の表面全域に網状に形成されることが好ましい。 The surface electrode 120 preferably has a small area so that light can be incident on the photoelectric conversion body 110, but in order to reduce the moving distance of carriers in the photoelectric conversion body 110 and improve the photoelectric conversion efficiency. It is preferable to provide it on the entire photoelectric converter 110. Therefore, it is preferable that the surface electrode 120 is formed in a net shape over the entire surface of the photoelectric converter 110.
　表面電極１２０は、複数の透光開口１１４を個別に取り囲む複数の囲繞部１２１（二鎖線で取り囲んだ六角形状の部分）を有する。表面電極１２０において、複数の囲繞部１２１は、互いに接続される。このため、表面電極１２０は、複数の囲繞部１２１を接続する接続部を有してもよく、囲繞部１２１同士が図示するように例えば角部で接するよう形成されてもよく、隣接する囲繞部１２１がその一部を共有してもよい。 The surface electrode 120 has a plurality of surrounding portions 121 (a hexagonal portion surrounded by a double-chain line) that individually surrounds the plurality of translucent openings 114. In the surface electrode 120, the plurality of surrounding portions 121 are connected to each other. Therefore, the surface electrode 120 may have a connecting portion for connecting a plurality of surrounding portions 121, or may be formed so that the surrounding portions 121 are in contact with each other, for example, at a corner portion as shown in the drawing, and the adjacent surrounding portions are adjacent to each other. 121 may share a part thereof.
　表面電極１２０は、透光開口１１４を個別に取り囲み、互いに接続される複数の囲繞部１２１を有するため、透光開口１１４よって分断されないので、光電変換体１１０の全体から電荷を収集することができる。 Since the surface electrode 120 individually surrounds the translucent opening 114 and has a plurality of surrounding portions 121 connected to each other, the surface electrode 120 is not divided by the translucent opening 114, so that charges can be collected from the entire photoelectric converter 110. ..
　囲繞部１２１は、面積を小さくしつつ電気抵抗を小さくするために略一定の幅を有する電極線１２２から形成されることが好ましい。 The surrounding portion 121 is preferably formed from an electrode wire 122 having a substantially constant width in order to reduce the electric resistance while reducing the area.
　囲繞部１２１は、表面電極１２０のパターンを簡素化しつつ効率よく配置できるよう多角形状であることが好ましい。また、表面電極１２０を流れる電流を均等化するために、囲繞部１２１の各辺の長さが一定であること、つまり囲繞部１２１が全ての辺の長さが等しい多角形状であることがより好ましい。特に透光開口１１４が円形である場合、囲繞部１２１を正多角形状に形成することによって、キャリアの移動距離のバラツキを効果的に抑制すると共に、表面電極１２０を流れる電流が偏ることを防止できる。 It is preferable that the surrounding portion 121 has a polygonal shape so that the pattern of the surface electrode 120 can be efficiently arranged while being simplified. Further, in order to equalize the current flowing through the surface electrode 120, the length of each side of the surrounding portion 121 is constant, that is, the surrounding portion 121 has a polygonal shape having the same length of all sides. preferable. In particular, when the translucent opening 114 is circular, by forming the surrounding portion 121 into a regular polygonal shape, it is possible to effectively suppress the variation in the moving distance of the carrier and prevent the current flowing through the surface electrode 120 from being biased. ..
　囲繞部１２１の各辺は、透光開口１１４からの距離（最短距離）が略等しくなるよう配置されることが好ましい。具体的には、囲繞部１２１の各辺の透光開口１１４からの距離の最小値が最大値の５０％以上であることが好ましく、５５％以上であることがより好ましい。これにより、キャリアの移動距離が局所的に大きくなることを防止できる。囲繞部１２１の重心を透光開口１１４の重心と略一致させることによって、囲繞部１２１の各辺の透光開口１１４からの距離を均等化できる。 It is preferable that each side of the surrounding portion 121 is arranged so that the distance (shortest distance) from the translucent opening 114 is substantially equal. Specifically, the minimum value of the distance from the translucent opening 114 of each side of the surrounding portion 121 is preferably 50% or more, and more preferably 55% or more of the maximum value. As a result, it is possible to prevent the moving distance of the carrier from increasing locally. By substantially matching the center of gravity of the surrounding portion 121 with the center of gravity of the translucent opening 114, the distance from each side of the surrounding portion 121 from the translucent opening 114 can be equalized.
　本実施形態の表面電極１２０は、それぞれ平行且つ等間隔に配置される複数の電極線１２２からなり、互いに交差するよう角度が異なる３組の電極線群１２３，１２４，１２５を有する。このように、３組の電極線群１２３，１２４，１２５によって表面電極１２０を構成することで、表面電極１２０のパターンを簡素化できる。また、直線的に延びる複数の電極線１２２によって表面電極１２０を構成することで、実効的な電路の長さを比較的短くすることができる。このような電極線１２２の幅を小さくすることによって光電変換体１１０に光が入射する面積を大きくできる。 The surface electrode 120 of the present embodiment is composed of a plurality of electrode wires 122 arranged in parallel and at equal intervals, and has three sets of electrode wire groups 123, 124, 125 having different angles so as to intersect each other. In this way, by forming the surface electrode 120 with the three sets of electrode wire groups 123, 124, 125, the pattern of the surface electrode 120 can be simplified. Further, by forming the surface electrode 120 with a plurality of electrode wires 122 extending linearly, the effective length of the electric circuit can be made relatively short. By reducing the width of the electrode wire 122, the area where light is incident on the photoelectric converter 110 can be increased.
　特に、本実施形態では、電極線群１２３，１２４，１２５の角度を６０°毎に異ならせ、３組の電極線群１２３，１２４，１２５が一点で交差しないように均等に交差位置をずらすことで、正六角形状の囲繞部１２１を形成する。つまり、本実施形態の表面電極１２０において、囲繞部１２１は、頂点で互いに接する正六角形状であり、複数の囲繞部１２１の間に透光開口１１４を含まない三角形状の残余スペースを画定する。このような構成を有する表面電極１２０は、キャリアの移動距離が大きくなる領域を形成しないので、光電変換体１１０の有効面積（透光開口１１４を除外した面積）当たりの光電変換効率を向上することができる。 In particular, in the present embodiment, the angles of the electrode wire groups 123, 124, 125 are different every 60 °, and the intersection positions are evenly shifted so that the three sets of electrode wire groups 123, 124, 125 do not intersect at one point. Therefore, a regular hexagonal surrounding portion 121 is formed. That is, in the surface electrode 120 of the present embodiment, the surrounding portions 121 have a regular hexagonal shape that is in contact with each other at the vertices, and defines a triangular residual space that does not include the translucent opening 114 between the plurality of surrounding portions 121. Since the surface electrode 120 having such a configuration does not form a region where the moving distance of the carrier becomes large, the photoelectric conversion efficiency per effective area (area excluding the translucent opening 114) of the photoelectric converter 110 is improved. Can be done.
　複数の囲繞部１２１の内側の合計面積としては、複数の囲繞部の外側の残余スペースの合計面積の２．０倍以上５．０倍以下が好ましく、２．５倍以上４．０倍以下がより好ましい。これにより、キャリアの最大移動距離を容易に小さくできるので、太陽電池セル１０１の光電変換効率を容易に向上することができる。 The total area inside the plurality of surrounding parts 121 is preferably 2.0 times or more and 5.0 times or less, and 2.5 times or more and 4.0 times or less the total area of the remaining space outside the plurality of surrounding parts. More preferred. As a result, the maximum moving distance of the carrier can be easily reduced, so that the photoelectric conversion efficiency of the solar cell 101 can be easily improved.
　囲繞部１２１の各辺と透光開口１１４の距離としては、透光開口１１４の直径の２０％以上１５０％以下が好ましく、３０％以上１２５％以下がより好ましい。これにより、太陽電池セル１０１の光電変換効率を向上しつつ、採光性を確保できる。 The distance between each side of the surrounding portion 121 and the translucent opening 114 is preferably 20% or more and 150% or less, and more preferably 30% or more and 125% or less of the diameter of the translucent opening 114. As a result, the daylighting property can be ensured while improving the photoelectric conversion efficiency of the solar cell 101.
　平面視における表面電極１２０の面積としては、半導体基板１１１の透光開口１１４を除く面積の１％以上５０％以下が好ましく、２％以上４０％以下がより好ましい。これにより、キャリアを効率よく回収しつつ、半導体基板１１１の光電変換に寄与する面積を十分に確保できる。 The area of the surface electrode 120 in a plan view is preferably 1% or more and 50% or less, and more preferably 2% or more and 40% or less of the area of the semiconductor substrate 111 excluding the translucent opening 114. As a result, it is possible to secure a sufficient area that contributes to the photoelectric conversion of the semiconductor substrate 111 while efficiently recovering the carriers.
　裏面電極１３０は、第２半導体層１１３が引き寄せたキャリアを電荷として取り出す。裏面電極１３０は、表面電極１２０と同様の材料により形成できる。裏面電極１３０は、表面電極１２０と同様に、複数の透光開口１１４を個別に取り囲む複数の囲繞部を有する網状に形成されてもよいが、透光開口１１４を除いて光を透過させる必要がないので、光電変換体１１０の裏面全体に積層されてもよい。 The back surface electrode 130 takes out the carriers attracted by the second semiconductor layer 113 as electric charges. The back surface electrode 130 can be formed of the same material as the front surface electrode 120. Like the front surface electrode 120, the back surface electrode 130 may be formed in a mesh shape having a plurality of surrounding portions individually surrounding the plurality of translucent openings 114, but it is necessary to transmit light except for the translucent openings 114. Therefore, it may be laminated on the entire back surface of the photoelectric converter 110.
　以上のように、本実施形態に係る太陽電池セル１０１は、複数の透光開口１１４を有することで裏面に採光できるシースルー型の太陽電池セルである。加えて、太陽電池セル１０１は、表面電極１２０が透光開口１１４を個別に取り囲む複数の囲繞部１２１を有するため、キャリアの移動距離が大きい領域を有しないので、光電変換効率が高い。 As described above, the solar cell 101 according to the present embodiment is a see-through type solar cell that can collect light on the back surface by having a plurality of translucent openings 114. In addition, since the surface electrode 120 has a plurality of surrounding portions 121 individually surrounding the translucent opening 114, the solar cell 101 does not have a region where the carrier travel distance is large, so that the photoelectric conversion efficiency is high.
＜第３実施形態＞
　図１３は、本発明の第２実施形態に係る太陽電池セル１０１Ａの模式平面図である。なお、以降の実施形態について、先に説明した実施形態と同様の構成要素には同じ符号を付して重複する説明を省略することがある。 <Third Embodiment>
FIG. 13 is a schematic plan view of the solar cell 101A according to the second embodiment of the present invention. In the following embodiments, the same components as those in the above-described embodiment may be designated by the same reference numerals and duplicate description may be omitted.
　太陽電池セル１０１Ａは、表裏に貫通する複数の透光開口１１４を有する板状の光電変換体１１０と、光電変換体１１０の表面に積層される表面電極１２０Ａと、光電変換体１１０の裏面に積層される不図示の裏面電極と、を備える。 The solar cell 101A has a plate-shaped photoelectric converter 110 having a plurality of translucent openings 114 penetrating the front and back surfaces, a surface electrode 120A laminated on the surface of the photoelectric converter 110, and laminated on the back surface of the photoelectric converter 110. It is provided with a back surface electrode (not shown).
　表面電極１２０Ａは、複数の透光開口１１４を個別に取り囲む複数の正六角形状の囲繞部１２１Ａを有する。囲繞部１２１Ａは、各辺を隣接する囲繞部１２１Ａと共有する。このような構成とすることによって、特に透光開口１１４の面積率を大きくする場合にも、表面電極１２０Ａを適切に配置できる。 The surface electrode 120A has a plurality of regular hexagonal surrounding portions 121A that individually surround the plurality of translucent openings 114. The surrounding portion 121A shares each side with the adjacent surrounding portion 121A. With such a configuration, the surface electrode 120A can be appropriately arranged even when the area ratio of the translucent opening 114 is increased.
　表面電極１２０Ａは、複数の透光開口１１４を個別に取り囲む複数の正六角形状の囲繞部１２１Ａを有する。囲繞部１２１Ａは、各辺を隣接する囲繞部１２１Ａと共有する。このような構成とすることによって、特に透光開口１１４の面積率を大きくする場合にも、表面電極１２０Ａを適切に配置できる。 The surface electrode 120A has a plurality of regular hexagonal surrounding portions 121A that individually surround the plurality of translucent openings 114. The surrounding portion 121A shares each side with the adjacent surrounding portion 121A. With such a configuration, the surface electrode 120A can be appropriately arranged even when the area ratio of the translucent opening 114 is increased.
＜第４実施形態＞
　図１４は、本発明の第３実施形態に係る太陽電池セル１０１Ｂの模式平面図である。太陽電池セル１０１Ｂは、表裏に貫通する平面視で楕円形状の複数の透光開口１１４Ｂを有する板状の光電変換体１１０Ｂと、光電変換体１１０Ｂの表面に積層される表面電極１２０Ｂと、光電変換体１１０Ｂの裏面に積層される不図示の裏面電極と、を備える。 <Fourth Embodiment>
FIG. 14 is a schematic plan view of the solar cell 101B according to the third embodiment of the present invention. The solar cell 101B includes a plate-shaped photoelectric converter 110B having a plurality of elliptical transparent openings 114B in a plan view penetrating the front and back, a surface electrode 120B laminated on the surface of the photoelectric converter 110B, and a photoelectric conversion. A back surface electrode (not shown) laminated on the back surface of the body 110B is provided.
　表面電極１２０Ｂは、複数の透光開口１１４Ｂを個別に取り囲む複数の菱形状の囲繞部１２１Ｂを有する。囲繞部１２１Ｂは、各辺を隣接する囲繞部１２１Ｂと共有する。このように、平面視で楕円形状の透光開口１１４Ｂを取り囲む囲繞部１２１Ｂを菱形状に形成することによって、キャリアの最大移動距離を小さくできる。 The surface electrode 120B has a plurality of diamond-shaped surrounding portions 121B that individually surround the plurality of translucent openings 114B. The surrounding portion 121B shares each side with the adjacent surrounding portion 121B. In this way, the maximum moving distance of the carrier can be reduced by forming the surrounding portion 121B surrounding the elliptical transparent opening 114B in a plan view in a diamond shape.
＜第５実施形態＞
　図１５は、本発明の第４実施形態に係る太陽電池セル１０１Ｃの模式平面図である。太陽電池セル１０１Ｃは、表裏に貫通する平面視で三角形状の複数の透光開口１１４Ｃを有する板状の光電変換体１１０Ｃと、光電変換体１１０Ｃの表面に積層される表面電極１２０Ｃと、光電変換体１１０Ｃの裏面に積層される不図示の裏面電極と、を備える。 <Fifth Embodiment>
FIG. 15 is a schematic plan view of the solar cell 101C according to the fourth embodiment of the present invention. The solar cell 101C has a plate-shaped photoelectric converter 110C having a plurality of triangular translucent openings 114C in a plan view penetrating the front and back, a surface electrode 120C laminated on the surface of the photoelectric converter 110C, and a photoelectric conversion. A back surface electrode (not shown) laminated on the back surface of the body 110C is provided.
　表面電極１２０Ｂは、複数の透光開口１１４Ｃを個別に取り囲む複数の三角形状の囲繞部１２１Ｃを有する。複数の囲繞部１２１Ｃは各頂点で互いに接続され、複数の囲繞部１２１の間に透光開口１１４Ｃを含まない三角形状の残余スペースが画定される。 The surface electrode 120B has a plurality of triangular surrounding portions 121C that individually surround the plurality of translucent openings 114C. The plurality of surrounding portions 121C are connected to each other at each vertex, and a triangular residual space not including the translucent opening 114C is defined between the plurality of surrounding portions 121.
　以上、本発明の各実施形態について説明したが、本発明は上述した実施形態に限定されることなく、種々の変更及び変形が可能である。本発明に係る太陽電池セルは、例えば反射防止膜等、さらなる構成要素を備えてもよい。具体例として、第１電極と第１半導体層の間、及び第２電極と第２半導体層の間を接続するさらなる導電層等を設けてもよい。また、本発明に係る太陽電池セルにおいて、パッシベーション層は省略されてもよい。 Although each embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications and modifications can be made. The solar cell according to the present invention may include additional components such as an antireflection film. As a specific example, a further conductive layer or the like connecting between the first electrode and the first semiconductor layer and between the second electrode and the second semiconductor layer may be provided. Further, in the solar cell according to the present invention, the passivation layer may be omitted.
　本発明に係る太陽電池セルにおいて、透光開口の第１周面部と第２周面部とは、加工工程の違いに起因する表面性状の違いを有するだけであってもよい。このため、透光開口の内周面おいて、半導体基板は、全体的に露出してもよい。 In the solar cell according to the present invention, the first peripheral surface portion and the second peripheral surface portion of the translucent opening may only have a difference in surface texture due to a difference in the processing process. Therefore, the semiconductor substrate may be exposed as a whole on the inner peripheral surface of the translucent opening.
　また、本発明に係る太陽電池セルにおいて、少なくとも第１周面部の半導体基板はパッシベーション層のみで被覆されてもよい。この場合、パッシベーション層は、絶縁性を有するシリコン酸化膜、シリコン窒化膜等から形成されてもよい。 Further, in the solar cell according to the present invention, at least the semiconductor substrate on the first peripheral surface portion may be covered with only the passivation layer. In this case, the passivation layer may be formed of an insulating silicon oxide film, a silicon nitride film, or the like.
　上述の実施形態では、第１周面部が受光面側に位置するものとしたが、発明に係る太陽電池セルでは、第２周面部が受光面側に位置してもよい。 In the above-described embodiment, the first peripheral surface portion is located on the light receiving surface side, but in the solar cell according to the invention, the second peripheral surface portion may be located on the light receiving surface side.
　本発明に係る太陽電池セル製造方法において、第１半導体層及び第２半導体層を形成した後に環状溝を形成してもよい。この場合、第１半導体層の全面にレジスト材料を積層した状態でレーザ光を照射して環状溝を形成することで、同時にレジスト材料のパターニングを行うことができる。さらに、環状溝の形成後又は透光開口形成後にパッシベーション層を形成し、例えば導電性ペーストの印刷及び焼成によりパッシベーション層を貫通する電極を形成してもよい。 In the solar cell manufacturing method according to the present invention, the annular groove may be formed after the first semiconductor layer and the second semiconductor layer are formed. In this case, the resist material can be patterned at the same time by irradiating the laser beam with the resist material laminated on the entire surface of the first semiconductor layer to form the annular groove. Further, the passivation layer may be formed after the formation of the annular groove or the formation of the translucent opening, and an electrode penetrating the passivation layer may be formed by, for example, printing and firing of a conductive paste.
　また、複数の太陽電池セルを一列に並べて接続する場合、他の太陽電池セルに隣接する外縁に沿う電極線の幅を大きくすることにより、この電極線を他の電極線から電荷を集めて外部に出力するためのバスバーとして使用できるようにしてもよい。また、表面電極は、別途設けられるバスバーを有してもよく、１つの電極線群がバスバーに垂直に接続するよう配置され、この電極線群の電極線の太さが他の電極線より大きくてもよい。これにより、表面電極が光電変換体から電荷を収集した点からバスバーまでの電気抵抗を低減して、太陽電池セル全体の光電変換効率を向上できる。 In addition, when connecting multiple solar cells side by side in a row, by increasing the width of the electrode line along the outer edge adjacent to the other solar cell, this electrode line collects charge from other electrode lines and is external. It may be possible to use it as a bus bar for outputting to. Further, the surface electrode may have a bus bar provided separately, and one electrode wire group is arranged so as to be connected vertically to the bus bar, and the thickness of the electrode wire of this electrode wire group is larger than that of the other electrode wire. You may. As a result, the electrical resistance from the point where the surface electrode collects the electric charge from the photoelectric converter to the bus bar can be reduced, and the photoelectric conversion efficiency of the entire solar cell can be improved.
　１　太陽電池セル
　１０　半導体基板
　１１　透光開口
　１２　第１周面部
　１３　第２周面部
　２０　第１半導体層
　３０　第２半導体層
　４０　第１パッシベーション層
　５０　第２パッシベーション層
　６０　第１電極
　７０　第２電極
　１０１，１０１Ａ，１０１Ｂ，１０１Ｃ　太陽電池セル
　１１０，１１０Ｂ，１１０Ｃ　光電変換体
　１１１　半導体基板
　１１２　第１半導体層
　１１３　第２半導体層
　１１４，１４Ｂ　透光開口
　１２０，１２０Ａ，１２０Ｂ，１２０Ｃ　表面電極
　１２１，１２１Ａ，１２１Ｂ，１２０Ｃ　囲繞部
　１２２　電極線
　１２３，１２４，１２５　電極線群
　１３０　裏面電極
　Ｇ　環状溝 1 Solar cell 10 Semiconductor substrate 11 Translucent opening 12 1st peripheral surface 13 2nd peripheral surface 20 1st semiconductor layer 30 2nd semiconductor layer 40 1st passion layer 50 2nd passion layer 60 1st electrode 70 2nd electrode 101 , 101A, 101B, 101C Solar cell 110, 110B, 110C Photoconverter 111 Semiconductor substrate 112 First semiconductor layer 113 Second semiconductor layer 114, 14B Translucent opening 120, 120A, 120B, 120C Surface electrode 121, 121A, 121B , 120C Surrounding part 122 Electrode wire 123, 124, 125 Electrode wire group 130 Backside electrode G annular groove

Claims (13)

  1. 　板状に形成され、厚み方向に貫通する複数の透光開口を有する半導体基板と、
    　前記半導体基板の一方の主面側に積層される第１半導体層と、
    　前記半導体基板の他方の主面側に積層される第２半導体層と、
    　前記第１半導体層に積層される第１電極と、
    　前記第２半導体層に積層される第２電極と、
    を備え、
    　前記透光開口の内周面は、前記第１半導体層の側に位置する第１周面部と、前記第２半導体層の側に位置し、前記第１周面部と表面性状が異なる第２周面部と、を有する、太陽電池セル。     A semiconductor substrate formed in a plate shape and having a plurality of translucent openings penetrating in the thickness direction,
    A first semiconductor layer laminated on one main surface side of the semiconductor substrate,
    A second semiconductor layer laminated on the other main surface side of the semiconductor substrate, and
    The first electrode laminated on the first semiconductor layer and
    The second electrode laminated on the second semiconductor layer and
    Equipped with
    The inner peripheral surface of the translucent opening is located on the side of the first peripheral surface portion located on the side of the first semiconductor layer and on the side of the second semiconductor layer, and the surface texture is different from that of the first peripheral surface portion. A solar cell having a face portion and.
  2. 　前記第１周面部において、前記半導体基板は前記第１半導体層によって被覆され、
    　前記第２周面部において、前記半導体基板は露出する、請求項１に記載の太陽電池セル。     In the first peripheral surface portion, the semiconductor substrate is covered with the first semiconductor layer, and the semiconductor substrate is covered with the first semiconductor layer.
    The solar cell according to claim 1, wherein the semiconductor substrate is exposed on the second peripheral surface portion.
  3. 　半導体基板にレーザ光を照射することによって環状溝を形成する工程と、
    　前記環状溝の底部のエッチング又は割断により前記半導体基板の前記環状溝の内側の領域を分離することによって、前記半導体基板に開口を形成する工程と、
    を備える、太陽電池セル製造方法。     The process of forming an annular groove by irradiating a semiconductor substrate with laser light,
    A step of forming an opening in the semiconductor substrate by separating the inner region of the annular groove of the semiconductor substrate by etching or cutting the bottom of the annular groove.
    A solar cell manufacturing method.
  4. 　前記環状溝を形成する工程と前記開口を形成する工程との間に、前記半導体基板に成膜を行う工程をさらに備える、請求項３に記載の太陽電池セル製造方法。 The solar cell manufacturing method according to claim 3, further comprising a step of forming a film on the semiconductor substrate between the step of forming the annular groove and the step of forming the opening.
  5. 　半導体基板及び前記半導体基板に積層される半導体層を有し、且つ表裏に貫通する複数の透光開口を有する光電変換体と、
    　前記光電変換体の表面に積層される表面電極と、
    　前記光電変換体の裏面に積層される裏面電極と、
    を備え、
    　前記表面電極は、前記複数の透光開口を個別に取り囲む複数の囲繞部を有する、太陽電池セル。     A photoelectric converter having a semiconductor substrate and a semiconductor layer laminated on the semiconductor substrate, and having a plurality of translucent openings penetrating the front and back surfaces.
    A surface electrode laminated on the surface of the photoelectric converter and
    The back surface electrode laminated on the back surface of the photoelectric converter and
    Equipped with
    The surface electrode is a solar cell having a plurality of surrounding portions individually surrounding the plurality of translucent openings.
  6. 　前記囲繞部は多角形状である、請求項５に記載の太陽電池セル。 The solar cell according to claim 5, wherein the surrounding portion has a polygonal shape.
  7. 　前記囲繞部の各辺の長さは一定である、請求項６に記載の太陽電池セル。 The solar cell according to claim 6, wherein the length of each side of the surrounding portion is constant.
  8. 　前記囲繞部の各辺と前記透光開口との距離の最小値は最大値の５０％以上である、請求項６又は７に記載の太陽電池セル。 The solar cell according to claim 6 or 7, wherein the minimum value of the distance between each side of the surrounding portion and the translucent opening is 50% or more of the maximum value.
  9. 　前記囲繞部の各辺と前記透光開口との距離は前記透光開口の直径の２０％以上１５０％以下である、請求項６から８のいずれかに記載の太陽電池セル。 The solar cell according to any one of claims 6 to 8, wherein the distance between each side of the surrounding portion and the translucent opening is 20% or more and 150% or less of the diameter of the translucent opening.
  10. 　前記表面電極は、それぞれ平行且つ等間隔に配置される複数の電極線からなり、互いに交差するよう角度が異なる３組の電極線群を有する、請求項５から９のいずれかに記載の太陽電池セル。 The solar cell according to any one of claims 5 to 9, wherein the surface electrodes are composed of a plurality of electrode wires arranged in parallel and at equal intervals, and have three sets of electrode wire groups having different angles so as to intersect each other. cell.
  11. 　前記囲繞部は、頂点で互いに接する六角形状であり、間に前記透光開口を含まない三角形状のスペースを画定する、請求項９に記載の太陽電池セル。 The solar cell according to claim 9, wherein the surrounding portions have a hexagonal shape that is in contact with each other at the apex, and a triangular space that does not include the translucent opening is defined between them.
  12. 　前記複数の囲繞部の内側の面積は、前記複数の囲繞部の外側の面積の２倍以上５倍以下である、請求項５から１１のいずれかに記載の太陽電池セル。 The solar cell according to any one of claims 5 to 11, wherein the area inside the plurality of surrounding parts is twice or more and five times or less the area outside the plurality of surrounding parts.
  13. 　前記裏面電極は、前記複数の透光開口を個別に取り囲む複数の囲繞部を有する、請求項５から１２のいずれかに記載の太陽電池セル。 The solar cell according to any one of claims 5 to 12, wherein the back surface electrode has a plurality of surrounding portions individually surrounding the plurality of translucent openings.
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