Layer, photoelectric conversion module, method for forming layer, and method for manufacturing photoelectric conversion module

Abstract

Provided is a method for forming a layer, wherein a film can be formed inside a groove with a high precision. This method for forming a layer includes: a groove forming step for forming a groove (P2) along a first direction (Y direction) in a base layer (40); and a film forming step for forming a layer on the base layer (40) by physical vapor deposition or chemical vapor deposition while moving the base layer (40) in the first direction.

Description

LAYER, PHOTOELECTRIC CONVERSION MODULE, LAYER FORMING METHOD, AND PHOTOELECTRIC CONVERSION MODULE MANUFACTURING METHOD - Patent application

[0001] The present invention relates to a layer, a photoelectric conversion module, a method for forming a layer, and a method for manufacturing a photoelectric conversion module.

[0002] A photoelectric conversion module that converts light energy into electrical energy is known (see Patent Document 1). The photoelectric conversion module described in Patent Document 1 includes a plurality of photoelectric conversion elements arranged adjacent to each other. Each photoelectric conversion element has a conductive substrate, a first electrode layer on the conductive substrate, a photoelectric conversion layer on the first electrode layer, and a second electrode layer on the photoelectric conversion layer.

[0003] A marginal groove is formed between the first electrode layers of adjacent photoelectric conversion elements. A groove is formed between the photoelectric conversion layers of adjacent photoelectric conversion elements. The second electrode layer of the photoelectric conversion element is also provided in a part of the groove formed between the photoelectric conversion layers of adjacent photoelectric conversion elements, and is electrically connected to the first electrode layer of the adjacent photoelectric conversion element.

[0004] Japanese Patent Application Laid-Open No. 2021-174868

[0005] The second electrode layer (layer) is also formed in the groove formed between the adjacent photoelectric conversion layers to electrically connect the first electrode layer of a photoelectric conversion element with the second electrode layer of the adjacent photoelectric conversion element. However, it may be difficult to form the layer inside the groove, especially when the groove width is narrow.

[0006] Therefore, there is a demand for a layer that is formed accurately inside a groove, a photoelectric conversion element having such a layer, a method for forming a layer that can be formed accurately inside a groove, and a method for manufacturing a photoelectric conversion module.

[0007] A layer formation method according to one embodiment includes a groove formation step of forming a groove along a first direction in an underlayer, and a film formation step of forming a layer on the underlayer by physical vapor deposition or chemical vapor deposition while moving the underlayer in the first direction.

[0008] A method for manufacturing a photovoltaic module according to one aspect includes a first conductive layer forming step of forming a first conductive layer, a step of forming the base layer by depositing a photovoltaic layer on the first conductive layer, and a second conductive layer forming step of forming a second conductive layer on the base layer. The second conductive layer forming step is formed by the above-described layer forming method.

[0009] The layer according to one embodiment is a layer formed by the above-described method for forming a layer.

[0010] A photoelectric conversion module according to one embodiment is a photoelectric conversion element manufactured by the above-described method for manufacturing a photoelectric conversion module.

[0011] FIG. 1 is a schematic perspective view of a photovoltaic conversion module according to the first embodiment. FIG. 2 is a schematic top view of the photovoltaic conversion module as viewed from the direction of arrow 2A in FIG. 1 . FIG. 3 is a schematic side view of the photovoltaic conversion module as viewed from the direction of arrow 3A in FIG. 1 . FIG. 4 is a schematic enlarged view of a first conductive layer as viewed from the direction of arrow 4A in FIG. 1 . FIG. 5 is a schematic enlarged view of a second conductive layer as viewed from the direction of arrow 4A in FIG. 1 . FIG. 6 is a diagram for explaining the flow of a method for manufacturing a photovoltaic conversion module according to the first embodiment. FIG. 7 is a schematic view for explaining one step of the method for manufacturing a photovoltaic conversion module according to the first embodiment. FIG. 8 is a schematic view for explaining a film formation step in a first conductive layer formation step. FIG. 9 is a schematic enlarged view of region 9R in FIG. 8 . FIG. 10 is a diagram showing a micrograph of the conductive layer after the film formation step. FIG. 11 is a schematic view for explaining a groove formation step (first groove formation step) in the first conductive layer formation step. FIG. 12 is a schematic diagram illustrating a state subsequent to FIG. 11 . FIG. 13 is a schematic diagram illustrating a state subsequent to FIG. 12 . FIG. 14 is a schematic cross-sectional view taken along line 14A-14A in FIG. 11 . FIG. 15 is a schematic side view illustrating a state after the photoelectric conversion layer and the buffer layer have been formed. FIG. 16 is a schematic diagram illustrating a step of forming grooves in the photoelectric conversion layer and the buffer layer (second groove formation step). FIG. 17 is a schematic cross-sectional view taken along line 17A-17A in FIG. 16 . FIG. 18 is a schematic diagram illustrating a film formation step in the second conductive layer formation step. FIG. 19 is a schematic cross-sectional view taken along line 19A-19A in FIG. 18 . FIG. 20 is a schematic side view illustrating a state subsequent to the film formation step in the second conductive layer formation step. FIG. 21 is a schematic diagram illustrating a groove formation step (third groove formation step) in the second conductive layer formation step. FIG. 22 is a schematic diagram illustrating a state subsequent to FIG. 21 . Fig. 23 is a schematic view for explaining a state subsequent to Fig. 22. Fig. 24 is a schematic view for explaining a state in which a film is formed while moving the substrate in a direction (second direction) intersecting the longitudinal direction of the groove in a film forming step in the second conductive layer forming process.

[0012] Hereinafter, embodiments will be described with reference to the drawings. In the following drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and the ratios of the dimensions may differ from those of the actual parts.

[0013] [Photoelectric conversion module] Fig. 1 is a schematic perspective view of a photoelectric conversion module according to a first embodiment. Fig. 2 is a schematic top view of the photoelectric conversion module as seen from the direction of arrow 2A in Fig. 1. Fig. 3 is a schematic side view of the photoelectric conversion module as seen from the direction of arrow 3A in Fig. 1. It should be noted that Figs. 1 to 3 show only a portion of the photoelectric conversion module.

[0014] The photoelectric conversion module 10 according to this embodiment may be, for example, an integrated thin-film photoelectric conversion module. The photoelectric conversion module 10 may include a substrate 20 and a plurality of photoelectric conversion elements (cells) 12. The plurality of photoelectric conversion elements 12 may be integrated on the substrate 20. Preferably, the photoelectric conversion module 10 is a solar cell module that converts light energy into electrical energy.

[0015] The substrate 20 may be a base on which each film is formed, and may be made of, for example, glass, ceramics, resin, or metal.

[0016] Each photoelectric conversion element 12 may have a substantially strip-like shape when viewed from a direction perpendicular to the main surface of the substrate 20. Each photoelectric conversion element 12 may extend elongatedly in a first direction (Y direction in the figure; the same applies below). Furthermore, the multiple photoelectric conversion elements 12 are arranged in a second direction (X direction in the figure; the same applies below) that intersects with the first direction. Adjacent photoelectric conversion elements 12 may be electrically and / or structurally separated from each other by a first groove P1, a second groove P2, and a third groove P3 that extend in the first direction.

[0017] In this specification, the term "groove" includes both a groove with a bottom and a groove without a bottom, and also includes a state in which the groove is filled with a material other than the material (layer) in which the groove is formed.

[0018] Each photoelectric conversion element 12 may include at least a first electrode layer 22, a photoelectric conversion layer 26 on the first electrode layer 22, and a second electrode layer 24 on the photoelectric conversion layer 26. The photoelectric conversion layer 26 is provided between the first electrode layer 22 and the second electrode layer 24. The first electrode layer 22 is provided on a substrate 20. The second electrode layer 24 is located on the opposite side of the photoelectric conversion layer 26 from the substrate 20.

[0019] The first electrode layer (conductive layer) 22 may be made of a conductive metal material or oxide material. The metal material can be at least one selected from Ag, Al, Au, Cu, Mo, Ni, Pt, Ti, and Cr, or an alloy thereof. The conductive oxide material can be selected from, for example, ITO (indium tin oxide), ITiO (indium titanium oxide), IZO (indium zinc oxide), ZTO (zinc tin oxide), FTO (fluorine-doped tin oxide), GZO (gallium-doped zinc oxide), etc.

[0020] The second electrode layer (conductive layer) 24 may be made of a conductive metal material or oxide material. The metal material can be at least one selected from Ag, Al, Au, Cu, Mo, Ni, Pt, Ti, and Cr, or an alloy thereof. The conductive oxide material can be selected from, for example, ITO (indium tin oxide), ITiO (indium titanium oxide), IZO (indium zinc oxide), ZTO (zinc tin oxide), FTO (fluorine-doped tin oxide), GZO (gallium-doped zinc oxide), etc.

[0021] In one example, the second electrode layer 24 may be composed of a transparent electrode layer. In this case, the first electrode layer 22 may be a transparent electrode layer or an opaque electrode layer. When the second electrode layer 24 is composed of a transparent electrode layer, light incident on or emitted from the photoelectric conversion layer 26 may pass through the second electrode layer 24.

[0022] In another example, the first electrode layer 22 may be composed of a transparent electrode layer. In this case, the substrate 20 is a transparent substrate such as a glass substrate, and the second electrode layer 24 may be a transparent electrode layer or an opaque electrode layer. When the first electrode layer 22 is composed of a transparent electrode layer, light incident on or emitted from the photoelectric conversion layer 26 may pass through the substrate 20 and the first electrode layer 22.

[0023] In a preferred example, the second electrode layer 24 is formed of an n-type semiconductor, more specifically, a material having n-type conductivity, a wide band gap, and relatively low resistance. The second electrode layer 24 may be formed of, for example, zinc oxide (ZnO) doped with a Group III element or indium tin oxide (ITO). In this case, the second electrode layer 24 can function as both an n-type semiconductor and a transparent electrode layer.

[0024] The photoelectric conversion layer 26 may include, for example, a p-type semiconductor. In one example of a CIS-based photoelectric conversion module, the photoelectric conversion layer 26 is formed of a compound semiconductor including a Group I element (Cu, Ag, Au, etc.), a Group III element (Al, Ga, In, etc.), and a Group VI element (O, S, Se, Te, etc.). Alternatively, the photoelectric conversion layer 26 is not limited to the above-mentioned materials and may be made of any material that causes photoelectric conversion.

[0025] It should be noted that the configuration of the photoelectric conversion element 12 is not limited to the above embodiment and can take various forms. For example, the photoelectric conversion element 12 may have a configuration in which both an n-type semiconductor and a p-type semiconductor are sandwiched between a first electrode layer and a second electrode layer. In this case, the second electrode layer does not need to be composed of an n-type semiconductor. Furthermore, the photoelectric conversion element 12 is not limited to a p-n junction type structure, and may have a p-i-n junction type structure that includes an intrinsic semiconductor layer (i-type semiconductor) between an n-type semiconductor and a p-type semiconductor.

[0026] The photoelectric conversion element 12 may have a buffer layer 25 between the photoelectric conversion layer 26 and the second electrode layer 24. In this case, the buffer layer 25 may be a semiconductor material having the same conductivity type as the second electrode layer 24, or may be a semiconductor material having a different conductivity type. The buffer layer 25 may be made of a material having a higher electrical resistance than the second electrode layer 24. In an example of a CIS-based photoelectric conversion module, the buffer layer 25 may be a Zn-based buffer layer, a Cd-based buffer layer, or an In-based buffer layer.

[0027] The first electrode layers 22 of adjacent photoelectric conversion elements 12 are electrically separated from each other by a first groove P1. Similarly, the second electrode layers 24 of adjacent photoelectric conversion elements 12 are electrically separated from each other by a third groove P3. The photoelectric conversion layers 26 of adjacent photoelectric conversion elements 12 are separated from each other by a second groove P2 and a third groove P3. The first groove P1, the second groove P2, and the third groove P3 extend along the first direction.

[0028] The width of the first groove P1 in the second direction may be, for example, in the range of 30 to 200 μm, preferably in the range of 30 to 100 μm, and more preferably in the range of 30 to 60 μm. The width of the second groove P2 in the second direction may be, for example, in the range of 30 to 200 μm, preferably in the range of 30 to 100 μm, and more preferably in the range of 30 to 60 μm. The width of the third groove P3 in the second direction may be, for example, in the range of 30 to 200 μm, preferably in the range of 30 to 100 μm, and more preferably in the range of 30 to 60 μm.

[0029] The photoelectric conversion module 10 may have electrical connection portions 34 between adjacent photoelectric conversion elements 12. The electrical connection portions 34 electrically connect the adjacent photoelectric conversion elements 12 in series. In this embodiment, the electrical connection portions 34 are formed by portions that extend continuously from the second electrode layer 24. In this case, the electrical connection portions 34 are made of the same material as the material that constitutes the second electrode layer 24.

[0030] The electrical connection portion 34 extends in the thickness direction of the photoelectric conversion module 10 at the second groove P2, thereby electrically connecting the first electrode layer 22 of one photoelectric conversion element 12 to the second electrode layer 24 of the other photoelectric conversion element 12.

[0031] Fig. 4 is a schematic enlarged view of the first conductive layer as viewed from the direction of arrow 4A in Fig. 1. Fig. 4 schematically shows the shape of columnar crystals constituting the first electrode layer (first conductive layer) 22. In this embodiment, the plurality of columnar crystals constituting the first electrode layer 22 have the shape of a substantially rectangular parallelepiped or substantially ellipsoid that extends long in one direction.

[0032] The major axis directions of the plurality of columnar crystals constituting the first electrode layer 22 are oriented at an angle from the direction perpendicular to the surface of the first electrode layer 22. Specifically, the plurality of columnar crystals constituting the first electrode layer 22 are oriented at an angle from the direction perpendicular to the surface of the first electrode layer 22 (thickness direction) toward a first direction along the surface of the first electrode layer 22. In other words, the plurality of columnar crystals constituting the first electrode layer 22 are oriented at an angle from the direction perpendicular to the surface of the first electrode layer 22 (thickness direction) toward the longitudinal direction of the first groove P1.

[0033] Fig. 5 is a schematic enlarged view of the second conductive layer as viewed from the direction of arrow 4A in Fig. 1. Fig. 5 schematically shows the shape of the columnar crystals constituting the second electrode layer (second conductive layer) 24. In this embodiment, the plurality of columnar crystals constituting the second electrode layer 24 have the shape of a substantially rectangular parallelepiped or substantially ellipsoid that extends long in one direction.

[0034] The major axis directions of the plurality of columnar crystals constituting the second electrode layer 24 are oriented at an angle from the direction perpendicular to the surface of the second electrode layer 24. Specifically, the plurality of columnar crystals constituting the second electrode layer 24 are oriented at an angle from the direction perpendicular to the surface of the second electrode layer 24 (thickness direction) to a first direction along the surface of the second electrode layer 24. In other words, the plurality of columnar crystals constituting the second electrode layer 24 are oriented at an angle from the direction perpendicular to the surface of the second electrode layer 24 (thickness direction) toward the longitudinal direction of the third groove P3.

[0035] In this embodiment, the major axis directions of the plurality of columnar crystals constituting the first electrode layer 22 and the second electrode layer 24 are oriented at an angle from the thickness direction toward the longitudinal directions of the first grooves P1 and the third grooves P3, respectively. Alternatively, the major axis directions of the columnar crystals of at least one of the first conductive layer 22 and the second conductive layer 24 may be oriented at an angle toward the longitudinal direction of the first grooves P1 or the third grooves P3.

[0036] If necessary, the photovoltaic conversion module 10 may have wiring (not shown) for extracting power from the photovoltaic conversion module 10. The photovoltaic conversion module 10 may also have a sealing material (not shown) for sealing the first electrode layer 22, the photovoltaic conversion layer 26, the buffer layer 25, and the second electrode layer 24.

[0037] [Layer Forming Method and Photovoltaic Conversion Module Manufacturing Method] Next, a layer forming method will be described. A method for manufacturing the photovoltaic conversion module will be described below with reference to FIGS. 6 to 23 , and the layer forming method will also be described in the description.

[0038] 6 is a diagram illustrating the flow of the method for manufacturing the photovoltaic conversion module according to the first embodiment. The method for manufacturing the photovoltaic conversion module may include a first conductive layer forming step S1, a photovoltaic layer forming step S2, a buffer layer forming step S3, and a second conductive layer forming step S4.

[0039] (First conductive layer forming step S1) FIG. 7 is a schematic view illustrating one step of the manufacturing method for the photovoltaic conversion module according to the first embodiment. FIG. 8 is a schematic view illustrating a film forming step in the first conductive layer forming step. FIG. 9 is a schematic enlarged view of region 9R in FIG. 8. FIG. 10 is a diagram illustrating a microscope photograph of the conductive layer after the film forming step. FIG. 11 is a schematic view illustrating a groove forming step (first groove forming step) in the first conductive layer forming step. FIG. 12 is a schematic view illustrating a state subsequent to FIG. 11. FIG. 13 is a schematic view illustrating a state subsequent to FIG. 12. FIG. 14 is a schematic cross-sectional view taken along line 14A-14A in FIG. 11.

[0040] The first conductive layer forming step S1 may include a film forming step S1a followed by a first groove forming step S1b. In the first conductive layer forming step S1, a first electrode layer (first conductive layer) 22 is formed on the substrate 20.

[0041] First, in the film-forming step S1a, a first electrode layer (first conductive layer) 22 is formed on the substrate 20 while the substrate 20 is being moved in a first direction. The movement of the substrate 20 in the first direction can be achieved, for example, by moving a stage on which the substrate 20 is placed. The first electrode layers 22 of the multiple photoelectric conversion elements 12 are formed on the substrate 20 in a batch.

[0042] By forming a film while moving the substrate 20, the substrate 20 can be moved to the next manufacturing unit while the film is being formed, which has the advantage of enabling mass production of photovoltaic conversion modules.

[0043] The material constituting the first electrode layer 22 preferably includes a metal material or an oxide material. The metal material can be at least one selected from Ag, Al, Au, Cu, Mo, Ni, Pt, Ti, and Cr, or an alloy thereof. The conductive oxide material can be selected from, for example, ITO (indium tin oxide), ITiO (indium titanium oxide), IZO (indium zinc oxide), ZTO (zinc tin oxide), FTO (fluorine-doped tin oxide), GZO (gallium-doped zinc oxide), etc.

[0044] The first electrode layer 22 can be formed by a physical vapor deposition (PVD) method, a chemical vapor deposition (CVD) method, or the like. The physical vapor deposition method can be selected from a sputtering method, a vacuum deposition method, an ion plating method, or the like. The sputtering method can be a direct current (DC) sputtering method or a radio frequency (RF) sputtering method. The chemical vapor deposition method can be selected from a thermal CVD method, a plasma CVD method, an atomic layer deposition (ALD) method, a metal organic chemical vapor deposition (MOCVD) method, or the like.

[0045] The moving speed of the substrate 20 in the first direction may be, for example, in the range of 2 to 60 mm / s, preferably in the range of 30 to 60 mm / s, and more preferably in the range of 45 to 60 mm / s.

[0046] In the film formation step, during physical vapor deposition or chemical vapor deposition, particles 22s constituting a metal material or oxide material rain down onto the moving substrate 20 (see FIG. 8 ). Therefore, the particles 22s heading toward the surface of the substrate 20 rain down in a direction (oblique direction) tilted from a direction perpendicular to the surface of the substrate 20 toward the first direction. As a result, it is considered that the plurality of columnar crystals 22a formed on the substrate 20 are oriented with a tilt from a direction (thickness direction) perpendicular to the surface of the first electrode layer 22 toward the first direction along the surface of the first electrode layer 22, as described above (see also FIGS. 9 and 10 ).

[0047] 10 shows a micrograph of the first electrode layer 22 after the film formation step, showing that a plurality of columnar crystals 22a of the first electrode layer 22 formed on the substrate 20 are oriented with an inclination from the thickness direction to the first direction. In FIG. 10, the moving speed of the substrate 20 in the film formation step was low, so the inclination of the columnar crystals 22a is small. It is believed that if the film is formed while moving the substrate 20 at a faster speed, the inclination of the columnar crystals 22a will become greater.

[0048] Next, in the first groove formation step S1b, first grooves P1 are formed along the first direction in the first electrode layer 22 formed in the film formation step S1a (FIGS. 11 to 14). That is, the first grooves P1 extend along the direction of movement of the substrate 20 in the film formation step S1a. The first grooves P1 divide the first electrode layer 22 formed in the film formation step S1a into a plurality of regions corresponding to the respective photoelectric conversion elements 12.

[0049] The first groove P1 is preferably formed by a laser or a mechanical blade. In the first groove forming step S1b, the substrate 20 may be moved in the first direction while the laser irradiation position or the mechanical blade position SP is kept stationary. Alternatively, the laser irradiation position or the mechanical blade position SP may be moved in the first direction while the substrate 20 is kept stationary.

[0050] Furthermore, as shown in Figures 11 to 13, in order to form each of the multiple first grooves P1 of the photoelectric conversion module 10 in sequence, the multiple first grooves P1 may be formed in sequence while the laser irradiation position or the mechanical blade position SP and the substrate 20 are moved back and forth relative to each other along the first direction.

[0051] In the first groove forming step S1b, the first grooves P1 are preferably formed so that the width of the first grooves P1 is, for example, in the range of 30 to 200 μm, preferably in the range of 30 to 100 μm, and more preferably in the range of 30 to 60 μm.

[0052] In this embodiment, as described above, the multiple columnar crystals 22a constituting the first electrode layer 22 are considered to be oriented with an inclination from the thickness direction toward the first direction (see also FIGS. 9 and 10 ). In other words, the columnar crystal boundaries 22b are inclined toward the first direction on the side surface viewed from the second direction. If the first groove P1 were formed along the second direction in this state, the columnar crystal boundaries 22b at both ends of the first groove P1 in the first direction would be inclined toward the first direction, which would likely result in processing defects at both ends of the first groove P1 and make it difficult to form both ends of the first groove P1 neatly and straight. On the other hand, in this embodiment, the first groove P1 is formed along the first direction. In this case, the columnar crystal boundaries 22b at both ends of the first groove P1 in the second direction are barely inclined toward the second direction, which would prevent processing defects at both ends of the first groove P1 and make it easier to form both ends of the first groove P1 neatly and straight. As described above, according to this embodiment, the first groove P1 can be formed with high processing quality.

[0053] (Step S2 of forming photoelectric conversion layer) Next, the photoelectric conversion layer 26 is formed on the first electrode layer 22 with the first groove P1 formed in. In one example of a CIS-based photoelectric conversion module, the photoelectric conversion layer 26 is formed by forming a thin-film precursor layer and then chalcogenizing the precursor layer.

[0054] Examples of methods for forming a precursor layer on the first electrode layer 22 include sputtering, vapor deposition, and ink coating. Vapor deposition is a method for forming a film using atoms or the like that are vaporized by heating a vapor deposition source. Ink coating is a method for forming a precursor film by dispersing a powder of precursor film material in a solvent such as an organic solvent and applying it to the first electrode layer 22, and then evaporating the solvent to form a precursor layer.

[0055] The precursor layer includes a Group I element and a Group III element. For example, the precursor layer may include Ag as the Group I element. The Group I element other than Ag contained in the precursor layer may be selected from copper, gold, etc. The Group III element contained in the precursor layer may be selected from indium, gallium, aluminum, etc. The precursor layer may also include an alkali metal such as Li, Na, K, Rb, or Cs. The precursor layer may also include tellurium as a Group VI element in addition to selenium and sulfur.

[0056] In the chalcogenization treatment of the precursor layer, the precursor layer is chalcogenized by heat treatment in an atmosphere containing a Group VI element to form the photoelectric conversion layer 26. For example, selenization is first performed by vapor-phase selenization, in which the precursor layer is heated in an atmosphere of a selenium source gas (e.g., hydrogen selenide or selenium vapor) containing selenium as a Group VI element source.

[0057] As a result, the precursor layer is converted into a compound (photoelectric conversion layer 26) containing a group I element, a group III element, and selenium. Note that the compound (photoelectric conversion layer 26) containing a group I element, a group III element, and selenium may be formed by a method other than vapor-phase selenization. For example, such a compound can also be formed by solid-phase selenization, vapor deposition, ink application, electrodeposition, or the like.

[0058] Next, the photoelectric conversion layer 26 containing a group I element, a group III element, and selenium is sulfurized. The sulfurization is performed by heating the photoelectric conversion layer 26 in an atmosphere of a sulfur-containing sulfur source gas (e.g., hydrogen sulfide or sulfur vapor). As a result, the photoelectric conversion layer 26 is converted into a compound containing a group I element, a group III element, and selenium and sulfur as group VI elements. The sulfur source gas serves to substitute sulfur for selenium in crystals composed of a group I element, a group III element, and selenium, for example, chalcopyrite crystals, on the surface portion of the photoelectric conversion layer 26.

[0059] An example of a CIS-based photoelectric conversion module has been described as the deposition of the photoelectric conversion layer 26. Alternatively, a photoelectric conversion layer 26 having a different layer structure may be deposited. In this case, the deposition of the photoelectric conversion layer 26 may be selected appropriately depending on the layer structure.

[0060] (Step S3 of forming a buffer layer) Next, if necessary, the buffer layer 25 is formed on the photoelectric conversion layer 26. The buffer layer 25 can be formed by a method such as a CBD (Chemical Bath Deposition) method or a sputtering method. The material constituting the buffer layer 25 is as described above. Note that the formation of the buffer layer 25 may be omitted.

[0061] Fig. 15 is a schematic side view for explaining the state after the photoelectric conversion layer and buffer layer are formed. By forming the photoelectric conversion layer 26 and the buffer layer 25, a structure (underlying layer) as shown in Fig. 15 is obtained. Here, Fig. 15 shows the state as seen from the direction corresponding to the arrow 3A in Fig. 1, i.e., the same direction as Fig. 3.

[0062] (Second Conductive Layer Forming Step S4) FIG. 16 is a schematic diagram for explaining a step of forming grooves in the photoelectric conversion layer and the buffer layer (second groove forming step). FIG. 17 is a schematic cross-sectional view taken along line 17A-17A in FIG. 16. FIG. 18 is a schematic cross-sectional view taken along line 19A-19A in FIG. 18. FIG. 20 is a schematic side view for explaining a state after the film forming step in the second conductive layer forming step. FIG. 21 is a schematic diagram for explaining a groove forming step (third groove forming step) in the second conductive layer forming step. FIG. 22 is a schematic diagram for explaining a state subsequent to FIG. 21. FIG. 23 is a schematic diagram for explaining a state subsequent to FIG. 22.

[0063] Next, a second conductive layer forming step S4 is performed. The second conductive layer forming step S4 may include a second groove forming step S4a, a film forming step S4b, and a third groove forming step S4c.

[0064] In the second groove forming step S4a, second grooves P2 are formed along the first direction in a stack including the substrate 20, the first electrode layer 22, the photoelectric conversion layer 26, and the buffer layer 25 (see FIG. 16 ). Hereinafter, the stack including the substrate 20, the first electrode layer 22, the photoelectric conversion layer 26, and the buffer layer 25, and the stack including the substrate 20, the first electrode layer 22, and the photoelectric conversion layer 26 may be referred to as the "underlayer" (the same applies hereinafter). However, the underlayer is not limited to the stack having the above configuration, and may have any configuration as long as it is a layer that serves as a base for forming the second electrode layer (second conductive layer) 24. The underlayer is indicated by the reference numeral 40 in the figure.

[0065] Specifically, in the second groove forming step S4a, second grooves P2 are formed along the first direction in the photoelectric conversion layer 26 and the buffer layer 25. The second grooves P2 preferably reach the surface of the first electrode layer 22 in the thickness direction. The second grooves P2 divide the photoelectric conversion layer 26 and the buffer layer 25 into a plurality of regions corresponding to the respective photoelectric conversion elements 12.

[0066] The second grooves P2 are preferably formed by a laser or a mechanical blade. In the second groove forming step S4a, the base layer 40 may be moved in the first direction while the laser irradiation position or the mechanical blade position SP is kept stationary. Alternatively, the laser irradiation position or the mechanical blade position SP may be moved in the first direction while the base layer 40 is kept stationary.

[0067] In order to prevent the second grooves P2 from being formed in the first electrode layer 22, the second grooves P2 are preferably formed by a mechanical blade.

[0068] In the second groove forming step S4a, the second grooves P2 are preferably formed so that the width of the second grooves P2 is, for example, in the range of 30 to 200 μm, preferably in the range of 30 to 100 μm, and more preferably in the range of 30 to 60 μm.

[0069] As shown in Figure 16, in order to form each of the multiple second grooves P2 of the photoelectric conversion module 10 in sequence, the multiple second grooves P2 may be formed in sequence while the laser irradiation position or the mechanical blade position SP and the base layer 40 are moved back and forth relative to each other along the first direction.

[0070] Next, in a film-forming step S4b, a second electrode layer 24 (second conductive layer) is formed on the base layer 40. In the film-forming step S4b, the second electrode layer (second conductive layer) 24 is formed on the base layer 40 while the base layer 40 is being moved in a first direction. The movement of the base layer 40 in the first direction can be achieved, for example, by moving a stage on which the base layer 40, specifically the substrate 20, is placed. The second electrode layers 24 of the multiple photoelectric conversion elements 12 are formed collectively on the base layer 40.

[0071] By depositing the base layer 40 while moving it, the substrate 20 can be moved to the next manufacturing unit while the film is being deposited, which has the advantage of enabling mass production of photovoltaic conversion modules.

[0072] The material constituting the second electrode layer 24 preferably includes a metal material or an oxide material. The metal material can be at least one selected from Ag, Al, Au, Cu, Mo, Ni, Pt, Ti, and Cr, or an alloy thereof. The conductive oxide material can be selected from, for example, ITO (indium tin oxide), ITiO (indium titanium oxide), IZO (indium zinc oxide), ZTO (zinc tin oxide), FTO (fluorine-doped tin oxide), GZO (gallium-doped zinc oxide), etc.

[0073] The second electrode layer 24 can be formed by a PVD method, a CVD method, or the like. The PVD method can be selected from a sputtering method, a vacuum deposition method, an ion plating method, or the like. The sputtering method can be a DC sputtering method or an RF sputtering method. The CVD method can be selected from a thermal CVD method, a plasma CVD method, an ALD method, an MOCVD method, or the like.

[0074] In the film-forming step S4b, during physical vapor deposition or chemical vapor deposition, particles 24s constituting the metal material or oxide material rain down onto the moving underlayer 40. Therefore, the particles 24s heading toward the surface of the underlayer 40 rain down in a direction (oblique direction) tilted from a direction perpendicular to the surface of the underlayer 40 toward the first direction. As a result, it is considered that the plurality of columnar crystals 24a formed on the underlayer 40 are oriented with a tilt from a direction (thickness direction) perpendicular to the surface of the second electrode layer 24 toward the first direction along the surface of the second electrode layer 24, as described above (see also FIG. 5 ).

[0075] Here, instead of the above embodiment, consider performing physical vapor deposition or chemical vapor deposition while moving the base layer 40, i.e., the substrate 20, in a second direction. Figure 24 is a schematic diagram illustrating film formation while moving the substrate in a direction (second direction) intersecting the longitudinal direction of the second grooves P2 in the film formation step S4b of the second conductive layer formation process S4. During physical vapor deposition or chemical vapor deposition, particles 24s constituting the metal material or oxide material rain down in a direction (oblique direction) inclined from a direction perpendicular to the surface of the base layer 40 toward the second direction. However, the region SD of the second grooves P2 shown in Figure 24 is shielded by the photoelectric conversion layer 26 and buffer layer 25 adjacent to the second grooves P2, so particles constituting the metal material or oxide material are less likely to adhere to the region SD.

[0076] On the other hand, when physical vapor deposition or chemical vapor deposition is performed while moving the underlayer 40, i.e., the substrate 20, in the longitudinal direction (first direction) of the second groove P2, as in the above-described embodiment, the particles 24s falling in an oblique direction tend to reach the entire area inside the second groove P2, as shown in FIGS. 18 and 19 . Therefore, the second electrode layer (second conductive layer) 24 is more reliably formed inside the second groove P2. This more reliably forms the aforementioned electrical connection portion 34 (see also FIG. 20 ). This reduces the possibility of poor electrical connection between the second electrode layer 24 of a given photoelectric conversion element 12 and the first electrode layer 22 of an adjacent photoelectric conversion element 12.

[0077] The moving speed of the underlayer 40 in the first direction may be, for example, in the range of 2 to 60 mm / s, preferably in the range of 30 to 60 mm / s, and more preferably in the range of 45 to 60 mm / s.

[0078] Next, in the third groove forming step S4c, third grooves P3 are formed along the first direction in the second electrode layer 24 formed in the film forming step S4b (FIGS. 21 to 23). That is, the third grooves P3 extend along the direction of movement of the substrate 20 in the film forming step S4b. The third grooves P3 divide the second electrode layer 24 formed in the film forming step S4b into a plurality of regions corresponding to the respective photoelectric conversion elements 12.

[0079] The third groove P3 is preferably formed by a laser or a mechanical blade. In the third groove forming step S4c, the substrate 20 may be moved in the first direction while the laser irradiation position or the mechanical blade position SP is kept stationary. Alternatively, the laser irradiation position or the mechanical blade position SP may be moved in the first direction while the substrate 20 is kept stationary.

[0080] Furthermore, as shown in Figures 21 to 23, in order to form each of the multiple third grooves P3 of the photoelectric conversion module 10 in sequence, the multiple third grooves P3 may be formed in sequence while the laser irradiation position or the mechanical blade position SP and the substrate 20 are moved back and forth relative to each other along the first direction.

[0081] In the third groove forming step S4c, the third grooves P3 are preferably formed so that the width of the third grooves P3 is in the range of, for example, 30 to 200 μm, preferably 30 to 100 μm, and more preferably 30 to 60 μm.

[0082] In this embodiment, the plurality of columnar crystals 24a and the columnar crystal boundaries 24b constituting the second electrode layer 24 are considered to be oriented at an angle from the thickness direction to the first direction, similar to the plurality of columnar crystals 24a and the columnar crystal boundaries 24b constituting the first electrode layer 22 (see also FIG. 5 ). When the third groove P3 is formed along the first direction in this state, it is easy to form both end portions of the third groove P3 neatly and straight, as described for the first electrode layer 22 in the first conductive layer forming step S1. Thus, according to this embodiment, the third groove P3 can be formed with high processing quality.

[0083] Next, if necessary, wiring may be connected to extract power from the photovoltaic conversion module 10. Furthermore, a sealing material (not shown) may be formed to seal the first electrode layer 22, the photovoltaic conversion layer 26, the buffer layer 25, and the second electrode layer 24.

[0084] In the above embodiment, the present invention has been disclosed using a photovoltaic conversion module and a method for manufacturing the photovoltaic conversion module as examples. However, it should be noted that the second conductive layer formation step S4, more specifically the combination of the second groove formation step S4a and the film formation step S4b, can be applied to any layer formation method. That is, a layer formation method according to one aspect may include a groove formation step of forming a groove along a first direction in an underlayer, and a film formation step of forming a layer on the underlayer by sputtering or vapor deposition while moving the underlayer in the first direction. Here, the underlayer material, groove formation conditions, layer material, and layer formation conditions described in the above embodiment can be used. The layer formed on the underlayer is not particularly limited, but may be a conductive layer. In this case, the conductive layer may correspond to either or both of the first conductive layer 22 and the second conductive layer 24 described in the above embodiment.

[0085] As described above, the contents of the present invention have been disclosed through the embodiments, but the descriptions and drawings that form part of this disclosure should not be understood to limit the present invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure. Therefore, the technical scope of the present invention is defined only by the inventive features of the claims that can be reasonably understood from the above description.

[0086] This application claims priority based on Japanese Patent Application No. 2023-190254, filed on November 7, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. A method for forming a layer, comprising: a groove forming step for forming a groove along a first direction in an underlayer; and a film forming step for forming a layer on the underlayer by physical vapor deposition or chemical vapor deposition while moving the underlayer in the first direction.

2. The method of claim 1, wherein the grooves are formed by a laser or a mechanical blade.

3. The method for forming a layer according to claim 1 or 2, wherein the material forming the layer includes a metal material or an oxide material.

4. A method for forming a layer according to any one of claims 1 to 3, wherein the moving speed of the substrate in the first direction is in the range of 2 to 60 mm / s.

5. A method for forming a layer according to any one of claims 1 to 4, wherein the moving speed of the substrate in the first direction is in the range of 30 to 60 mm / s.

6. A method for forming a layer according to any one of claims 1 to 5, wherein the moving speed of the substrate in the first direction is in the range of 45 to 60 mm / s.

7. The method for forming a layer according to any one of claims 1 to 6, wherein in the groove forming step, the groove is formed so that the width of the groove is in the range of 30 to 200 μm.

8. The method for forming a layer according to any one of claims 1 to 7, wherein in the groove forming step, the groove is formed so that the width of the groove is in the range of 30 to 100 μm.

9. The method for forming a layer according to any one of claims 1 to 8, wherein in the groove forming step, the groove is formed so that the width of the groove is in the range of 30 to 60 μm.

10. The method for forming a layer according to any one of claims 1 to 9, wherein the layer comprises a layer containing inclined columnar crystals.

11. The method for forming a layer according to any one of claims 1 to 10, wherein the layer is a layer that constitutes a photoelectric conversion element.

12. The method for forming a layer according to any one of claims 1 to 11, wherein the layer comprises a conductive layer.

13. A method for manufacturing a photoelectric conversion module, comprising: a first conductive layer formation step of forming a first conductive layer; a step of depositing a photoelectric conversion layer on the first conductive layer to form the base layer; and a second conductive layer formation step of forming a second conductive layer on the base layer, wherein the second conductive layer formation step is formed by a layer formation method described in any one of claims 1 to 12.

14. A layer formed by the method for forming a layer according to any one of claims 1 to 12.

15. A photoelectric conversion element manufactured by the method for manufacturing a photoelectric conversion module according to claim 13.