JP2012049190A - Method of manufacturing substrate for photoelectric conversion device and method of manufacturing photoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method of manufacturing a substrate for a photoelectric conversion device, which is capable of realizing a photoelectric conversion device which has high photoelectric conversion efficiency because of an excellent light trapping effect, and to obtain a method of manufacturing the photoelectric conversion device.SOLUTION: The method of manufacturing a substrate for a photoelectric conversion device includes: a first step of depositing a conductive material film on a substrate 11 to form an electrode layer 21; a second step of etching the electrode layer 21 formed on the substrate 11, by using an alkaline etching solution, to form a plurality of first recesses 71 having a depth dimension larger than an opening diameter dimension on a surface of the electrode layer 21; and a third step of etching the electrode layer 21 having the first recesses 71 formed thereon, by using an acidic etching solution, to form second recesses on the surface of the electrode layer 21 by greatly enlarging opening diameters of the first recesses 71.

Description

  The present invention relates to a method for manufacturing a substrate for a photoelectric conversion device and a method for manufacturing a photoelectric conversion device, and more particularly to a method for manufacturing a substrate for a photoelectric conversion device having a light confinement structure and a method for manufacturing a photoelectric conversion device.

  In recent years, development of a thin-film silicon photoelectric conversion device using amorphous silicon, microcrystalline silicon, or the like has been actively performed. There are two particularly important things in the development of these photoelectric conversion devices. One is cost reduction and the other is high performance. The thin film silicon photoelectric conversion device is characterized in that the photoelectric conversion layer is thinner than the crystalline silicon photoelectric conversion device in which a bulk body such as a single crystal or polycrystal is used.

  That is, the thickness of the photoelectric conversion layer of the crystalline silicon-based photoelectric conversion device is several hundred μm, whereas the thickness of the photoelectric conversion layer of the thin-film silicon-based photoelectric conversion device is several μm. Thereby, the thin film silicon-based photoelectric conversion device has an advantage that the silicon raw material necessary for forming the device can be reduced as compared with the crystalline silicon-based photoelectric conversion device. On the other hand, in the thin film silicon-based photoelectric conversion device, the utilization efficiency of incident light is lower than that of the crystalline silicon-based photoelectric conversion device. For this reason, in the thin-film silicon-based photoelectric conversion device, the utilization efficiency of incident light is increased by using an optical confinement technique.

  In general, light confinement technology is a method of forming an uneven shape called a texture structure on the light incident side or reflection side electrode layer of a photoelectric conversion device, and reflecting the incident light or reflected light by this uneven shape, thereby reducing the optical path length. This is a technology that stretches the light and reflects light multiple times in the photoelectric conversion layer. As one of the methods for forming the uneven shape, there is a method of forming a surface texture structure by etching the electrode layer after forming the electrode layer (see, for example, Patent Document 1 and Patent Document 2).

  Patent Document 1 forms a surface texture structure by forming a transparent conductive layer as an electrode layer and etching the surface of the transparent conductive layer at least twice using an etching solution comprising an acidic solution or an alkaline solution. Is described. Further, in Patent Document 2, in a thin film solar cell including at least a transparent electrode layer and a photoelectric conversion layer, a surface texture structure is formed by etching the surface of the transparent conductive layer using an etching solution containing at least one alcohol derivative. Is described.

  In Patent Document 1, for example, when forming an uneven shape by performing wet etching twice on a transparent electrode layer using zinc oxide (ZnO) as a material, the etching solution used for the second etching is the first time. It is described that the concentration is reduced with respect to an etching solution used for etching. As a result, finer irregularities are produced in the second etching than the irregularities produced in the first etching.

JP 2004-119491 A Japanese Patent No. 4248793

  However, in this method, when the fine irregularities are produced by the second etching, the irregularities are rounded and become gentle. In general, infrared light has a lower light absorption coefficient than visible light. For this reason, efficient absorption of infrared light is indispensable to efficiently absorb the entire wavelength region of ultraviolet light to infrared light. However, in the method of Patent Document 1, although the light confinement effect in the ultraviolet to visible light region is increased by producing fine irregularities, the light confinement effect in the visible light to infrared light region is decreased. Therefore, there is a problem that the characteristics of the final photoelectric conversion device are deteriorated.

  Furthermore, in order to scatter infrared light, an uneven shape having an uneven diameter of not less than the wavelength of infrared light, that is, 1 μm or more is required. However, the method of Patent Document 1 has a problem that the film forming conditions of the transparent electrode layer are limited in order to produce an uneven shape having an uneven diameter of 1 μm or more.

  Patent Document 2 describes the use of an etchant containing an alcohol derivative. In general, alcohol derivatives are more expensive than acid / alkali aqueous solutions such as hydrochloric acid and sodium hydroxide. For this reason, the method of Patent Document 2 has a problem that it lacks mass productivity because the cost of the etching process increases.

  The present invention has been made in view of the above, and provides a method for manufacturing a substrate for a photoelectric conversion device and a photoelectric conversion device capable of realizing a photoelectric conversion device having a good light confinement effect and having high photoelectric conversion efficiency. It aims at obtaining a manufacturing method.

  In order to solve the above-described problems and achieve the object, a method for manufacturing a substrate for a photoelectric conversion device according to the present invention is provided for a photoelectric conversion device including an electrode layer made of a conductive material and having an uneven shape on the surface. A method for manufacturing a substrate, comprising: forming a conductive material film on the substrate to form the electrode layer; and etching the electrode layer formed on the substrate using an alkaline etching solution. Performing a second step of forming a plurality of first recesses having a depth dimension larger than the opening diameter dimension with respect to the surface of the electrode layer, and acidity with respect to the electrode layer having the first recesses formed therein. And a third step of forming a second recess on the surface of the electrode layer by enlarging the opening diameter of the first recess by etching using an etching solution.

  According to the present invention, it is possible to obtain a favorable light confinement effect and to obtain a photoelectric conversion device having high photoelectric conversion efficiency.

FIG. 1 is a diagram illustrating a schematic configuration of a silicon-based thin film photoelectric conversion device which is a photoelectric conversion device according to a first embodiment of the present invention. FIG. 2-1 is a cross-sectional view schematically showing the method for manufacturing the silicon-based thin film photoelectric conversion device according to the first embodiment. 2-2 is sectional drawing which shows typically the manufacturing method of the silicon type thin film photoelectric conversion apparatus concerning Embodiment 1. FIGS. FIG. 3 is a flowchart for explaining the method for manufacturing the silicon-based thin film photoelectric conversion device according to the first embodiment. FIG. 4 is a diagram illustrating a schematic configuration of a silicon-based thin film photoelectric conversion device which is a photoelectric conversion device according to the second embodiment of the present invention. 5-1 is sectional drawing which shows typically the manufacturing method of the silicon type thin film photoelectric conversion apparatus concerning Embodiment 2. FIGS. 5-2 is sectional drawing which shows typically the manufacturing method of the silicon type thin film photoelectric conversion apparatus concerning Embodiment 2. FIGS. FIG. 6 is a cross-sectional view schematically showing how the light incident side transparent electrode layer according to Comparative Example 1 is etched. FIG. 7 is a cross-sectional view schematically showing how the light incident side transparent electrode layer according to Comparative Example 2 is etched. FIG. 8 is a scanning electron micrograph showing the surface state of the light incident side transparent electrode layer according to the example after the etching process. FIG. 9 is a scanning electron micrograph showing the surface state of the light incident side transparent electrode layer according to Comparative Example 1 and Comparative Example 2 after the etching treatment. FIG. 10 is a characteristic diagram illustrating the haze ratio of the light incident side transparent electrode layer of the photoelectric conversion device substrate according to the example. FIG. 11 is a characteristic diagram showing the haze ratio of the light incident side transparent electrode layer of the substrate for a photoelectric conversion device according to Comparative Example 1. FIG. 12 is a characteristic diagram showing the haze ratio of the light incident side transparent electrode layer of the photoelectric conversion device substrate according to Comparative Example 2. FIG. 13 is a characteristic diagram showing the quantum efficiency of the silicon-based thin film photoelectric conversion devices according to the example, the comparative example 1, and the comparative example 2.

  EMBODIMENT OF THE INVENTION Below, embodiment of the manufacturing method of the board | substrate for photoelectric conversion apparatuses concerning this invention and the manufacturing method of a photoelectric conversion apparatus is described in detail based on drawing. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. In the drawings shown below, the scale of each member may be different from the actual scale for easy understanding. The same applies between the drawings.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a schematic configuration of a silicon-based thin film photoelectric conversion device which is a photoelectric conversion device according to a first embodiment of the present invention. The silicon-based thin film photoelectric conversion device according to the first embodiment is formed on the substrate 11 on the light incident side transparent electrode layer 21, the thin film silicon-based photoelectric conversion unit 3, the light reflecting side transparent electrode layer 41, and the back surface side. The light reflection side metal electrode layer 51 is sequentially laminated. With respect to this silicon-based thin film photoelectric conversion device, the light L to be subjected to photoelectric conversion is incident from the substrate 11 side.

  The substrate 11 is located on the light incident side and needs to have a light-transmitting property in order to transmit light, and a substrate such as glass, an organic film, or ceramics can be used. A light incident side transparent electrode layer 21 is formed on the substrate 11. For this reason, it is preferable that melting | fusing point of the board | substrate 11 is higher than the film forming temperature of these transparent conductive films.

  The light incident side transparent electrode layer 21 is made of a light-transmitting conductive material, and is preferably made of, for example, zinc oxide (ZnO). In addition, for the purpose of reducing resistivity, aluminum doped zinc oxide (AZO) and gallium doped zinc oxide (GZO) in which a doping material such as aluminum (Al) and gallium (Ga) is mixed with zinc oxide (ZnO) are used. Also good. Alternatively, zinc oxide doped with indium and gallium (In—Ga—ZnO), zinc oxide doped with indium (In—ZnO), or a transparent conductive film (ITO) may be used. The light incident side transparent electrode layer 21 is formed on the substrate 11 by a known method such as vacuum deposition, CVD (Chemical Vapor Deposition), or sputtering.

  In addition, a concavo-convex shape called a texture structure is formed on the light incident side surface of the light incident side transparent electrode layer 21, that is, the joint surface with the thin film silicon-based photoelectric conversion unit 3. By having this texture structure, a good light confinement effect can be obtained.

  The film thickness of the light incident side transparent electrode layer 21 formed on the substrate 11 is preferably, for example, 100 nm to 10 μm, and more preferably 1 μm to 10 μm. When the film thickness of the light incident side transparent electrode layer 21 is less than 100 nm, the light confinement effect by the uneven structure of the light incident side transparent electrode layer 21 becomes insufficient. When the light incident side transparent electrode layer 21 is thicker than 10 μm, the difference in film stress between the light incident side transparent electrode layer 21 and the substrate 11 is increased, and the light incident side transparent electrode layer 21 is peeled off, Or a fine crack will enter into the light incident side transparent electrode layer 21.

  The thin film silicon-based photoelectric conversion unit 3 is formed on the light incident side transparent electrode layer 21 by, for example, CVD, and p-type hydrogenated microcrystalline silicon (μc-Si: H) in order from the light incident side transparent electrode layer 21 side. ) Layer, i-type hydrogenated microcrystalline silicon (μc-Si: H) layer, and n-type hydrogenated microcrystalline silicon (μc-Si: H) layer. The thin-film silicon-based photoelectric conversion unit 3 includes a p-type hydrogenated amorphous silicon carbide (a-SiC: H) layer and an i-type hydrogenated amorphous silicon (a-Si: a) in order from the light incident side transparent electrode layer 21 side. H) layer, n-type hydrogenated amorphous silicon (a-Si: H) layer, p-type hydrogenated microcrystalline silicon (μc-Si: H) layer, i-type hydrogenated microcrystalline silicon (μc-Si: A pin junction structure having a two-layer tandem structure including an H) layer and an n-type hydrogenated microcrystalline silicon (μc-Si: H) layer may be used. Furthermore, the thin-film silicon-based photoelectric conversion unit 3 includes a p-type hydrogenated amorphous silicon carbide (a-SiC: H) layer and an i-type hydrogenated amorphous silicon (a-Si: a) in order from the light incident side transparent electrode layer 21 side. H) layer, n-type hydrogenated amorphous silicon (a-Si: H) layer, p-type hydrogenated amorphous silicon germanium (a-SiGe: H), i-type hydrogenated amorphous silicon germanium (a-SiGe: H) ), N-type hydrogenated amorphous silicon germanium (a-SiGe: H), p-type hydrogenated microcrystalline silicon (μc-Si: H) layer, i-type hydrogenated microcrystalline silicon (μc-Si: H) Alternatively, a pin junction structure having a three-layer tandem structure including an n-type hydrogenated microcrystalline silicon (μc-Si: H) layer may be used. In addition, when a plurality of pin junctions are provided, μc-SiOx (x = 0 to 2) or ZnO is inserted between the pin junctions to improve electrical and optical connections between the pin junctions. Also good. Moreover, you may use a transparent conductive film (ITO) etc. instead of zinc oxide (ZnO).

The light reflection side transparent electrode layer 41 is formed immediately above the thin film silicon photoelectric conversion unit 3 and electrically connects the thin film silicon photoelectric conversion unit 3 and the light reflection side metal electrode layer 51. As a material of the light reflection side transparent electrode layer 41, zinc oxide (ZnO) tin oxide (SnO ₂ ) and a transparent conductive film (ITO) are preferable. Such a light reflection side transparent electrode layer 41 is formed by a known method such as a CVD method, a vapor deposition method or a sputtering method.

  The thin film silicon photoelectric conversion unit 3 efficiently absorbs light in the ultraviolet light or visible light region. On the other hand, the light absorptance in the near-infrared light region of the thin-film silicon-based photoelectric conversion unit 3 is lower than that in the ultraviolet light or visible light region. For this reason, the light in the near-infrared light region that has not been absorbed by the thin film silicon-based photoelectric conversion unit 3 passes through the light reflection side transparent electrode layer 41 and is reflected by the light reflection side metal electrode layer 51, and further the light reflection side It passes through the transparent electrode layer 41 and enters the thin film silicon photoelectric conversion unit 3 again. For this reason, as the light transmittance in the visible light or near infrared light region in the light reflection side transparent electrode layer 41 increases, the characteristics of the photoelectric conversion device, in particular, the current value increases.

  The light reflection side metal electrode layer 51 has a role of extracting light that has passed through the thin film silicon photoelectric conversion unit 3 in addition to a role of taking out the photoelectrically converted current. Examples of the material of the light reflection side metal electrode layer 51 include silver (Ag), titanium (Ti), aluminum (Al), and molybdenum (Mo). Among these, silver (Ag) is particularly preferable from the viewpoint of electrical characteristics and light reflection characteristics. Such a light reflection side metal electrode layer 51 is formed by a known method, but a vapor deposition method or a sputtering method is preferable.

  Next, a method for manufacturing the silicon-based thin film photoelectric conversion device according to the first embodiment will be described with reference to FIGS. 2-1, 2-2 and FIG. 2A and 2B are cross-sectional views schematically showing the method for manufacturing the silicon-based thin film photoelectric conversion device according to the first embodiment. FIG. 3 is a flowchart for explaining the method for manufacturing the silicon-based thin film photoelectric conversion device according to the first embodiment. First, the manufacturing method of the substrate for photoelectric conversion devices which has the light-incidence side transparent electrode layer 21 on the board | substrate 11 is demonstrated. First, a light incident side transparent electrode layer 21 made of, for example, zinc oxide (ZnO) is formed on a substrate 11 made of glass, an organic film, ceramics, or the like by a known method such as vacuum deposition, CVD, or sputtering (FIG. 2). -1 (a), step S110).

  After the light incident side transparent electrode layer 21 is formed, the first etching process is performed (FIG. 2-1 (b), step S120). In the first etching step, an uneven shape is formed on the surface of the light incident side transparent electrode layer 21 by etching using an alkaline solution to form the surface uneven structure 61. Among the concave and convex portions formed by this etching, the depth to the bottom is deeper than many other concave portions, and the aspect ratio of the depth to the bottom with respect to the opening diameter on the surface side is extremely large. Large depressions are sparsely present. As will be described later, in a later step, etching is performed so as to widen the opening diameter of the deep recess. Therefore, hereinafter, this deep recess is referred to as an etching starting point 71.

  As the alkaline solution used for etching in the first etching step, for example, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, calcium hydroxide aqueous solution, barium hydroxide aqueous solution and the like are preferable.

  Moreover, the light incident side transparent electrode layer 21 may be annealed before and after etching with an alkaline solution. By performing the annealing, the crystal grain size and crystal orientation of the light incident side transparent electrode layer 21 can be changed, and the etching rate can be adjusted. Further, examples of the etching method include an immersion method and a spray method using a shower nozzle, but are not limited thereto.

  When etching is performed using an alkaline solution, the opening diameter of the formed recess tends to be small, unlike when etching is performed using an acidic solution. Therefore, the opening diameter of the recess in the surface uneven structure 61 is preferably 50 nm to 500 nm, and the depth to the bottom of the recess at this time is preferably 100 nm to 1 μm. Moreover, it is preferable that the depth dimension of the recessed part which is the etching starting point 71 becomes a dimension 1.1 to 10 times the opening diameter of this recessed part. When the depth dimension of the recess that is the etching starting point 71 is smaller than 1.1 times the dimension of the opening diameter of the recess, in the second etching step, the dimension of the opening diameter of the recess is the depth of the recess. It is difficult to have an opening diameter of 1 μm or more because it is less than 1 time the size. Further, when the depth dimension of the concave portion as the etching starting point 71 is larger than 10 times the opening diameter of the concave portion, the etching starting point 71 of the light incident side transparent electrode layer 21 is determined in the second etching step. When the photoelectric conversion device is formed, power is not generated in the portion where the light incident side transparent electrode layer 21 is not formed and the characteristics of the photoelectric conversion device are deteriorated. Therefore, by setting the depth dimension of the concave portion, which is the etching starting point 71, to 1.1 to 10 times the opening diameter dimension of the concave portion, the dimension of the concave opening diameter is 1 μm or more with good reproducibility in the second etching step. It becomes.

The density and shape of the etching starting point 71 depend on the film forming conditions and the etching conditions of the light incident side transparent electrode layer 21. The light incident side transparent electrode layer 21 is preferably formed under film forming conditions such that the etching starting point 71 is a film formed at a rate of 1 × 10 ³ to 1 × 10 ⁶ within 1 mm ² . . When the etching starting point 71 is less than 1 × 10 ³ in 1 mm ² , unevenness having an opening diameter of 1 μm or more is not sufficiently formed in the second etching step, and the light scattering effect of near infrared light is sufficient. I can't get it. When the etching starting points 71 are more than 1 × 10 ⁶ in 1 mm ² , the distance between the etching starting points 71 is 1 μm or less, and an opening diameter of 1 μm or more cannot be obtained in the second etching step. For example, the light incident side transparent electrode layer 21 may be a zinc oxide film (ZnO), a zinc oxide film doped with indium and gallium (In—Ga—ZnO), a zinc oxide film doped with indium (In—ZnO), or a transparent conductive film. In the case of (ITO), the etching starting point 71 is formed under the above conditions by adjusting at least one of the deposition temperature condition of the zinc oxide film and the addition amount condition of the impurity doped into the zinc oxide film. A simple film can be formed.

  After the surface concavo-convex structure 61 and the etching starting point 71 are formed on the surface of the light incident side transparent electrode layer 21 by etching with an alkaline solution, a second etching process is performed (FIG. 2-1 (c), step S130). In the second etching step, the opening diameter of the concave portion of the surface concavo-convex structure 61 is increased around the etching starting point 71 by etching using an acidic solution. As the acidic solution used for etching in the second etching step, for example, an aqueous hydrochloric acid solution, an aqueous nitric acid solution, an aqueous sulfuric acid solution, an aqueous acetic acid solution, and the like are preferable.

  When etching is performed using an acidic solution, unlike the case where etching is performed using an alkaline solution, the opening diameter of the formed recess tends to be large. For this reason, the opening diameter of the concave portion of the final surface uneven structure 62 is preferably, for example, 100 nm to 10 μm, and more preferably 1 μm to 10 μm. In this case, the depth to the bottom of the recess is preferably 100 nm to 1 μm. Further, it is more preferable that the depth dimension of the recess is 0.1 to 1 times the dimension of the opening diameter of the recess. When the depth dimension of the recess is larger than one time the opening diameter of the recess, it is difficult to obtain an opening diameter of 1 μm or more. Further, when the depth dimension of the recess is smaller than 0.1 times the opening diameter of the recess, it is difficult to obtain a sufficient light scattering effect, but etching is further performed using an acidic solution. Thereby, the depth dimension of a recessed part can be 0.1 to 1 time the opening diameter of a recessed part. Therefore, by setting the depth dimension of the recess to 0.1 to 1 times the opening diameter of the recess, an opening diameter of 1 μm or more can be obtained, and the light scattering effect of near infrared light is increased.

  Further, the light incident side transparent electrode layer 21 may be annealed before and after the etching with the acidic solution. By performing the annealing, the crystal grain size and crystal orientation of the light incident side transparent electrode layer 21 can be changed, and the etching rate can be adjusted. For example, in the case of the light incident side transparent electrode layer 21 using zinc oxide as a material and formed at a substrate temperature of 200 ° C. using a sputtering method, the etching rate is as long as annealing is not performed before etching with an acidic solution. 20 nm / second. On the other hand, if the light incident side transparent electrode layer 21 is annealed at 400 degrees for 1 hour before etching with the acidic solution, the etching rate is reduced to 10 nm / second or less. Also, annealing of the light incident side transparent electrode layer 21 is performed after etching with an acidic solution, thereby improving the crystallinity of the light incident side transparent electrode layer 21 and increasing the light transmittance from visible light to near infrared light. be able to.

  As described above, in the first embodiment, in the first etching step, a deep recess (etching origin 71) is formed in the vertical direction on the film surface of the light incident side transparent electrode layer 21 using an alkaline etching solution. Then, in the second etching step, the film surface of the light incident side transparent electrode layer 21 is etched using an acidic etching solution, so that the opening diameter of the deep recess (etching starting point 71) is greatly widened. By performing such a process, the substrate for a photoelectric conversion device on which the light incident side transparent electrode layer 21 having a good light confinement effect is formed can be formed by a simple process. And since the recessed part whose opening diameter is 1 micrometer or more can be formed by said process, especially the board | substrate for photoelectric conversion apparatuses which can scatter the light of visible light-infrared light region favorably is formed by simple process. Can do.

  Next, a manufacturing method of the silicon-based thin film photoelectric conversion device according to the first embodiment using the substrate for the photoelectric conversion device will be described. First, the thin-film silicon-based photoelectric conversion unit 3 is formed on the light incident side transparent electrode layer 21 of the photoelectric conversion device substrate by, for example, a CVD method (FIG. 2-1 (d), step S140). As the thin film silicon-based photoelectric conversion unit 3, for example, a p-type hydrogenated microcrystalline silicon (μc-Si: H) layer, an i-type hydrogenated microcrystalline silicon (μc-Si) in this order from the light incident side transparent electrode layer 21 side. : H) layer and n-type hydrogenated microcrystalline silicon (μc-Si: H) layer are sequentially stacked. The surface shape of the thin-film silicon-based photoelectric conversion unit 3 is a shape that reflects the uneven shape that is the surface shape of the light incident side transparent electrode layer 21.

  Next, the light reflection side transparent electrode layer 41 is formed on the thin film silicon photoelectric conversion unit 3 by a known method (FIG. 2-2 (e), step S150). For example, the light reflection side transparent electrode layer 41 made of a zinc oxide (ZnO) film is formed on the thin film silicon photoelectric conversion unit 3 by a sputtering method. Further, as a film formation method, another film formation method such as a CVD method may be used.

  Subsequently, the light reflection side metal electrode layer 51 is formed on the light reflection side transparent electrode layer 41 by a known method (FIG. 2-2 (f), step S160). For example, the light reflection side metal electrode layer 51 made of a silver (Ag) film having a high reflectance is formed on the light reflection side transparent electrode layer 41 by a sputtering method. With the above processing, the silicon-based thin film photoelectric conversion device according to the first embodiment shown in FIG. 1 is obtained.

  As described above, in the first embodiment, first, a deep recess (etching start point 71) is formed in the vertical direction on the film surface of the light incident side transparent electrode layer 21 using an alkaline etching solution. Then, the film surface of the light incident side transparent electrode layer 21 is etched using an acidic etching solution to greatly widen the opening diameter of the deep recess (etching starting point 71). By performing such a process, a substrate for a photoelectric conversion device on which the light incident side transparent electrode layer 21 having a texture structure having a good light confinement effect is formed can be formed at a low cost by a simple process. . And since the recessed part whose opening diameter is 1 micrometer or more can be formed by said process, especially the board | substrate for photoelectric conversion apparatuses which can scatter the light of visible light-infrared light region favorably is formed by simple process. Can do.

  And since a silicon-based thin film photoelectric conversion device is produced using this substrate for a photoelectric conversion device, light in the visible light to infrared light region can be scattered well, and a good light confinement effect can be obtained in all wavelength regions. Thus, a photoelectric conversion device having high photoelectric conversion efficiency can be obtained.

Embodiment 2. FIG.
FIG. 4 is a diagram illustrating a schematic configuration of a silicon-based thin film photoelectric conversion device which is a photoelectric conversion device according to the second embodiment of the present invention. The silicon-based thin film photoelectric conversion device according to the second embodiment includes a light reflecting side transparent electrode layer 42A, a light reflecting side metal electrode layer 52, a light reflecting side transparent electrode layer 42B, and a thin film silicon based photoelectric device on a substrate 12. The conversion unit 3, the light incident side transparent electrode layer 22, and the grid electrode 84 are sequentially stacked. Unlike the case of the first embodiment, photoelectric conversion light L is incident on the silicon-based thin film photoelectric conversion device from the light incident side transparent electrode layer 22 side. In addition, about the same member as the silicon type thin film photoelectric conversion apparatus concerning Embodiment 1, detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol as FIG.

  Since the substrate 12 is located on the light reflection side, it is not particularly necessary to have transparency, and a metal material such as stainless steel can be used in addition to glass, an organic film, ceramics, and the like. A light reflection side transparent electrode layer 42 </ b> A is formed on the substrate 12. For this reason, it is preferable that the melting point of the substrate 12 is higher than the film forming temperature of the transparent conductive film of the light reflecting side transparent electrode layer 42A.

  The light reflection side transparent electrode layer 42A is made of a light-transmitting conductive material, and is preferably made of, for example, zinc oxide (ZnO). In addition, for the purpose of reducing resistivity, aluminum doped zinc oxide (AZO) and gallium doped zinc oxide (GZO) in which a doping material such as aluminum (Al) and gallium (Ga) is mixed with zinc oxide (ZnO) are used. Also good. Alternatively, zinc oxide doped with indium and gallium (In—Ga—ZnO), zinc oxide doped with indium (In—ZnO), or a transparent conductive film (ITO) may be used. The light reflecting side transparent electrode layer 42A is formed on the substrate 12 by a known method such as a vacuum deposition method, a CVD method, or a sputtering method.

  In addition, a concavo-convex shape called a texture structure is formed on the light incident side surface of the light reflecting side transparent electrode layer 42 </ b> A, that is, the joint surface with the light reflecting side metal electrode layer 52. By having this texture structure, a good light confinement effect can be obtained.

  The film thickness of the light reflection side transparent electrode layer 42A formed on the substrate 12 is preferably, for example, 100 nm to 10 μm, and more preferably 1 μm to 10 μm. When the film thickness of the light reflection side transparent electrode layer 42A is thinner than 100 nm, the light confinement effect by the surface uneven structure of the light reflection side transparent electrode layer 42A becomes insufficient. Further, when the film thickness of the light reflection side transparent electrode layer 42A is thicker than 10 μm, the difference in film stress between the light reflection side transparent electrode layer 42A and the substrate 12 increases, and the light reflection side transparent electrode layer 42A peels off, Or a fine crack will enter into the light reflection side transparent electrode layer 42A.

  The light reflection side metal electrode layer 52 has the same role as the light reflection side metal electrode layer 51 in the first embodiment. That is, the light reflection side metal electrode layer 52 has a role of reflecting light that has passed through the thin film silicon photoelectric conversion unit 3 in addition to the role of taking out the photoelectrically converted current. Examples of the material of the light reflection side metal electrode layer 52 include silver (Ag), titanium (Ti), aluminum (Al), molybdenum (Mo) and the like, similar to the light reflection side metal electrode layer 51. Among these, silver (Ag) is particularly preferable from the viewpoint of electrical characteristics and light reflection characteristics. Such a light reflection side metal electrode layer 52 is formed by a known method, but a vapor deposition method or a sputtering method is preferable.

The light reflection side transparent electrode layer 42B has the same role as the light reflection side transparent electrode layer 41 in the first embodiment. That is, the light reflection side transparent electrode layer 42 </ b> B is formed immediately below the thin film silicon photoelectric conversion unit 3, and electrically connects the thin film silicon photoelectric conversion unit 3 and the light reflection side metal electrode layer 52. As a material of the light reflection side transparent electrode layer 42B, ZnO, SnO ₂ and ITO are preferable. Such a light reflection side transparent electrode layer 42B is formed by a known method such as a CVD method, a vapor deposition method or a sputtering method.

The light incident side transparent electrode layer 22 is formed immediately above the thin film silicon photoelectric conversion unit 3 and electrically connects the thin film silicon photoelectric conversion unit 3 and the grid electrode 84. As a material of the light incident side transparent electrode layer 22, tin oxide (SnO ₂ ) and a transparent conductive film (ITO) are preferable. In the light incident side transparent electrode layer 22, the incident light passes before entering the thin film silicon-based photoelectric conversion unit 3. For this reason, the higher the light transmittance in the visible light or near-infrared light region, the more the characteristics of the photoelectric conversion device, particularly the current value.

  The grid electrode 84 has a role of taking out a photoelectrically converted current. Examples of the material of the grid electrode 84 include silver (Ag), titanium (Ti), aluminum (Al), and molybdenum (Mo). The grid electrode 84 is provided mainly for taking out current and does not need to have light reflectivity. For this reason, the material of the grid electrode 84 is preferably aluminum (Al) or a laminated structure of titanium (Ti) and aluminum (Al) in consideration of ohmic properties.

  Next, a method for manufacturing the silicon-based thin film photoelectric conversion device according to the second embodiment will be described with reference to FIGS. 5A and 5B are cross-sectional views schematically illustrating a method for manufacturing the silicon-based thin film photoelectric conversion device according to the second embodiment. First, a method for manufacturing a photoelectric conversion device substrate having the light reflection side transparent electrode layer 42A on the substrate 12 will be described. First, a light reflection side transparent electrode layer 42A made of, for example, zinc oxide (ZnO) is formed on a substrate 12 made of glass, organic film, ceramics, stainless steel or the like by a known method such as vacuum deposition, CVD, or sputtering (see FIG. Fig. 5-1 (a)).

  After forming the light reflection side transparent electrode layer 42A, the first etching step is performed (FIG. 5-1 (b)). In the first etching step, a concavo-convex shape is formed on the surface of the light reflection side transparent electrode layer 42A by etching using an alkaline solution to form a surface concavo-convex structure 61. Among the concave and convex portions formed by this etching, the depth to the bottom is deeper than many other concave portions, and the aspect ratio of the depth to the bottom with respect to the opening diameter on the surface side is extremely large. Large depressions are sparsely present. As will be described later, in a later step, etching is performed so as to widen the opening diameter of the deep recess. Therefore, hereinafter, this deep recess is referred to as an etching starting point 71.

  As the alkaline solution used for etching in the first etching step, for example, potassium hydroxide aqueous solution, sodium hydroxide aqueous solution, calcium hydroxide aqueous solution, barium hydroxide aqueous solution and the like are preferable.

  Further, the light reflecting side transparent electrode layer 42A may be annealed before and after etching with an alkaline solution. By performing the annealing, the crystal grain size and crystal orientation of the light reflecting side transparent electrode layer 42A can be changed, and the etching rate can be adjusted. Further, examples of the etching method include an immersion method and a spray method using a shower nozzle, but are not limited thereto.

  When etching is performed using an alkaline solution, the opening diameter of the formed recess tends to be small, unlike when etching is performed using an acidic solution. Therefore, the opening diameter of the recess in the surface uneven structure 61 is preferably 50 nm to 500 nm, and the depth to the bottom of the recess at this time is preferably 100 nm to 1 μm. Moreover, it is preferable that the depth of the recessed part which is the etching starting point 71 becomes a dimension 1.1 to 10 times the opening diameter of this recessed part.

The density and shape of the etching starting point 71 depend on the film forming conditions and the etching conditions of the light reflection side transparent electrode layer 42A. The light reflection side transparent electrode layer 42A is preferably formed under film forming conditions such that the etching starting point 71 is a film formed at a rate of 10 ³ to 10 ⁶ in 1 mm ² .

  After the surface concavo-convex structure 61 and the etching starting point 71 are formed on the surface of the light reflecting transparent electrode layer 42A by etching with an alkaline solution, a second etching step is performed (FIG. 5-1 (c)). In the second etching step, the opening diameter of the concave portion of the surface concavo-convex structure 61 is increased around the etching starting point 71 by etching using an acidic solution. As the acidic solution used for etching in the second etching step, for example, an aqueous hydrochloric acid solution, an aqueous nitric acid solution, an aqueous sulfuric acid solution, an aqueous acetic acid solution, and the like are preferable.

  When etching is performed using an acidic solution, unlike the case where etching is performed using an alkaline solution, the opening diameter of the formed recess tends to be large. For this reason, the opening diameter of the concave portion of the final surface uneven structure 62 is preferably, for example, 100 nm to 10 μm, and more preferably 1 μm to 10 μm. In this case, the depth to the bottom of the recess is preferably 100 nm to 1 μm. Moreover, it is more preferable that the depth dimension of the recess is 0.1 to 1 times the opening diameter of the recess.

  Further, the light reflecting transparent electrode layer 42A may be annealed before and after etching with an acidic solution. By performing the annealing, the crystal grain size and crystal orientation of the light reflecting side transparent electrode layer 42A can be changed, and the etching rate can be adjusted.

  Furthermore, in the case of Embodiment 2, it is not necessary for the light reflection side transparent electrode layer 42A to have a function of taking out the current photoelectrically converted by the thin film silicon photoelectric conversion unit 3. For this reason, there is no problem even if a pinhole or the like occurs in the light reflection side transparent electrode layer 42A by etching with an acidic solution, and there is an advantage that control of wet etching is easier than in the case of the first embodiment.

  As described above, in the second embodiment, first, a deep recess (etching starting point 71) is formed in the vertical direction in the light reflection side transparent electrode layer 42A using an alkaline etching solution. Then, the film surface of the light reflection side transparent electrode layer 42A is etched using an acidic etching solution to greatly widen the opening diameter of the deep recess (etching starting point 71). By performing such a process, the substrate for a photoelectric conversion device on which the light reflection side transparent electrode layer 42A having a good light confinement effect is formed can be formed by a simple process. And since the recessed part whose opening diameter is 1 micrometer or more can be formed by said process, especially the board | substrate for photoelectric conversion apparatuses which can scatter the light of visible light-infrared light region favorably is formed by simple process. Can do.

  Next, a manufacturing method of the silicon-based thin film photoelectric conversion device according to the second embodiment using this photoelectric conversion device substrate will be described. First, the light reflection side metal electrode layer 52 is formed by a known method on the light reflection side transparent electrode layer 42A of the substrate for a photoelectric conversion device (FIG. 5-1 (d)). For example, the light reflection side metal electrode layer 52 made of a silver (Ag) film having a high reflectance is formed on the light reflection side transparent electrode layer 42A by a sputtering method. The surface shape of the light reflection side metal electrode layer 52 is a shape reflecting the uneven shape which is the surface shape of the light reflection side transparent electrode layer 42A.

  Next, the light reflection side transparent electrode layer 42B is formed on the light reflection side metal electrode layer 52 by a known method (FIG. 5-1 (d)). For example, the light reflection side transparent electrode layer 42B made of a zinc oxide (ZnO) film is formed on the light reflection side metal electrode layer 52 by a sputtering method. Further, as a film formation method, another film formation method such as a CVD method may be used. The surface shape of the light reflection side transparent electrode layer 42 </ b> B is a shape reflecting the uneven shape that is the surface shape of the light reflection side metal electrode layer 52.

  Next, the thin film silicon-based photoelectric conversion unit 3 is formed on the light reflection side transparent electrode layer 42B by, for example, the CVD method (FIG. 5-2 (e)). As the thin film silicon-based photoelectric conversion unit 3, for example, a p-type hydrogenated microcrystalline silicon (μc-Si: H) layer, an i-type hydrogenated microcrystalline silicon (μc-Si) in order from the light reflection side transparent electrode layer 42B side. : H) layer and n-type hydrogenated microcrystalline silicon (μc-Si: H) layer are sequentially stacked. The surface shape of the thin-film silicon-based photoelectric conversion unit 3 is a shape that reflects the uneven shape that is the surface shape of the light reflection side transparent electrode layer 42B.

Next, the light incident side transparent electrode layer 22 is formed on the thin film silicon photoelectric conversion unit 3 by a known method (FIG. 5-2 (f)). For example, the light incident side transparent electrode layer 22 made of a tin oxide (SnO ₂ ) film is formed on the thin film silicon-based photoelectric conversion unit 3 by a sputtering method. Further, as a film formation method, another film formation method such as a CVD method may be used.

  Then, the grid electrode 84 is formed on a part of the light incident side transparent electrode layer 22 by a known method (FIG. 5F). For example, a line-shaped grid electrode 84 made of aluminum (Al) is formed on a part of the light incident side transparent electrode layer 22 by a sputtering method. With the above processing, the silicon-based thin film photoelectric conversion device according to the second embodiment shown in FIG. 4 is obtained.

  As described above, in the second embodiment, in the first etching process, an alkaline etching solution is used to form a deep recess (etching starting point 71) in the vertical direction on the film surface of the light reflection side transparent electrode layer 42A. Then, in the second etching step, the film surface of the light reflection side transparent electrode layer 42A is etched using an acidic etching solution, and the opening diameter of the deep concave portion (etching starting point 71) is greatly widened. By performing such a process, the substrate for a photoelectric conversion device on which the light reflection side transparent electrode layer 42A having a texture structure having a good light confinement effect is formed can be formed at a low cost by a simple process. . And since the recessed part whose opening diameter is 1 micrometer or more can be formed by said process, especially the board | substrate for photoelectric conversion apparatuses which can scatter the light of visible light-infrared light region favorably is formed by simple process. Can do.

  And since a silicon-based thin film photoelectric conversion device is produced using this substrate for a photoelectric conversion device, light in the visible light to infrared light region can be scattered well, and a good light confinement effect can be obtained in all wavelength regions. Thus, a photoelectric conversion device having high photoelectric conversion efficiency can be obtained.

EXAMPLES Next, the present invention will be specifically described using examples. First, a substrate for a photoelectric conversion device according to an example was manufactured by the method for manufacturing a silicon-based thin film photoelectric conversion device described in Embodiment 1, and a silicon-based thin film photoelectric conversion device was manufactured using the substrate. Moreover, as a comparative object, the substrates for photoelectric conversion devices according to Comparative Example 1 and Comparative Example 2 under the same conditions as in Examples except that the etching solution and etching time used in the first etching process and the second etching process were changed. And a silicon-based thin film photoelectric conversion device was manufactured using this. Table 1 shows etching solution conditions and Table 2 shows etching time conditions in the production of silicon-based thin film photoelectric conversion devices according to Examples and Comparative Examples.

  In Embodiment 1, Comparative Example 1 and Comparative Example 2, zinc oxide (ZnO) doped with aluminum (Al) was used as the material for the light incident side transparent electrode layer 21. As the etching solution, an aqueous potassium hydroxide solution (KOH) was used in the first etching step, and hydrochloric acid (HCl) was used in the second etching step. All etching temperatures were 25 degrees, and an immersion method was used as an etching method.

  FIG. 6 is a cross-sectional view schematically showing how the light incident side transparent electrode layer 23 according to Comparative Example 1 is etched. In the manufacture of the silicon-based thin film photoelectric conversion device of Comparative Example 1, after the light incident side transparent electrode layer 23 was formed on the substrate 11 (FIG. 6A), the conditions shown in Tables 1 and 2 were used. 1 was performed (FIG. 6B). In the first etching process of Comparative Example 1, a surface uneven structure 81 having the same shape as that of the example was formed. Also in this case, the concave-convex concave portion has a deeper depth to the bottom than many other concave portions and an extremely large aspect ratio of the depth to the bottom with respect to the opening diameter on the surface side. Exist sparsely. Here, this deep recess is referred to as an etching starting point 82.

  Next, the second etching process was performed under the conditions shown in Table 1 and Table 2 (FIG. 6C). In the second etching process of Comparative Example 1, the surface uneven structure 83 in which the depths of the etching start point 71 and other recesses are deep is formed. However, the recesses of the surface uneven structure 81 centering on the etching start point 82 are opened. No increase in caliber occurred. That is, the surface uneven | corrugated shape similar to an Example was not formed. The scanning electron micrograph which shows the surface state after etching the light incident side transparent electrode layer concerning an Example is shown in FIG. FIG. 8 is a scanning electron micrograph showing the surface state of the light incident side transparent electrode layer according to the example after the etching process. Moreover, the scanning electron micrograph which shows the surface state after etching the light incident side transparent electrode layer concerning the comparative example 1 is shown to Fig.9 (a). FIG. 9A is a scanning electron micrograph showing the surface state of the light incident side transparent electrode layer according to Comparative Example 1 after the etching process.

  FIG. 7 is a cross-sectional view schematically showing how the light incident side transparent electrode layer 24 according to Comparative Example 2 is etched. In the manufacture of the silicon-based thin film photoelectric conversion device of Comparative Example 2, after the light incident side transparent electrode layer 24 was formed on the substrate 11 (FIG. 7A), the conditions shown in Tables 1 and 2 were used. 1 was performed (FIG. 7B). In the first etching process of Comparative Example 2, a surface uneven structure 91 having a shape different from that of the example was formed. In this case, concave portions having substantially the same opening diameter and depth are formed uniformly on the surface of the light incident side transparent electrode layer 24, and these concave portions serve as etching starting points 92.

  Next, the second etching process was performed under the conditions shown in Table 1 and Table 2 (FIG. 7C). In the second etching step of Comparative Example 2, a concave portion that is finer than this is formed on the surface of the concave portion formed in the first etching step, and the surface uneven structure 93 in which the height of the concave portion is reduced is formed. It was done. That is, the surface uneven | corrugated shape similar to an Example was not formed. A scanning electron micrograph showing the surface state after etching the light incident side transparent electrode layer 24 according to Comparative Example 2 is shown in FIG. FIG. 9B is a scanning electron micrograph showing the surface state of the light incident side transparent electrode layer according to Comparative Example 2 after the etching process.

  The haze ratio of the light incident side transparent electrode layer 21 with respect to light having a wavelength of 800 nm was measured at the time when the substrates for photoelectric conversion devices were produced in Examples, Comparative Examples 1 and 2. The results are shown in Table 3. The haze ratio is an index indicating how much of the incident light is scattered. The higher the haze ratio, the higher the effect of light confinement, and the short circuit current density when the photoelectric conversion device is made increases.

  As can be seen from Table 3, the light incident side transparent electrode layer 21 of the substrate for a photoelectric conversion device according to the example using an alkaline solution for etching in the first etching and an acidic solution for etching in the second etching was used. The haze ratio has the highest light confinement effect. On the other hand, the haze ratio of the light incident side transparent electrode layer 23 of the photoelectric conversion device substrate according to Comparative Example 1 using the alkaline solution for both the first etching and the second etching is greatly reduced as compared with the example. Moreover, although the haze rate of the light-incidence side transparent electrode layer 24 of the substrate for photoelectric conversion devices according to the comparative example 2 using the acidic solution for both the first etching and the second etching is larger than that of the comparative example 1, it is compared with the examples. It has decreased greatly.

  FIG. 10 shows the haze ratio of the light incident side transparent electrode layer 21 of the photoelectric conversion device substrate manufactured in the example. FIG. 10 is a characteristic diagram showing the haze ratio of the light incident side transparent electrode layer 21 of the photoelectric conversion device substrate according to the example. Further, the haze ratio of the light incident side transparent electrode layer 23 of the photoelectric conversion device substrate manufactured in Comparative Example 1 is shown in FIG. 11, and the haze ratio of the light incident side transparent electrode layer 24 of the photoelectric conversion device substrate manufactured in Comparative Example 2 is shown in FIG. The rate is shown in FIG. FIG. 11 is a characteristic diagram showing the haze ratio of the light incident side transparent electrode layer 23 of the photoelectric conversion device substrate according to Comparative Example 1. 12 is a characteristic diagram showing the haze ratio of the light incident side transparent electrode layer 24 of the photoelectric conversion device substrate according to Comparative Example 2. FIG.

  In the first etching of the embodiment, the etching starting point 71 and the surface uneven structure 61 are formed on the surface of the light incident side transparent electrode layer 21, and light having a wavelength of 400 nm to 800 nm is scattered. In this case, the haze ratio is the measured haze ratio value 101 in FIG. In the second etching, the opening diameter of the concave portion increases with the etching starting point 71 as the center. The haze rate in this case is as shown by the measured haze rate 102 in FIG.

  In the first etching of Comparative Example 1, since the etching conditions are the same as in the example, the surface uneven structure 81 and the etching starting point 82 similar to those in the example are formed on the surface of the light incident side transparent electrode layer 23, Light having a wavelength of 400 nm to 800 nm is scattered. The haze rate in this case is as shown in the measured haze rate value 103 in FIG. In the second etching, since the etching starting point 82 is further etched perpendicularly to the film surface, the depth of the recess is further increased, but the opening diameter of the recess is not increased. For this reason, only light with a wavelength of 400 nm to 800 nm is scattered, and the haze ratio in this case is like the measured haze ratio 104 in FIG.

  In the first etching of Comparative Example 2, the surface uneven structure 91 and the etching starting point 92 are formed on the light incident side transparent electrode layer 24. In the first etching of Comparative Example 2, since an acidic etching solution is used, the opening diameter of the recesses is larger than that of the alkaline etching solution, and light having a wavelength of 400 nm to 1200 nm is scattered. The haze ratio in this case is as shown in the measured haze ratio 105 of FIG. In the second etching, the etching starting point 92 is further etched, but the concentration of the acidic etching solution is reduced, and a finer uneven shape is formed than in the first etching, so that light scattering with a wavelength of 400 to 800 nm is performed. However, the light scattering at a wavelength of 800 to 1200 nm is weakened, and the haze ratio in this case is the measured haze ratio 106 of FIG.

  From these facts, it is understood that the light incident side transparent electrode layer 21 of the photoelectric conversion device substrate according to the example can obtain a good light confinement effect in the entire wavelength region.

  Next, the thin-film silicon-based photoelectric conversion unit 3 and the light reflection side transparent electrode layer 41 are formed on the light incident side transparent electrode layers 21, 23, and 24 of the photoelectric conversion device substrate according to the example, the comparative example 1 and the comparative example 2. Then, the silicon-based thin film photoelectric conversion device was manufactured by sequentially laminating the light reflection side metal electrode layer 51. Table 4 shows the film forming conditions in the silicon-based thin film photoelectric conversion devices according to the example, the comparative example 1, and the comparative example 2.

  Table 5 shows standard values of the short-circuit current density of the silicon-based thin film photoelectric conversion devices according to Examples, Comparative Examples 1 and 2 manufactured as described above. Here, the standard value is the short-circuit current density of the silicon-based thin film photoelectric conversion device according to the example, and the short-circuit current density of the example is calculated as 1. The quantum efficiency of each silicon-based thin film photoelectric conversion device is shown in FIG. FIG. 13 is a characteristic diagram showing the quantum efficiency of the silicon-based thin film photoelectric conversion devices according to the example, the comparative example 1, and the comparative example 2. In FIG. 13, the quantum efficiency measurement value 107 of the silicon-based thin film photoelectric conversion device according to the example, the quantum efficiency measurement value 108 of the silicon-based thin film photoelectric conversion device according to Comparative Example 1, and the silicon-based thin film photoelectric conversion device according to Comparative Example 2 The measured quantum efficiency values 109 are shown.

  As shown in Table 5 and FIG. 13, compared to Comparative Example 1 and Comparative Example 2, the silicon-based thin film photoelectric conversion device of the example shows a higher short-circuit current density. Therefore, in the silicon-based thin film photoelectric conversion device according to the example, a good light confinement effect is obtained in all wavelength regions, and a photoelectric conversion device having high photoelectric conversion efficiency is realized.

  As described above, the method for manufacturing a substrate for a photoelectric conversion device and the method for manufacturing a photoelectric conversion device capable of realizing the photoelectric conversion device according to the present invention can obtain a good light confinement effect in all wavelength regions, and have high photoelectric conversion efficiency. It is useful for realizing a photoelectric conversion device having

DESCRIPTION OF SYMBOLS 3 Thin film silicon type photoelectric conversion unit 11 Substrate 12 Substrate 21 Light incident side transparent electrode layer 22 Light incident side transparent electrode layer 23 Light incident side transparent electrode layer 24 Light incident side transparent electrode layer 41 Light reflecting side transparent electrode layer 42A Light reflecting side Transparent electrode layer 42B Light reflection side transparent electrode layer 51 Light reflection side metal electrode layer 52 Light reflection side metal electrode layer 61 Surface uneven structure 62 Surface uneven structure 71 Etching start point 81 Surface uneven structure 82 Etching start point 84 Grid electrode 91 Surface uneven structure 92 Etching start point 101 Haze rate measured value 102 Haze rate measured value 103 Haze rate measured value 104 Haze rate measured value 105 Haze rate measured value 106 Haze rate measured value 107 Quantum efficiency measured value 108 Quantum efficiency measured value 109 Quantum efficiency measured value

Claims (9)

A method for producing a substrate for a photoelectric conversion device comprising an electrode layer made of a conductive material and having an uneven shape on the surface thereof,
A first step of forming a conductive material film on the substrate to form the electrode layer;
Etching the electrode layer formed on the substrate with an alkaline etching solution to form a plurality of first recesses having a depth dimension larger than the opening diameter dimension on the surface of the electrode layer. Two steps,
Etching is performed using an acidic etching solution on the electrode layer in which the first recess is formed, so that the opening diameter of the first recess is greatly widened to form a second recess on the surface of the electrode layer. Process,
The manufacturing method of the board | substrate for photoelectric conversion apparatuses characterized by including. In the first step, the conductive material film is formed under a film forming condition in which the first recess is formed in a ratio of 1 × 10 ³ to 1 × 10 ⁶ in 1 mm ² in the second step. ,
The method for producing a substrate for a photoelectric conversion device according to claim 1. The conductive material film is a zinc oxide film, a zinc oxide film doped with indium and gallium, a zinc oxide film doped with indium or a transparent conductive film,
In the first step, adjusting at least one of a film formation temperature condition of the zinc oxide film and an addition amount condition of impurities doped into the zinc oxide film;
The method for producing a substrate for a photoelectric conversion device according to claim 1, wherein: The depth dimension of the first recess is 1.1 to 10 times the opening diameter of the first recess;
The depth dimension of the second recess is 0.1 to 1 times the opening diameter of the second recess;
The manufacturing method of the board | substrate for photoelectric conversion apparatuses as described in any one of Claims 1-3 characterized by these. Including a step of annealing the electrode layer between the first step and the second step;
The manufacturing method of the board | substrate for photoelectric conversion apparatuses as described in any one of Claims 1-4 characterized by these. Including a step of annealing the electrode layer between the second step and the third step;
The manufacturing method of the board | substrate for photoelectric conversion apparatuses as described in any one of Claims 1-5 characterized by these. Including a step of performing an annealing process on the electrode layer after the second step;
The method for producing a substrate for a photoelectric conversion device according to any one of claims 1 to 6. The electrode layer has translucency,
The method for producing a substrate for a photoelectric conversion device according to claim 1, wherein: Forming the photoelectric conversion device substrate by the method according to claim 1;
Forming a photoelectric conversion unit including a semiconductor layer that performs photoelectric conversion on the electrode layer of the substrate for the photoelectric conversion device;
An electrode layer forming step of forming another electrode layer paired with the electrode layer on the photoelectric conversion unit;
Including
A method of manufacturing a photoelectric conversion device characterized by the above.