JP2012204646A - Manufacturing method of substrate for thin film photoelectric conversion device and manufacturing method of thin film photoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a manufacturing method of a substrate for thin film photoelectric conversion device capable of suppressing the occurrence of defects in a photoelectric conversion layer formed on an upper layer while enhancing the photoelectric conversion efficiency of a thin film photoelectric conversion device.SOLUTION: The manufacturing method of a substrate for thin film photoelectric conversion device includes a first step for forming an electrode film 3 on a substrate 2, a second step for forming first protrusions and recesses 4 on the surface of the electrode film 3, and a third step for forming second protrusions and recesses 5, having a period shorter than that of the first protrusions and recesses 4, on the slopes of the first protrusions and recesses 4 by irradiating the surface of the first protrusions and recesses 4 with an energy beam 6.

Description

  The present invention relates to a method for manufacturing a substrate for a thin film photoelectric conversion device and a method for manufacturing a thin film photoelectric conversion device, and in particular, a method for manufacturing a substrate for a thin film photoelectric conversion device having a concavo-convex shape of a transparent conductive film and a thin film photoelectric conversion device. It relates to the manufacturing method.

  A conventional thin film photoelectric conversion device includes a thin film solar cell that generates a photovoltaic force in a thin film semiconductor layer by light incidence from the other surface side of the substrate. In the thin film solar cell, for example, a transparent electrode, a thin film semiconductor layer as a photoelectric conversion layer, and a reflective conductive film as a back electrode are sequentially formed on one surface side of a substrate. A plurality of such thin film solar cells are arranged with a predetermined distance between adjacent cells, and are electrically connected in series to form a thin film photoelectric conversion device (thin film solar cell module). Moreover, the photoelectric converting layer between adjacent thin film photovoltaic cells is electrically separated by the separation groove.

  In such a thin film photoelectric conversion device, sunlight utilization efficiency is improved by scattering sunlight transmitted through the substrate and the transparent electrode within the photoelectric conversion layer. And in order to scatter sunlight, the unevenness | corrugation called a texture is formed in the surface of the transparent conductive film which comprises the transparent electrode.

  Tandem solar cells, which are composed of a stack of amorphous silicon solar cells and microcrystalline silicon solar cells, which have been actively developed in recent years, absorb sunlight in a wide wavelength range, It is necessary to scatter a wide range of light from a short wavelength to a long wavelength by the texture of the film surface. Light is scattered when the texture irregularity period is equal to the wavelength. Therefore, in the texture, light in the short wavelength region is scattered by the unevenness of the short unevenness period, and light in the long wavelength region is scattered by the unevenness of the long unevenness cycle.

  For example, Patent Document 1 discloses a method of forming a transparent conductive film having a double texture structure with different irregularities by performing an etching process for forming irregularities twice. As a result, light in a wide wavelength range is scattered by unevenness having different unevenness periods.

  Further, Patent Document 2 discloses a similar method in which an island-like ridge that first becomes irregularities with a long irregularity cycle is formed by an atmospheric pressure CVD (Chemical Vapor Deposition) method, and then a continuous film having irregularities with a short irregularity cycle is formed. The method of forming the transparent conductive film which has a double texture structure by forming by is shown. Thereby, the transparent conductive film which has the manufacturing method equivalent to the conventional transparent conductive film and scatters light in a wide wavelength range is formed.

JP 2004-119491 A JP 2005-347490 A

  However, in the method of forming a double texture in two etching steps as in the above-mentioned Patent Document 1, the etching rate varies when forming unevenness with a short unevenness period, and thus the unevenness with a long unevenness period disappears. was there. Further, since irregularities having a short irregularity period occur at irregular positions, it is difficult to form irregularities having a desired irregularity period.

  On the other hand, by forming the transparent conductive film and the double texture structure by two-time film formation by the CVD method as in Patent Document 2 described above, it is possible to suppress variations in the uneven shape having a short uneven cycle. However, since the convexity of the irregularities with a long irregularity period composed of small ridges becomes a steep valley, it is not suitable for photoelectric conversion layers formed on transparent conductive films, especially microcrystalline silicon films where crystallinity is important. There was a problem that a defect with the base point occurred and the power generation characteristics deteriorated. In addition, there is a problem that the manufacturing method becomes complicated due to a plurality of film forming steps.

  The present invention has been made in view of the above, and manufacture of a substrate for a thin film photoelectric conversion device capable of suppressing generation of defects in a photoelectric conversion layer formed in an upper layer and improving the photoelectric conversion efficiency of the thin film photoelectric conversion device. It is an object to obtain a method and a manufacturing method of a thin film photoelectric conversion device.

  In order to solve the above-described problems and achieve the object, a manufacturing method of a substrate for a thin film photoelectric conversion device according to the present invention includes a first step of forming an electrode film on the substrate, and a first step on the surface of the electrode film. A second step of forming the unevenness and forming a second unevenness having a shorter unevenness period than the first unevenness on the slope of the first unevenness by irradiating the surface of the first unevenness with an energy beam And a third step.

  According to the present invention, there is an effect that a substrate for a thin film photoelectric conversion device capable of suppressing generation of defects in the photoelectric conversion layer formed in the upper layer and improving the photoelectric conversion efficiency of the thin film photoelectric conversion device is obtained.

FIG. 1 is a cross-sectional view schematically showing a schematic configuration of a thin film photoelectric conversion device substrate manufactured by the method for manufacturing a thin film photoelectric conversion device substrate according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining a method of forming irregularities using pulsed laser light irradiation according to the first embodiment of the present invention. FIG. 3 is a diagram for explaining a method of forming irregularities using pulsed laser light irradiation according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating the procedure of the method for manufacturing the substrate for the thin film photoelectric conversion device according to the first embodiment of the present invention. FIG. 5: is sectional drawing which shows typically schematic structure of the board | substrate for thin film photoelectric conversion apparatuses manufactured by the manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses concerning Embodiment 2 of this invention. FIG. 6 is a diagram for explaining a method of forming irregularities using ion beam irradiation according to the second embodiment of the present invention. FIG. 7: is sectional drawing explaining the procedure of the manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses concerning Embodiment 2 of this invention. FIG. 8: is principal part sectional drawing which shows typically schematic structure of the photoelectric conversion apparatus using the board | substrate for thin film photoelectric conversion apparatuses manufactured by the manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses concerning Embodiment 1. FIG.

  EMBODIMENT OF THE INVENTION Below, embodiment of the manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses concerning this invention and the manufacturing method of a thin film 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 cross-sectional view schematically showing a schematic configuration of a thin film photoelectric conversion device substrate 1 manufactured by the method for manufacturing a thin film photoelectric conversion device substrate according to the first embodiment of the present invention. The thin film photoelectric conversion device substrate 1 is a substrate including a translucent insulating substrate 2 and a transparent electrode film 3. The transparent electrode film 3 has, on the surface thereof, a first unevenness 4 having a long unevenness period and a second unevenness 5 having a short unevenness period. For example, when the uneven period of the first unevenness 4 is the first period and the uneven period of the second unevenness 5 is the second period, the first period is longer than the second period. That is, the transparent electrode film 3 has a double texture structure with different irregularities on its surface. The transparent electrode film 3 having such a double texture structure scatters light in the long wavelength region by the first unevenness 4 having a long unevenness period, and scatters light in the short wavelength region by the second unevenness 5 having a short unevenness period. It is possible to make it.

  The first irregularities 4 formed on the surface of the transparent electrode film 3 are mainly composed of irregularities having an irregularity period of about 1 μm to 2 μm. The 2nd unevenness | corrugation 5 formed in the inclined surface of the 1st unevenness | corrugation 4 is mainly comprised by the unevenness | corrugation whose uneven | corrugated period is about 100 nm-about 200 nm.

  In the thin film photoelectric conversion device substrate 1, the second unevenness 5 is formed on the film surface of the first unevenness 4 using pulsed laser light irradiation. When the laser beam is scanned and irradiated with a pulsed laser beam having a certain wavelength, which is an energy beam, with a part of the beam irradiation area overlapped, the outermost surface of the film is melted and re-solidified to form irregularities with a constant irregularity cycle. The A periodic uneven structure formed by this phenomenon is called Laser-Induced Periodic Surface Structure (LIPSS). Although the generation mechanism of LIPSS is not completely elucidated, it is generally assumed that the uneven period depends on the wavelength of the laser light and the angle with respect to the irradiation surface. The concavo-convex cycle is represented by the following formula (1) and formula (2). Equation (1) corresponds to the case where the number of times of laser irradiation is small (10 times). Formula (2) corresponds to the case where the number of times of laser irradiation is large (up to 100 times).

In the above formulas (1) and (2), L is the concave-convex period, λ is the laser beam wavelength, n _{0, λ} is the refractive index of the film at the wavelength λ, and θ is relative to the normal direction of the film surface. The incident angle of laser light is shown. For example, when laser light is irradiated perpendicularly to the film surface, θ = 0 °. Here, when a pulse laser beam having a wavelength of 532 nm is irradiated onto a film having a refractive index of 2 perpendicular to the film surface, the concavo-convex period of LIPSS is ˜260 nm. Moreover, when only the irradiation angle is changed to 45 ° and the number of superpositions is about 10 times, the concavo-convex period of LIPSS is ˜150 nm.

  Next, a description will be given of a case where the unevenness forming method by pulse laser irradiation as described above is applied to the film surface of the first unevenness 4. The wavelength of the pulsed laser light is preferably in the range of 200 nm to 1000 nm. By controlling the wavelength of the pulsed laser beam 6, the uneven period of the second unevenness 5 can be controlled. When the surface of the first unevenness 4 is scanned and irradiated with the pulse laser beam 6, the second unevenness 5 having an unevenness period equal to or less than the laser wavelength of the pulsed laser light 6 is formed on the slope of the first unevenness 4. The Therefore, by setting the wavelength of the pulse laser light in the range of 200 nm to 1000 nm, the second unevenness 5 having the unevenness period of ~ 1000 nm can be formed by controlling the unevenness period. In addition, when the wavelength of the pulse laser beam is smaller than 200 nm, the formed irregularity period is 100 nm or less, and light contained in sunlight is hardly scattered, which is not desirable. When the wavelength of the pulsed laser beam is larger than 1000 nm, the uneven period to be formed is 1000 nm or more, and light with a wavelength of 1000 nm or less is hardly scattered, which is not desirable.

  As the light source of the pulse laser beam, for example, a fundamental wave of an Nd: YAG laser, a second harmonic of an Nd: YAG laser, a third harmonic of an Nd: YAG laser, an excimer laser, an ultraviolet laser, or the like can be used. By using these light sources, the second unevenness 5 having an unevenness period of several tens to several hundreds of nanometers can be formed.

  FIG. 2 is a diagram for explaining a method of forming irregularities using pulsed laser beam irradiation, and schematically shows a start state of irradiation with pulsed laser light 6 on the surface of the transparent electrode film 3 on which the first irregularities 4 are formed. FIG. In the 1st unevenness | corrugation 4 shown in FIG. 2, the angle | corner of protrusion (convex part) head top part is -45 degrees. As shown in FIG. 2, the pulse laser beam 6 is irradiated on the surface of the first unevenness 4 perpendicularly to the substrate surface of the translucent insulating substrate 2.

  FIG. 3 is a diagram for explaining a method of forming irregularities using pulsed laser beam irradiation, in which the surface of the transparent electrode film 3 on which the first irregularities 4 are formed is scanned with pulsed laser light 6. It is sectional drawing which shows this typically. As shown in FIG. 3, the pulsed laser beam 6 is scanned and irradiated on the surface of the first unevenness 4 perpendicular to the substrate surface of the translucent insulating substrate 2.

  The curve group in the figure indicates a beam intensity distribution curve representing the beam intensity distribution of the pulsed laser light 6, and the arrow A indicates the scanning direction of the beam of the pulsed laser light 6. The direction of arrow A is the surface direction of the transparent electrode film 3. In addition, the number of irradiation times of the pulse laser beam 6 is shown on the beam intensity distribution curve in the figure. The number of overlaps of the beam irradiation region of the pulse laser beam 6 was five. In the (N + 1) th pulse laser beam 6 beam irradiation following the Nth pulse laser beam 6 beam irradiation, the irradiation region is shifted by 20%, so that 80% of the irradiation region is superimposed. If the surface of the transparent electrode film 3 is continuously irradiated with the pulsed laser beam 6 while shifting the irradiation position at the same rate, the irradiation area overlaps with the Nth irradiation in the (N + 5) th irradiation.

  When the surface of the transparent electrode film 3 is scanned and irradiated with the pulse laser beam 6 in this manner, the unevenness equal to or less than the laser wavelength of the pulsed laser light 6 is formed on the slope of the first unevenness 4 as shown in FIG. Second irregularities 5 having a period are formed. For example, when an ultraviolet laser having a wavelength of about 300 nm is used as the light source of the pulse laser beam 6, the refractive index of the transparent electrode film 3 is ˜2, as will be described below, so that the concavo-convex period of the second concavo-convex 5 is about 150 nm. This is shorter than the uneven period of the first unevenness 4. Therefore, by forming the first unevenness 4 with a long unevenness period of about 1 μm to 2 μm, a double texture structure composed of the first unevenness 4 with a long unevenness period and the second unevenness 5 with a short unevenness period is formed. It can be formed on the surface of the transparent electrode film 3.

  When an excimer laser having a wavelength of about 300 nm is used as the light source of the pulse laser beam 6, the refractive index of the transparent electrode film 3 is ˜2, so that the concave / convex period of the second concave / convex 5 is about several tens of nm. It becomes shorter than the concave / convex period of one concave / convex 4. Therefore, by forming the first unevenness 4 with a long unevenness period of about 1 μm to 2 μm, a double texture structure composed of the first unevenness 4 with a long unevenness period and the second unevenness 5 with a short unevenness period is formed. It can be formed on the surface of the transparent electrode film 3.

  Next, the manufacturing method of the board | substrate 1 for thin film photoelectric conversion apparatuses using the formation method of the unevenness | corrugation by pulse laser irradiation demonstrated above is demonstrated. FIG. 4: is sectional drawing explaining the procedure of the manufacturing method of the board | substrate 1 for thin film photoelectric conversion devices concerning Embodiment 1 of this invention. First, as shown in FIG. 4A, the transparent electrode film 3 is formed on the translucent insulating substrate 2. In a substrate for a thin film photoelectric conversion device used for a super straight type thin film photoelectric conversion device, a light-transmitting insulating substrate is used as a substrate, and a transparent electrode film is used as a first electrode.

  The light-transmitting insulating substrate 2 is made of, for example, transparent glass or resin as a substrate having light-transmitting and insulating properties, and as an impurity blocking layer on these materials, an undercoat such as silicon oxide by sputtering or the like. What provided the layer can be used.

For the transparent electrode film 3, a transparent conductive film such as zinc oxide (ZnO), indium tin oxide (ITO), tin oxide (SnO ₂ ), etc. having high light transmittance is used as the transparent conductive film. And aluminum (Al), gallium (Ga), indium (In), boron (B), yttrium (Y), silicon (Si), zirconium (Zr), titanium (Ti), and manganese (Mn). A transparent conductive film to which at least one element selected from the group is added can be used. For forming the transparent electrode film 3, for example, a sputtering method or a thermal CVD method can be used. The film thickness of the transparent electrode film 3 is preferably about 0.5 μm to 1 μm in order to maintain conductivity.

  Next, as shown in FIG. 4B, first irregularities 4 having a long irregularity period are formed on the surface of the transparent electrode film 3. When the transparent electrode film 3 is a film formed by sputtering, such as ZnO or ITO, the surface becomes flat. Then, after the formation of the transparent electrode film 3, the first unevenness 4 is formed on the surface of the transparent electrode film 3 by chemically etching the surface of the transparent electrode film 3 with an acidic solution such as dilute hydrochloric acid. The concentration of dilute hydrochloric acid is preferably 0.1% or less. At this time, by appropriately selecting the formation conditions of the transparent electrode film 3 such as ZnO or ITO and the etching conditions with dilute hydrochloric acid, the uneven period of the main region of the first unevenness 4 can be set to several μm.

In addition, when the transparent electrode film 3 is a film formed by a thermal CVD method such as SnO ₂ , irregularities are generated on the surface when formed. Therefore, chemical etching of the surface with diluted hydrochloric acid or the like after the film formation is unnecessary as in the case where the transparent electrode film 3 is made of ZnO or ITO.

  After forming the first unevenness 4, the pulse laser beam 6 is scanned and irradiated in the direction of arrow B on the slope of the first unevenness 4 as shown in FIG. The direction of arrow B is the surface direction of the transparent electrode film 3. For example, on the surface of the transparent electrode film 3 on which the first unevenness 4 is formed, the pulsed laser beam 6 using the second harmonic of an Nd: YAG laser having a wavelength of 532 nm as a light source is used as described above. Scan irradiation is performed perpendicularly to the substrate surface. The number of times of irradiation with the pulsed laser light 6 is preferably about 10 in order to suppress a decrease in productivity.

When the pulse laser beam 6 is scanned and irradiated on the slope of the first unevenness 4 as described above, the second unevenness 5 having a short unevenness period is formed on the slope of the first unevenness 4 as shown in FIG. It is formed. Further, the refractive index of ZnO, ITO, SnO ₂ used for the transparent electrode film 3 is about 2, and the projection (convex portion) top angle of the first unevenness 4 is about 30 °, so that the pulse laser beam 6 The unevenness period of the second unevenness 5 formed by the irradiation is about 160 nm (≈532 nm / 3.4) from Equation (1), which is smaller than the unevenness period (˜1 μm) of the first unevenness 4. Become. Therefore, a double texture structure constituted by the first unevenness 4 having a long unevenness period and the second unevenness 5 having a short unevenness period is realized.

  The transparent electrode film 3 having a double texture structure formed in this manner scatters light in the long wavelength region by the first unevenness 4 having a long uneven period, and short wavelength region by the second unevenness 5 having a short uneven period. It becomes possible to scatter light.

  In the manufacturing method of the substrate for a thin film photoelectric conversion device according to the first embodiment described above, the surface of the first unevenness 4 having a long unevenness period is scanned and irradiated with the pulsed laser beam 6 on the slope of the first unevenness 4. The second unevenness 5 having a short unevenness period is selectively formed. And since the 2nd unevenness | corrugation 5 is mainly formed on the slope of the 1st unevenness | corrugation 4, the 1st unevenness | corrugation 4 with a long unevenness | corrugation period does not lose | disappear at the time of formation of the 2nd unevenness | corrugation 5, The 2nd unevenness | corrugation 5 can be formed with a desired uneven | corrugated period. Thereby, a double texture structure with good light scattering characteristics can be reliably formed on the surface of the transparent electrode film 3.

  Moreover, in the manufacturing method of the substrate for a thin film photoelectric conversion device according to the first embodiment, since the first unevenness 4 is formed by the chemical etching method, the inclination of the recess of the first unevenness 4 becomes gradual, and the first The generation of steep valleys on the surface of the unevenness 4 is suppressed. For this reason, when a photoelectric conversion layer such as a microcrystalline silicon film is formed on the thin film photoelectric conversion device substrate 1 manufactured by the manufacturing method of the present embodiment to form the photoelectric conversion device, the valleys of the first unevenness 4 There is no defect on the top, and a photoelectric conversion device with high power generation efficiency can be obtained.

  Moreover, in the manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses concerning Embodiment 1, since the film forming process at the time of formation of the transparent electrode film 3 is 1 time, a manufacturing method is simple.

  Therefore, according to the manufacturing method of the substrate for a thin film photoelectric conversion device according to the first embodiment, the thin film photoelectric conversion device capable of suppressing the generation of defects in the photoelectric conversion layer formed in the upper layer and improving the photoelectric conversion efficiency of the thin film photoelectric conversion device. There exists an effect that the board | substrate for converters is obtained.

Embodiment 2. FIG.
FIG. 5: is sectional drawing which shows typically schematic structure of the board | substrate 101 for thin film photoelectric conversion apparatuses manufactured by the manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses concerning Embodiment 2 of this invention. The thin film photoelectric conversion device substrate 101 is a substrate including a translucent insulating substrate 102 and a transparent electrode film 103. The transparent electrode film 103 has, on its surface, a first unevenness 104 with a long unevenness period and a second unevenness 105 with a short unevenness period. For example, when the uneven period of the first unevenness 104 is the first period and the uneven period of the second unevenness 105 is the second period, the first period is longer than the second period. That is, the transparent electrode film 103 has a double texture structure with different irregularities on its surface. The transparent electrode film 103 having such a double texture structure scatters light in the long wavelength region by the first unevenness 104 having a long unevenness period, and scatters light in the short wavelength region by the second unevenness 105 having a short unevenness period. It is possible to make it.

  The first unevenness 104 formed on the surface of the transparent electrode film 103 is mainly composed of unevenness having an unevenness period of about 1 μm to 2 μm. The 2nd unevenness | corrugation 105 formed in the inclined surface of the 1st unevenness | corrugation 104 is mainly comprised by the unevenness | corrugation whose uneven | corrugated period is about 100 nm-about 200 nm.

  In the thin film photoelectric conversion device substrate 101, the second unevenness 105 is formed on the film surface of the first unevenness 104 using ion beam irradiation. When an ion beam, which is an energy beam, is scanned and irradiated on the film surface, a competing process of sputtering and surface diffusion on the outermost surface of the film occurs, and irregularities with a constant irregularity period are formed. This phenomenon is called Ripple Pattern Formation. The generation mechanism of Ripple Pattern Formation has not been completely elucidated, but generally the uneven period formed by this phenomenon is about several hundred nm. The uneven period depends on the ion beam energy, flux (amount of ions entering per unit area / unit time), and irradiation angle. As the energy and flux of the ion beam are higher and the irradiation angle is smaller with respect to the film surface, irregularities with shorter irregularities are formed. In addition, when the ion beam is irradiated perpendicularly to the film surface, unevenness is hardly formed.

Next, a description will be given of a case where the unevenness forming method by ion beam irradiation as described above is applied to the film surface of the first unevenness 104. The ion beam may be a rare ion beam such as an argon ion beam using argon (Ar) ions as ions, a helium ion beam using helium (He) as ions, or a nitrogen molecular ion beam using nitrogen molecules (N ₂ ) as ions. A gas ion beam can be used. By using a rare gas ion beam, the ion beam can be easily formed and impurities can be prevented from being mixed into the transparent electrode film 103. A general-purpose ion implantation apparatus or the like is used for ion beam irradiation.

  FIG. 6 is a diagram for explaining a method of forming irregularities using ion beam irradiation, and schematically illustrates a state in which the surface of the transparent electrode film 103 on which the first irregularities 104 are formed is scanned with the ion beam 106. FIG. In the first unevenness 104 shown in FIG. 6, the angle of the protrusion (convex portion) head portion is ˜45 °. When the ion beam 106 is scan-irradiated perpendicularly to the substrate surface of the light-transmitting insulating substrate 102 by the same method as the scan irradiation of the pulsed laser light 6 in Embodiment 1, the above-described irradiation is performed. The angle is 45 °.

  When the ion beam 106 is scanned and irradiated on the surface of the transparent electrode film 103 in this way, the second unevenness 105 having an unevenness period of about several hundred nm is formed on the slope of the first unevenness 104 as shown in FIG. It is formed. In addition, the ion beam 106 is irradiated perpendicularly to the film surface at the top and valley of the first unevenness 104, and the second unevenness 105 is hardly formed. Therefore, by forming the first unevenness 104 with a long unevenness period of about 1 μm to 2 μm, a double texture structure composed of the first unevenness 104 with a long unevenness period and the second unevenness 105 with a short unevenness period is formed. It can be formed on the surface of the transparent electrode film 103.

  Next, a method for manufacturing the substrate 101 for a thin film photoelectric conversion device using the method for forming irregularities by ion beam irradiation described above will be described. FIG. 7: is sectional drawing explaining the procedure of the manufacturing method of the board | substrate 101 for thin film photoelectric conversion apparatuses concerning Embodiment 2 of this invention. First, as shown in FIG. 7A, a transparent electrode film 103 is formed on a translucent insulating substrate 102. In a substrate for a thin film photoelectric conversion device used for a super straight type thin film photoelectric conversion device, a light-transmitting insulating substrate is used as a substrate, and a transparent electrode film is used as a first electrode.

  The light-transmitting insulating substrate 102 is a transparent and insulating substrate, for example, transparent glass or resin, and as an impurity blocking layer on these materials, an undercoat such as silicon oxide by sputtering or the like. What provided the layer can be used.

The transparent electrode film 103 includes a transparent conductive film such as zinc oxide (ZnO), indium tin oxide (ITO), and tin oxide (SnO ₂ ) as a light-transmitting conductive film, and aluminum ( At least one selected from the group consisting of Al), gallium (Ga), indium (In), boron (B), yttrium (Y), silicon (Si), zirconium (Zr), titanium (Ti), manganese (Mn) A transparent conductive film to which more than one kind of element is added can be used. For forming the transparent electrode film 103, for example, a sputtering method or a thermal CVD method can be used. The film thickness of the transparent electrode film 103 is preferably about 0.5 μm to 1 μm in order to maintain conductivity.

  Next, as shown in FIG. 7B, a first unevenness 104 having a long unevenness period is formed on the surface of the transparent electrode film 103. When the transparent electrode film 103 is a film formed by sputtering, such as ZnO or ITO, the surface becomes flat. Then, after the formation of the transparent electrode film 103, the first unevenness 104 is formed on the surface of the transparent electrode film 103 by chemically etching the surface of the transparent electrode film 103 with an acidic solution such as dilute hydrochloric acid. The concentration of dilute hydrochloric acid is preferably 0.1% or less. At this time, by appropriately selecting the formation conditions of the transparent electrode film 103 such as ZnO or ITO and the etching conditions with dilute hydrochloric acid, the uneven period of the main region of the first unevenness 104 can be set to several μm.

In addition, when the transparent electrode film 103 is a film formed by a thermal CVD method such as SnO ₂ , irregularities are generated on the surface when formed. Therefore, chemical etching of the surface with dilute hydrochloric acid or the like after the film formation is unnecessary as in the case where the transparent electrode film 103 is made of ZnO or ITO.

  After the first unevenness 104 is formed, the ion beam 106 is scanned and irradiated in the direction of arrow C on the slope of the first unevenness 104 as shown in FIG. The direction of arrow C is the surface direction of the transparent electrode film 103. For example, an argon (Ar) ion beam having an acceleration voltage of 50 keV or less is scanned on the surface of the transparent electrode film 103 on which the first unevenness 104 is formed perpendicularly to the substrate surface of the translucent insulating substrate 102 as described above. Irradiate. The number of times of irradiation of the ion beam 106 is preferably about 10 in order to suppress a decrease in productivity.

  When the ion beam 106 is scanned and irradiated on the slope of the first unevenness 104 as described above, the second unevenness 105 having a short unevenness cycle is formed on the slope of the first unevenness 104 as shown in FIG. Is done. The unevenness period of the second unevenness 105 formed by irradiation with the ion beam 106 is several hundred nm, which is a value smaller than the unevenness period (˜1 μm) of the first unevenness 104. Therefore, a double texture structure constituted by the first unevenness 104 having a long unevenness period and the second unevenness 105 having a short unevenness period is realized.

  The transparent electrode film 103 having a double texture structure formed in this way scatters light in the long wavelength region by the first unevenness 104 having a long unevenness period, and short wavelength region by the second unevenness 105 having a short unevenness period. It becomes possible to scatter light.

  In the method for manufacturing the substrate for a thin film photoelectric conversion device according to the second embodiment described above, the ion beam 106 is made perpendicular to the substrate surface of the translucent insulating substrate 102 on the surface of the first unevenness 104 having a long unevenness period. By performing the scan irradiation, the second unevenness 105 having a short unevenness cycle is selectively formed on the slope of the first unevenness 104. And since the 2nd unevenness | corrugation 105 is hardly formed in the top part and trough part of the 1st unevenness | corrugation 104, the 1st unevenness | corrugation 104 with a long unevenness | corrugation period does not lose | disappear at the time of formation of the 2nd unevenness | corrugation 105, Moreover, the 2nd unevenness | corrugation 105 can be formed with a desired uneven | corrugated period. As a result, a double texture structure with good light scattering characteristics can be reliably formed on the surface of the transparent electrode film 103.

  Moreover, in the manufacturing method of the substrate for a thin film photoelectric conversion device according to the second embodiment, since the first unevenness 104 is formed by the chemical etching method, the inclination of the recessed portion of the first unevenness 104 becomes gentle, and the first The generation of steep valleys on the surface of the unevenness 104 is suppressed. Therefore, when the photoelectric conversion device is formed by forming a photoelectric conversion layer such as a microcrystalline silicon film over the thin film photoelectric conversion device substrate 101 manufactured by the manufacturing method of this embodiment, the valleys of the first unevenness 104 There is no defect on the top, and a photoelectric conversion device with high power generation efficiency can be obtained.

  Moreover, in the manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses concerning Embodiment 2, since the film forming process at the time of formation of the transparent electrode film 3 is 1 time, a manufacturing method is simple.

  Therefore, according to the manufacturing method of the substrate for a thin film photoelectric conversion device according to the second embodiment, the thin film photoelectric conversion device capable of suppressing the generation of defects in the photoelectric conversion layer formed in the upper layer and improving the photoelectric conversion efficiency of the thin film photoelectric conversion device. There exists an effect that the board | substrate for converters is obtained.

Embodiment 3 FIG.
FIG. 8: is a principal part which shows typically schematic structure of the photoelectric conversion apparatus 201 produced using the board | substrate 1 for thin film photoelectric conversion apparatuses manufactured by the manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses concerning Embodiment 1. FIG. It is sectional drawing. The photoelectric conversion device 201 includes an amorphous silicon (Si) photoelectric conversion layer 14, an intermediate layer 15, microcrystalline silicon on a thin film photoelectric conversion device substrate 1 including a translucent insulating substrate 2 and a transparent electrode film 3. (Si) It has the structure by which the photoelectric converting layer 16 and the back surface electrode layer 17 were laminated | stacked in order. In addition, an undercoat layer 18 made of silicon oxide may be provided between the translucent insulating substrate 2 and the transparent electrode film 3 as an impurity blocking layer as necessary.

  The amorphous silicon (Si) photoelectric conversion layer 14 includes a p-type amorphous Si layer 141, an i-type amorphous Si layer 142, and an n-type amorphous Si layer 143 stacked from the transparent electrode film 3 side. -I-n junction. The microcrystalline silicon (Si) photoelectric conversion layer 16 includes a p-i-n junction in which a p-type microcrystalline Si layer 161, an i-type microcrystalline Si layer 162, and an n-type microcrystalline Si layer 163 are stacked from the intermediate layer 15 side. Have

Note that although the amorphous silicon (Si) photoelectric conversion layer 14 and the microcrystalline silicon (Si) photoelectric conversion layer 16 are stacked as the photoelectric conversion layer, only one of these layers may be used. Layers may be stacked. Further, as a material for the photoelectric conversion layer, a mixed material of Si and germanium (Ge), Si and carbon (C), or the like may be used instead of Si. These photoelectric conversion layers can be formed by, for example, a CVD method using a semiconductor source gas such as silane (SiH ₄ ).

  The intermediate layer 15 is provided between the amorphous silicon (Si) photoelectric conversion layer 14 and the microcrystalline silicon (Si) photoelectric conversion layer 16 and uses partially oxidized Si (SiOx), a transparent conductive material, or the like. Can do. The back electrode layer 17 is a second electrode, and a transparent conductive material or a metal material such as silver (Ag) can be used, and can be formed by a CVD method, a sputtering method, or the like.

  A method for manufacturing the photoelectric conversion device 201 configured as described above will be described. First, the thin film photoelectric conversion device substrate 1 is manufactured by the method for manufacturing a thin film photoelectric conversion device substrate according to the first embodiment. Note that an undercoat layer 18 may be provided between the translucent insulating substrate 2 and the transparent electrode film 3 as necessary.

  Next, an amorphous silicon (Si) photoelectric conversion layer 14 is formed on the transparent electrode film 3 by a known method. For example, as the amorphous silicon (Si) photoelectric conversion layer 14, a p-type amorphous Si layer 141, an i-type amorphous Si layer 142, and an n-type amorphous Si layer 143 are formed by CVD from the transparent electrode film 3 side. Sequentially formed.

  Next, the intermediate layer 15 is formed on the amorphous silicon (Si) photoelectric conversion layer 14 by a known method. For example, partially oxidized Si (SiOx) is formed by a CVD method.

  Next, a microcrystalline silicon (Si) photoelectric conversion layer 16 is formed on the intermediate layer 15 by a known method. For example, as the microcrystalline silicon (Si) photoelectric conversion layer 16, a p-type microcrystalline Si layer 161, an i-type microcrystalline Si layer 162, and an n-type microcrystalline Si layer 163 are sequentially formed from the intermediate layer 15 side by a CVD method.

  Next, the back electrode layer 17 is formed on the microcrystalline silicon (Si) photoelectric conversion layer 16 by a known method. For example, a silver (Ag) film is formed as the back electrode layer 17 by a sputtering method. Thus, the photoelectric conversion device 201 according to the third embodiment shown in FIG. 8 is manufactured.

  In the thin film photoelectric conversion device manufacturing method according to the third embodiment described above, the thin film photoelectric conversion device substrate 1 manufactured by the thin film photoelectric conversion device substrate manufacturing method according to the first embodiment is used. The utilization efficiency of light in a wide wavelength range is increased, and a thin film photoelectric conversion device having excellent photoelectric conversion efficiency can be obtained.

  In addition, in order to form the photoelectric conversion device 201 by forming the photoelectric conversion layer 16 on the thin film photoelectric conversion device substrate 1 manufactured by the manufacturing method of the present embodiment, the concave-convex period formed on the surface of the transparent electrode film 3. Even in the valleys of the long first irregularities 4, no defects occur in the photoelectric conversion layer 16, and a thin film photoelectric conversion device with high photoelectric conversion efficiency is obtained.

  In addition, a plurality of thin film photoelectric conversion device cells having the configuration described in the above embodiment are formed on the light-transmitting insulating substrate 2, and the adjacent thin film photoelectric conversion device cells are electrically connected to each other to thereby perform photoelectric conversion. An efficient thin film photoelectric conversion module can be realized. In this case, what is necessary is just to electrically connect one transparent electrode film 3 and the other back surface electrode layer 17 of an adjacent thin film photoelectric conversion cell.

  As described above, the method for manufacturing a substrate for a thin film photoelectric conversion device according to the present invention is useful for manufacturing a substrate for a high performance thin film photoelectric conversion device.

DESCRIPTION OF SYMBOLS 1 Substrate for thin film photoelectric conversion devices 2 Translucent insulating substrate 3 Transparent electrode film 4 First unevenness 5 Second unevenness 6 Pulsed laser light 14 Photoelectric conversion layer 15 Intermediate layer 16 Photoelectric conversion layer 17 Back electrode layer 18 Undercoat layer DESCRIPTION OF SYMBOLS 101 Substrate for thin film photoelectric conversion device 102 Translucent insulating substrate 103 Transparent electrode film 104 First unevenness 105 Second unevenness 106 Ion beam 141 p-type amorphous Si layer 142 i-type amorphous Si layer 143 n-type non Crystalline Si layer 161 p-type microcrystalline Si layer 162 i-type microcrystalline Si layer 163 n-type microcrystalline Si layer 201 Photoelectric conversion device

Claims (11)

A first step of forming an electrode film on the substrate;
A second step of forming first irregularities on the surface of the electrode film;
A third step of forming a second concavo-convex having a concavo-convex period shorter than the first concavo-convex on the slope of the first concavo-convex by irradiating the surface of the first concavo-convex with an energy beam;
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses characterized by including. The energy beam is a pulsed laser beam;
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses of Claim 1 characterized by these. The wavelength of the pulse laser beam is in the range of 200 nm to 1000 nm;
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses of Claim 2 characterized by these. The light source of the pulse laser beam is at least one selected from a fundamental wave of an Nd: YAG laser, a harmonic wave of an Nd: YAG laser, an excimer laser, and an ultraviolet laser;
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses of Claim 2 characterized by these. The light source of the pulse laser beam is an excimer laser;
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses of Claim 4 characterized by these. The energy beam is an ion beam;
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses of Claim 1 characterized by these. The ion beam is a rare gas ion beam;
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses of Claim 6 characterized by these. In the first step, a zinc oxide film or an indium tin oxide film is formed as the electrode film by a sputtering method,
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses as described in any one of Claims 1-7 characterized by these. In the second step, the first irregularities are formed on the surface of the electrode film by chemical etching using an acidic solution.
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses as described in any one of Claims 1-8 characterized by these. In the first step, a tin oxide film is formed as the electrode film by a thermal CVD method,
The first unevenness is formed when the electrode film is formed;
The manufacturing method of the board | substrate for thin film photoelectric conversion apparatuses as described in any one of Claims 1-7 characterized by these. A first electrode forming step of forming a first electrode having translucency on a translucent insulating substrate by the method for manufacturing a substrate for a thin film photoelectric conversion device according to any one of claims 1 to 10,
A photoelectric conversion layer forming step of forming a photoelectric conversion layer for performing photoelectric conversion on the first electrode;
A second electrode forming step of forming a second electrode on the photoelectric conversion layer;
The manufacturing method of the thin film photoelectric conversion apparatus characterized by including.

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