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Publication numberUS20060213550 A1
Publication typeApplication
Application numberUS 11/422,570
Publication date28 Sep 2006
Filing date6 Jun 2006
Priority date27 Mar 1995
Also published asUS7075002
Publication number11422570, 422570, US 2006/0213550 A1, US 2006/213550 A1, US 20060213550 A1, US 20060213550A1, US 2006213550 A1, US 2006213550A1, US-A1-20060213550, US-A1-2006213550, US2006/0213550A1, US2006/213550A1, US20060213550 A1, US20060213550A1, US2006213550 A1, US2006213550A1
InventorsShunpei Yamazaki, Yasuyuki Arai
Original AssigneeSemiconductor Energy Laboratory Co., Ltd.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Thin-film photoelectric conversion device and a method of manufacturing the same
US 20060213550 A1
Abstract
A method of manufacturing a thin-film solar cell, comprising the steps of: forming an amorphous silicon film on a substrate; placing a metal element that accelerates the crystallization of silicon in contact with the surface of the amorphous silicon film; subjecting the amorphous silicon film to a heat treatment to obtain a crystalline silicon film; depositing a silicon film to which phosphorus has been added in contact with the crystalline silicon film; and subjecting the crystalline silicon film and the silicon film to which phosphorus has been added to a heat treatment to getter the metal element from the crystalline film.
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Claims(33)
1. A thin-film device comprising:
a semiconductor film formed over a substrate; and
an n-type semiconductor film formed over the semiconductor film, wherein the n-type semiconductor film contains a metal element.
2. A thin-film device according to claim 1, wherein the semiconductor film comprises a crystalline silicon.
3. A thin-film device according to claim 1, further comprising silicon oxide between the substrate and the semiconductor film.
4. A thin-film device according to claim 1, wherein the metal element comprises at least one selected from the group consisting of nickel, iron, cobalt and platinum.
5. A thin-film device according to claim 1, wherein the thin-film device is a solar cell.
6. A thin-film device comprising:
a semiconductor film formed over a substrate, wherein the semiconductor film contains a metal element at a concentration not higher than 51018 atoms/cm3; and
an n-type semiconductor film formed over the semiconductor film, wherein the n-type semiconductor film contains the metal element.
7. A thin-film device according to claim 6, wherein the semiconductor film comprises a crystalline silicon.
8. A thin-film device according to claim 6, further comprising silicon oxide between the substrate and the semiconductor film.
9. A thin-film device according to claim 6, wherein the metal element comprises at least one selected from the group consisting of nickel, iron, cobalt and platinum.
10. A thin-film device according to claim 6, wherein the thin-film device is a solar cell.
11. A thin-film device comprising:
a semiconductor film formed over a substrate; and
an n-type semiconductor film formed over the semiconductor film, wherein the n-type semiconductor film contains phosphorus and a metal element.
12. A thin-film device according to claim 11, wherein the semiconductor film comprises a crystalline silicon.
13. A thin-film device according to claim 11, further comprising silicon oxide between the substrate and the semiconductor film.
14. A thin-film device according to claim 11, wherein the metal element comprises at least one selected from the group consisting of nickel, iron, cobalt and platinum.
15. A thin-film device according to claim 11, wherein the thin-film device is a solar cell.
16. A thin-film device comprising:
a semiconductor film formed over a substrate;
an n-type semiconductor film formed over the semiconductor film, wherein the n-type semiconductor film contains a metal element; and
a transparent electrode formed over the n-type semiconductor film.
17. A thin-film device according to claim 16, wherein the semiconductor film comprises a crystalline silicon.
18. A thin-film device according to claim 16, further comprising silicon oxide between the substrate and the semiconductor film.
19. A thin-film device according to claim 16, wherein the metal element comprises at least one selected from the group consisting of nickel, iron, cobalt and platinum.
20. A thin-film device according to claim 16, wherein the transparent electrode comprises indium tin oxide.
21. A thin-film device according to claim 16, wherein the thin-film device is a solar cell.
22. A thin-film device comprising:
a semiconductor film formed over a substrate, wherein the semiconductor film contains a metal element at a concentration not higher than 51018 atoms/cm3;
an n-type semiconductor film formed over the semiconductor film, wherein the n-type semiconductor film contains the metal element; and
a transparent electrode formed over the n-type semiconductor film.
23. A thin-film device according to claim 22, wherein the semiconductor film comprises a crystalline silicon.
24. A thin-film device according to claim 22, further comprising silicon oxide between the substrate and the semiconductor film.
25. A thin-film device according to claim 22, wherein the metal element comprises at least one selected from the group consisting of nickel, iron, cobalt and platinum.
26. A thin-film device according to claim 22, wherein the transparent electrode comprises indium tin oxide.
27. A thin-film device according to claim 22, wherein the thin-film device is a solar cell.
28. A thin-film device comprising:
a semiconductor film formed over a substrate;
an n-type semiconductor film formed over the semiconductor film, wherein the n-type semiconductor film contains phosphorus and a metal element; and
a transparent electrode formed over the n-type semiconductor film.
29. A thin-film device according to claim 28, wherein the semiconductor film comprises a crystalline silicon.
30. A thin-film device according to claim 28, further comprising silicon oxide between the substrate and the semiconductor film.
31. A thin-film device according to claim 28, wherein the metal element comprises at least one selected from the group consisting of nickel, iron, cobalt and platinum.
32. A thin-film device according to claim 28, wherein the transparent electrode comprises indium tin oxide.
33. A thin-film device according to claim 28, wherein the thin-film device is a solar cell.
Description
    BACKGROUND OF THE INVENTION
  • [0001]
    1. Field of the Invention
  • [0002]
    The present invention relates to a thin-film photoelectric conversion device, especially a solar cell which is formed on a substrate, and more particularly to a thin-film solar cell having a photoelectric conversion layer formed of a crystalline silicon film.
  • [0003]
    2. Description of the Related Art
  • [0004]
    A solar cell or a solar battery can be manufactured using a variety of semiconductor materials or organic compound materials. However, from an industrial viewpoint, silicon is mainly used for the solar cell. The solar cells using silicon can be classified into a bulk solar cell using a wafer of monocrystal silicon or polycrystal silicon and a thin-film solar cell having a silicon film formed on a substrate. Reduction of manufacturing costs is required, and the thin-film solar cell is expected to have the effect of reducing the costs because less raw materials are used for the thin-film solar cell than for the bulk solar cell.
  • [0005]
    In the field of thin-film solar cells, an amorphous silicon solar cell has been placed into practical use. However, since the amorphous silicon solar cell is lower in conversion efficiency compared with the monocrystal silicon or polycrystal silicon solar cell and also suffers from problems such as deterioration due to light exposure and so on, the use thereof is limited. For that reason, as another means, a thin-film solar cell using a crystalline silicon film has been also developed.
  • [0006]
    A melt recrystallization method and a solid-phase growth method are used for obtaining a crystalline silicon film in the thin-film solar cell. In both the methods an amorphous silicon layer is formed on a substrate and recrystallized, thereby obtaining a crystalline silicon film. In any event, the substrate is required to withstand the crystallization temperature, whereby usable materials are limited. In particular, in the melt recrystallization method, the substrate has been limited to a material that withstands 1,412 C., which is the melting point of silicon.
  • [0007]
    The solid-phase growth method is a method in which an amorphous silicon film is formed on the substrate and crystallized thereafter through a heat treatment. In such a solid-phase growth method, in general, as the temperature becomes high, the processing time may be shortened more. However, the amorphous silicon film is hardly crystallized at a temperature of 500 C. or lower. For example, when the amorphous silicon film which has been grown through a gas-phase growth method is heated at 600 C. so as to be crystallized, 10 hours are required. Also, when the heat treatment is conducted at the temperature of 550 C., 100 hours or longer is required for the heat treatment.
  • [0008]
    For the above reason, a high heat resistance has been required for the substrate of the thin-film solar cell. Therefore, glass, carbon, or ceramic was used for the substrate. However, from the viewpoint of reducing the costs of the solar cell, those substrates are not always proper, and it has been desired that the solar cell be fabricated on a substrate which is most generally used and inexpensive. However, for example, the #7059 glass substrate made by Corning, which is generally used, has a strain point of 593 C., and the conventional crystallization technique allows the substrate to be strained and largely deformed. For that reason, such a substrate could not be used. Also, since a substrate made of a material essentially different from silicon is used, monocrystal cannot be obtained even through crystallization is conducted on the amorphous silicon film through the above means, and silicon having large crystal grains is hard to obtain. Consequently, this causes a limit to an improvement in the efficiency of the solar cell.
  • [0009]
    In order to solve the above problems, a method of crystallizing an amorphous silicon film through a heat treatment is disclosed in U.S. Pat. No. 5,403,772. According to the method disclosed in this patent, in order to accelerate crystallization at a low temperature, a small amount of a metal element is added to the amorphous silicon film as a catalyst material. Further, it is therein disclosed that a lowering of the heat treatment temperature and a reduction of the treatment time are enabled. Also, it is disclosed therein that a simple elemental metal substance, e.g. nickel (Ni), iron (Fe), cobalt (Co), or platinum (Pt), or a compound of any one of those metals and silicon, or the like is suitable for the catalyst material.
  • [0010]
    However, since the catalyst materials used for accelerating crystallization are naturally undesirable for crystalline silicon, it has been desired that the concentration of the catalyst material is as low as possible. The concentration of catalyst material necessary for accelerating crystallization was 11017/cm3 to 11020/cm3. However, even when the concentration is relatively low, since the above catalyst materials are heavy metal elements, the material contained in silicon forms a defect level, thereby lowering the characteristics of a fabricated element.
  • [0011]
    The principle of operation of a solar cell containing a p-n junction can be roughly described as follows. The solar cell absorbs light and generates electron/hole charge pairs due to absorbed light energy. The electrons move toward the n-layer side of the junction, and the holes move toward the p-layer side due to drift caused by the junction electric field and diffusion. However, when the defect levels are high in silicon, the charges are trapped by the defect levels while they are moving in the silicon, thereby disappearing. In other words, the photoelectric conversion characteristics are lowered. The period of time from when the electrons/holes are generated until they disappear is called the “life time”. In the solar cell, it is desirable that the lifetime is long. Hence, it has been necessary to reduce as much as possible the heavy metal elements that generate the defect levels in silicon.
  • SUMMARY OF THE INVENTION
  • [0012]
    The present invention has been made in view of the above circumstances, and therefore an object of the present invention is to provide a method of manufacturing a thin-film solar cell, which retains the feature of crystallization due to the above catalyst material and removes the catalyst material after the crystallization has been completed.
  • [0013]
    Another object of the present invention is to provide a solar cell which has an excellent photoelectric conversion characteristic, using the above method.
  • [0014]
    In accordance with the primary feature of the present invention, a method of manufacturing a photoelectric conversion device includes a step of forming a gettering layer on a crystallized semiconductor layer obtained by using a catalyst metal such as nickel. The gettering layer may be either insulative or semiconductive and contains phosphorus to absorb the catalyst metal such as nickel from the semiconductor layer after it is crystallized, thereby reducing the concentration of the catalyst metal in the semiconductor layer. Specifically, the method includes the steps of:
      • disposing a metal containing layer in contact with an upper or lower surface of a non-single crystalline silicon semiconductor layer;
      • crystallizing the non-single crystalline silicon semiconductor layer by heating, wherein the metal functions to promote the crystallization;
      • forming a gettering layer on or within said semiconductor layer after crystallized, the gettering layer containing phosphorus; and
      • heating said semiconductor layer and the gettering layer in order to getter the metal contained in the semiconductor layer.
  • [0019]
    As the metal element, it is possible to use one or more elements chosen from Ni, Fe, Co, Ru, Rh, Pd, Os, Ir, Pt, Cu, and Au.
  • [0020]
    In accordance with a preferred embodiment of the invention, the gettering layer may be a silicon layer to which phosphorus is added during the deposition thereof onto the crystallized semiconductor layer. In an alternative, the gettering layer may be a phosphorus doped region formed within the crystallized semiconductor layer, namely, a method of the present invention includes a step of introducing phosphorus ions into a surface region of the crystallized semiconductor layer by ion doping after crystallizing the semiconductor layer by the use of the catalyst metal. In a further alternative, the gettering layer may be a phospho-silicate glass (PSG) layer deposited on the crystallized semiconductor layer.
  • [0021]
    In accordance with another aspect of the invention, the catalyst metal is provided by disposing the metal containing layer in contact with an upper or lower surface of a non-single crystalline semiconductor layer to be crystallized. In the case of disposing the metal containing layer under the non-single crystalline semiconductor layer, the metal containing layer may be used also as a lower electrode of the photoelectric conversion device.
  • [0022]
    In accordance with still another aspect of the invention, a solar cell comprises a substrate, a first crystalline silicon film having conductivity type formed on the substrate, and a second crystalline silicon film having another conductivity type adjacent to the first crystalline silicon film, wherein the first crystalline silicon film contains a catalyst element for promoting crystallization of silicon at a concentration not higher than 51018 atoms/cm3. The concentration value disclosed in the present invention is determined by secondary ion mass spectroscopy and corresponds to a maximum value of the measured values.
  • [0023]
    In accordance with a further aspect of the invention, in the above mentioned solar cell, the concentration of the catalyst contained in the second crystalline silicon film is higher than the concentration of the catalyst contained in the first crystalline silicon film.
  • [0024]
    In accordance with a still further aspect of the invention, the crystalline semiconductor film obtained by using the catalyst metal such as nickel has a plurality of crystal grains in the form of needles.
  • [0025]
    According to the present invention, the lifetime of carriers in the crystalline silicon film is increased, and the excellent characteristics of the thin-film solar cell are obtained.
  • BRIEF DESCRIPTION OF THE DRAWINGS
  • [0026]
    The above and other objects and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings.
  • [0027]
    FIGS. 1A to 1D are schematic diagrams showing a method of manufacturing a thin-film solar cell in accordance with the present invention;
  • [0028]
    FIGS. 2A to 2D are schematic diagrams showing a method of manufacturing a thin-film solar cell in accordance with the present invention;
  • [0029]
    FIG. 3 is a diagram showing an example of a cross-sectional structure of a thin-film solar cell in accordance with the present invention; and
  • [0030]
    FIG. 4 is a diagram showing an example of a cross-sectional structure of a thin-film solar cell in accordance with the present invention.
  • DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • [0031]
    Now, a description will be given in more detail of embodiments of the present invention with reference to the accompanying drawings.
  • First Embodiment
  • [0032]
    The first embodiment shows a process of manufacturing a thin-film solar cell through a method of forming an amorphous silicon film in close contact with a metal element that accelerates the crystallization of silicon, crystallizing said amorphous silicon film through a heat treatment, and removing said metal element remaining in the amorphous silicon film after the crystallization.
  • [0033]
    This embodiment will be described with reference to FIGS. 1A to 1D. In this embodiment, nickel is used as a metal element having a catalyst action that accelerates the crystallization of silicon. First, a silicon oxide film 102 having a thickness of 0.3 μm is formed on a glass substrate (for example, Corning 7059 glass substrate) 101 as an underlying layer. The silicon oxide film 102 is formed through a plasma CVD technique using tetra ethoxy silane (TEOS as a raw material), and also can be formed through a sputtering technique as another method. Subsequently, an amorphous silicon film 103 is formed using silane gas as a raw material through a plasma CVD technique. The formation of the amorphous silicon film 103 may be conducted using a low pressure thermal CVD technique, a sputtering technique, or an evaporation method. The above amorphous silicon film 103 may be a substantially-intrinsic amorphous silicon film or may contain boron (B) at 0.001 to 0.1 atms %. Also, the thickness of the amorphous silicon film 103 is set at 10 μm. However, the thickness may be set at a required value (FIG. 1A).
  • [0034]
    Subsequently, the substrate is immersed in an ammonium hydroxide, hydrogen peroxide mixture and then held at 70 C. for 5 minutes, to thereby form an oxide film (not shown) on the surface of the amorphous silicon film 103. The silicon oxide film is formed in order to improve wettability in the next step process of coating with a nickel acetate solution. The nickel acetate solution is coated on the surface of the amorphous silicon film 103 by spin coating. The nickel functions as an element that accelerates the crystallization of the amorphous silicon film 103.
  • [0035]
    Subsequently, the amorphous silicon film 103 is held at a temperature of 450 C. for one hour in a nitrogen atmosphere, thereby eliminating hydrogen from the amorphous silicon film 103. This is because dangling bonds are intentionally produced in the amorphous silicon film, to thereby lower the threshold energy in subsequent crystallizing. Then, the amorphous silicon film 103 is subjected to a heat treatment at 550 C. for 4 to 8 hours in the nitrogen atmosphere, to thereby crystallize the amorphous silicon film 103. The temperature during crystallizing can be set to 550 C. because of the action of the nickel. 0.001 atms % to 5 atms % hydrogen is contained in crystallized silicon film 104. During the above heat treatment, nickel accelerates the crystallization of the silicon film while it is moving in the silicon film.
  • [0036]
    In this way, the crystalline silicon film 104 is formed on the glass substrate. Subsequently, a phospho-silicate glass (PSG) 105 is formed on the crystalline silicon film 104. The phospho-silicate glass (PSG) 105 is formed, using a gas mixture consisting of silane, phosphine, and oxygen, at a temperature of 450 C. through an atmospheric CVD technique. The concentration of phosphorus in the phospho-silicate glass is set to 1 to 30 wt %, preferably 7 wt %. The phospho-silicate glass (PSG) 105 is used to getter nickel remaining in the crystalline silicon film. Even though the phospho-silicate glass 105 is formed at only 450 C., its effect is obtained. More effectively, the phospho-silicate glass 105 may be subjected to a heat treatment at a temperature of 500 to 800 C., preferably 550 C. for 1 to 4 hours in a nitrogen atmosphere. As another method, the phospho-silicate glass 105 can be replaced by a silicon film to which phosphorus of 0.1 to 10 wt % has been added with the same effect (FIG. 1B).
  • [0037]
    Thereafter, the phospho-silicate glass 105 is etched using an aqueous hydrogen fluoride solution so as to be removed from the surface of the crystalline silicon film 104. As a result, the surface of the crystalline silicon film 104 is exposed. On that surface there is formed an n-type crystalline silicon film 106. The n-type crystalline silicon film 106 may be formed through a plasma CVD technique or through a low pressure thermal CVD technique. The n-type crystalline silicon film 106 is desirably formed at a thickness of 0.02 to 0.2 μm, and in this embodiment, it is formed at a thickness of 0.1 μm (FIG. 1C).
  • [0038]
    Then, a transparent electrode 107 is formed through a sputtering technique on the above n-type crystalline silicon film 106. The transparent electrode 107 is made of indium tin oxide alloy (ITO) and has a thickness of 0.08 μm. Finally, a process of providing output electrodes 103 is conducted. In providing the output electrodes 108, as shown in FIG. 1D, a negative side electrode is disposed on the transparent electrode 107, and a positive side electrode is disposed on the crystalline silicon film 104 by removing parts of the transparent electrode 107, the n-type crystalline silicon film 106, and the crystalline silicon film 104. The output electrodes 108 can be formed by sputtering or vacuum evaporation, or using an aluminum or silver paste or the like. Furthermore, after the provision of the output electrodes 108, the product is subjected to a heat treatment at 150 C. to 300 C. for several minutes with the result that the adhesion between the output electrodes 108 and the underlying layer becomes high, thereby obtaining an excellent electric characteristic. In this embodiment, the product is subjected to a heat treatment at 200 C. for 30 minutes in a nitrogen atmosphere using an oven.
  • [0039]
    Through the above-mentioned processes, a thin-film solar cell is completed.
  • Second Embodiment
  • [0040]
    In a second embodiment, there is described a thin-film solar cell which is formed in a process where a metal element that accelerates the crystallization of crystalline silicon is removed after crystallization, through a method where phosphorus is implanted into the surface of the crystalline silicon film via a plasma doping method.
  • [0041]
    The second embodiment will be described with reference to FIGS. 2A to 2D. Nickel is used in this embodiment as a metal element functioning as a catalyst to accelerate the crystallization to accellerate the crystallization of silicon. First, a silicon oxide film 202 having a thickness of 0.3 μm is formed on a glass substrate (for example, Corning 7059 glass substrate) 201 as an underlying layer. The silicon oxide film 202 is formed by plasma CVD with tetra ethoxy silane (TEOS as a raw material), and also can be formed through a sputtering technique as another method. Subsequently, an amorphous silicon film 203 is formed with silane gas as a raw material through a plasma CVD technique. The formation of the amorphous silicon film 203 may be conducted using a low pressure thermal CVD technique, a sputtering technique, or an evaporation method. The above amorphous silicon film 203 may be a substantially-intrinsic amorphous silicon film or an amorphous silicon film to which boron (B) of 0.001 to 0.1 atms % has been added. Also, the thickness of the amorphous silicon film 203 is set at 20 μm. However, the thickness may be set at any required value (FIG. 2A).
  • [0042]
    Thereafter, the substrate is immersed in an ammonium hydroxide, hydrogen peroxide mixture at 70 C. for 5 minutes, to thereby form an oxide film (not shown) on the surface of the amorphous silicon film 203. The silicon oxide film is formed in order to improve wettability in the next step of coating with a nickel acetate solution. The nickel acetate solution is coated on the surface of the amorphous silicon film 203 by spin coating. The nickel element functions as an element that accelerates the crystallization of the amorphous silicon film 203.
  • [0043]
    Subsequently, the amorphous silicon film 203 is held at a temperature of 450 C. for one hour in a nitrogen atmosphere, thereby eliminating hydrogen from the amorphous silicon film 203. This is because dangling bonds are intentionally produced in the amorphous silicon film, to thereby lower the threshold energy in subsequent crystallizing. Then, the amorphous silicon film 203 is subjected to a heat treatment at 550 C. for 4 to 8 hours in a nitrogen atmosphere, to thereby crystallize the amorphous silicon film 203. The temperature during crystallizing can be set to 550 C. because of the action of the nickel. 0.001 atms % to 5 atms % hydrogen is contained in a crystallized silicon film 204. During the above heat treatment, nickel accelerates the crystallization of the silicon film 204 while it is moving in the silicon film.
  • [0044]
    In this way, the crystalline silicon film 204 can be formed on the glass substrate. In this state, the implantation of phosphorus (P) ions is conducted by a plasma doping method. The dose amount may be set to 11014 to 11017/cm2, and in this embodiment, it is set to 11016/cm2. The accelerating voltage is set to 20 keV. Through this process, a layer containing phosphorus at a high concentration is formed within a region of 0.1 to 0.2 μm depthwise from the surface of the crystalline silicon film 204. Thereafter, a heat treatment is conducted on the crystalline silicon film 204 in order to getter nickel remaining in the crystalline silicon film 204. The crystalline silicon film 204 may be subjected to a heat treatment at 500 to 800 C., preferably 550 C. for 1 to 4 hours in a nitrogen atmosphere (FIG. 2B).
  • [0045]
    In the crystalline silicon film 204, since the region into which phosphorus ions have been implanted has its crystallinity destroyed, it becomes of a substantially amorphous structure immediately after the ions have been implanted thereinto. Thereafter, since that region is crystallized through said heat treatment, it is usable as the n-type layer of the solar cell even in this state. In this case, the concentration of nickel in the i-type or p-type layer 204 is lower than in the phosphorus doped n-type layer.
  • [0046]
    In accordance with a preferred embodiment of the invention, the phosphorus implanted region is more desirably removed since nickel that has functioned as a catalyst element is segregated in this region. As the removing method, after a thin natural oxide film on the surface has been etched using an aqueous hydrogen fluoride aqueous solution, it is removed via dry etching using sulfur hexafluoride and nitric trifluoride. With this process, the surface of the crystalline silicon film 204 is exposed. An n-type crystalline silicon film 205 is formed on that surface. The n-type crystalline silicon film 205 may be formed by plasma CVD or low pressure thermal CVD. The n-type crystalline silicon film 205 is desirably formed at a thickness of 0.02 to 0.2 μm, and in this embodiment, it is formed at a thickness of 0.1 μm (FIG. 2C).
  • [0047]
    Then, a transparent electrode 206 is formed via a sputtering technique on the above n-type crystalline silicon film 205. The transparent electrode 206 is made of indium tin oxide alloy (ITO) and has a thickness of 0.08 μm. Finally, a process of providing output lead electrodes 207 is conducted. In providing the output electrodes 207, as shown in FIG. 2D, a negative side electrode is disposed on the transparent electrode 206, and a positive side electrode is disposed on the crystalline silicon film 204 by removing parts of the transparent electrode 206, the n-type crystalline silicon film 205, and the crystalline silicon film 204. The output electrodes 207 can be formed through a sputtering technique or an evaporation method, or by using aluminum or silver paste or the like. Furthermore, after the provision of the output lead electrodes 207, the substrate is subjected to a heat treatment at 150 C. to 300 C. for several minutes with the result that the adhesion between the output electrodes 207 and the underlying layer becomes high, thereby obtaining excellent electric characteristics. In this embodiment, the substrate is subjected to a heat treatment at 200 C. for 30 minutes in a nitrogen atmosphere using an oven.
  • [0048]
    Through the above-mentioned processes, a thin-film solar cell is completed.
  • Third Embodiment
  • [0049]
    A third embodiment shows an example where in the process of manufacturing the thin-film solar cell described with reference to the first and second embodiments, the surface of the crystalline silicon film is subjected to an anisotropic etching process so as to make the surface of the solar cell irregular as shown in FIG. 3. A technique by which that surface is made irregular so that reflection from the surface of the solar cell is reduced is called a “texture technique”.
  • [0050]
    A silicon oxide film 302 having a thickness of 0.3 μm is formed on a glass substrate (for example, Corning 7059 glass substrate) 301 as an underlying layer. The silicon oxide film 302 is formed by plasma CVD with tetra ethoxy silane (TEOS as a raw material), and also can be formed by sputtering as another method. Subsequently, an amorphous silicon film is formed by plasma CVD. The formation of the amorphous silicon film may be conducted by low pressure thermal CVD, sputtering, evaporation, or the like. The above amorphous silicon film 303 may be a substantially-intrinsic amorphous silicon film or an amorphous silicon film to which of 0.001 to 0.1 atms % boron (B) has been added. Also, the thickness of the amorphous silicon film is set at 20 μm. However, the thickness may be set at any required value.
  • [0051]
    Subsequently, the substrate is immersed in an ammonium hydroxide and hydrogen peroxide mixture and then held at 70 C. for 5 minutes, to thereby form an oxide film on the surface of the amorphous silicon film. The silicon oxide film is formed in order to improve wettability in the next step of coating nickel acetate solution. The nickel acetate solution is coated on the surface of the amorphous silicon film by spin coating. The nickel functions as an element that accelerates the crystallization of the amorphous silicon film.
  • [0052]
    Subsequently, the amorphous silicon film is held at a temperature of 450 C. for one hour in a nitrogen atmosphere, thereby eliminating hydrogen from the amorphous silicon film. This is because dangling bonds are intentionally produced in the amorphous silicon film, to thereby lower the threshold energy in subsequent crystallizing. Then, the amorphous silicon film is subjected to a heat treatment at 550 C. for 4 to 8 hours in a nitrogen atmosphere, to thereby crystalline the amorphous silicon film to obtain a crystalline silicon film 303. The temperature during crystallizing can be set to 550 C. because of the action of nickel. 0.001 atms % to 5 atms % of hydrogen is contained in the crystalline silicon film 303. During the above heat treatment, nickel accelerates the crystallization of the silicon film 303 while it is moving in the silicon film.
  • [0053]
    In this way, the crystalline silicon film 303 can be formed on the glass substrate. Then, a gettering process is conducted on the crystalline silicon film 304 in order to remove nickel remaining in the crystalline silicon film 304. A method of conducting the gettering process may include forming a phospho-silicate glass (PSG) on the crystalline silicon film 303, or implanting phosphorus ions into the surface of the crystalline silicon film 303.
  • [0054]
    In the method comprising of forming the phospho-silicate glass (PSG), the phospho-silicate glass film is formed via atomspheric CVD, using a gas mixture consisting of silane, phosphine, and oxygen, at a temperature of 450 C. The gettering process is then conducted by subjecting the crystalline silicon film to a heat treatment at 550 C. for 1 to 4 hours in a nitrogen atmosphere. Thereafter, the phospho-silicate glass film is desirably etched using an aqueous hydrogen fluoride aqueous solution so as to be removed.
  • [0055]
    In the method comprising implanting phosphorus ions into the surface of the crystalline silicon film, the implantation of ions can be conducted through plasma doping. The dose amount may be set to 11014 to 11017/cm2, and in this embodiment, it is set to 11016/cm2. The accelerating voltage is set to 20 keV. Through this process, a layer containing phosphorus at a high concentration is formed within a region of 0.1 to 0.2 μm depthwise from the surface of the crystalline silicon film. Thereafter, a heat treatment is conducted on the crystalline silicon film in order to getter nickel remaining in the crystalline silicon film. The heat treatment is conducted at a temperature of 500 to 800 C., preferably 550 C. for 1 to 4 hours in a nitrogen atmosphere.
  • [0056]
    After the gettering process has been completed, a texture process is conducted on the surface of the crystalline silicon film. The texture process can be conducted using hydrazine or sodium hydroxide aqueous solution. Hereinafter, a case of using sodium hydroxide will be described.
  • [0057]
    The texture process is conducted by heating a 2% aqueous solution of sodium hydroxide to 80 C. Under this condition, the etching rate of the crystalline silicon film thus obtained in this embodiment is about 1 μm/min. The etching is conducted for five minutes, and thereafter the crystalline silicon film is immersed in boiling water in order to immediately cease the reaction and then the film is sufficiently cleaned by flowing water. As a result of observing the surface of the crystalline silicon film which has been subjected to the texture process through an electron microscope, an unevenness of about 0.1 to 5 μm is found on the surface although it is at random.
  • [0058]
    An n-type crystalline silicon film 304 is formed on that surface. The n-type crystalline silicon film 304 may be formed through a plasma CVD technique or through a low pressure thermal CVD technique. The n-type crystalline silicon film 304 is desirably formed at a thickness of 0.02 to 0.2 μm, and in this embodiment, it is formed at a thickness of 0.1 μm.
  • [0059]
    Then, a transparent electrode 305 is formed by sputtering on the above n-type crystalline silicon film 304. The transparent electrode 305 is made of indium tin oxide alloy (ITO) and has a thickness of 0.08 μm. Finally, a process of providing output electrodes 307 is conducted. In providing the output electrodes 307, as shown by the structure in FIG. 3D, a negative side electrode is disposed on the transparent electrode 305, and a positive side electrode is disposed on the crystalline silicon film 303 by removing parts of the transparent electrode 305, the n-type crystalline silicon film 304, and the crystalline silicon film 303. The output electrodes 306 can be formed by sputtering or vacuum evaporation, or using an aluminum or silver paste or the like. Furthermore, after the provision of the output lead electrodes 307, the entire structure is subjected to a heat treatment at 150 C. to 300 C. for several minutes with the result that the adhesion between the lead electrodes 207 and the underlying layers becomes high, thereby obtaining excellent electric characteristics. In this embodiment, the heat treatment was conducted at 200 C. for 30 minutes in a nitrogen atmosphere using an oven.
  • [0060]
    Through the above-mentioned processes, a thin-film solar cell having the texture structure on the surface is completed.
  • Fourth Embodiment
  • [0061]
    A fourth embodiment is a process of manufacturing a thin-film solar cell, as shown in FIG. 4, in which a coating of a metal element that accelerates the crystallization of silicon is formed on a substrate, an amorphous silicon film is formed on the coating of metal element, the amorphous silicon film is crystallized through a heat treatment, and after crystallization, the metal element diffused in the silicon film is removed therefrom.
  • [0062]
    First, a coating of the metal element that accelerates the crystallization of silicon is formed on a substrate. Nickel is used as the metal element. A silicon oxide film having a thickness of 0.3 μm is first formed on a glass substrate (for example, Corning 7059 glass substrate) 401 as an underlying layer 402. The silicon oxide film is formed through a plasma CVD technique with of tetra ethoxy silane (TEOS) as a raw material, and also can be formed through a sputtering technique as another method. Subsequently, a nickel film 407 is formed on the substrate. The nickel film 407 having 0.1 μm is formed through an electron beam evaporation method using a tablet made of pure nickel. Then, an amorphous silicon film is formed through a plasma CVD technique. The formation of the amorphous silicon film may be conducted through low pressure thermal CVD, sputtering, evaporation, or the like. The above amorphous silicon film may be a substantially-intrinsic amorphous silicon film or an amorphous silicon film to which 0.001 to 0.1 atms % boron (B) has been added. Also, the thickness of the amorphous silicon film is set at 10 μm. However, the thickness may be set at any required value.
  • [0063]
    Subsequently, the amorphous silicon film is held at a temperature of 450 C. for one hour in a nitrogen atmosphere, thereby eliminating hydrogen from the amorphous silicon film. This is because dangling bonds are intentionally produced in the amorphous silicon film, to thereby lower the threshold energy in subsequent crystallizing. Then, the amorphous silicon film is subjected to a heat treatment at 550 C. for 4 to 8 hours in a nitrogen atmosphere, to thereby crystallize the amorphous silicon film to obtain a crystalline silicon film 403. The temperature during crystallizing can be set to 550 C. because of the action of the nickel. 0.001 atms % hydrogen to 5 atms % is contained in a the crystalline silicon film 403. During the above heat treatment, a small amount of nickel diffuses into the silicon film from the nickel film disposed under the amorphous silicon film, and accelerates the crystallization of the crystalline silicon film 403 while it is moving in the silicon film.
  • [0064]
    In this way, the crystalline silicon film 403 is formed on the glass substrate. Subsequently, a phospho-silicate glass (PSG) is formed on the crystalline silicon film 403. The phospho-silicate glass (PSG) is formed by atmospheric CVD gas, using a mixture consisting of silane, phosphine, and oxygen, at a temperature of 450 C. The concentration of phosphorus in the phospho-silicate glass is set to 1 to 30 wt %, preferably 7 wt %. The phospho-silicate glass is used to getter nickel remaining in the crystalline silicon film. Even though the phospho-silicate glass is formed at only 450 C., its effect is obtained. More effectively, the phospho-silicate glass may be subjected to a heat treatment at a temperature of 500 to 800 C., preferably 550 C. for 1 to 4 hours in the nitrogen atmosphere. As another method, the phospho-silicate glass can be replaced with the same effect by a silicon film to which 0.1 to 10 wt % phosphorus has been added with the same effect.
  • [0065]
    Thereafter, the phospho-silicate class is etched using an aqueous hydrogen fluoride solution so as to be removed from the surface of the crystalline silicon film. As a result, the surface of the crystalline silicon film 403 is exposed. An n-type crystalline silicon film 404 is formed on that surface. The r-type crystalline silicon film 404 may be formed by plasma CVD or low pressure thermal CVD. The n-type crystalline silicon film 404 is desirably formed at a thickness of 0.02 to 0.2 μm, and in this embodiment, it is formed at a thickness of 0.1 μm.
  • [0066]
    Then, a transparent electrode 405 is formed by sputtering on the above n-type crystalline silicon film 404. The transparent electrode 405 is made of indium tin oxide alloy (ITO) and has a thickness of 0.08 μm. Finally, a process of providing output electrodes 406 is conducted. In providing the output electrodes, as shown in FIG. 4, a negative side electrode is disposed on the transparent electrode 405, and a positive side electrode is disposed on the crystalline silicon film 403 by removing parts of the transparent electrode 405, the n-type crystalline silicon film 404 and the crystalline silicon film 403. The output electrodes 406 can be formed by sputtering or vacuum evaporation, or by using aluminum or silver paste or the like. Furthermore, after the provision of the output electrodes, the substrate is subjected to a heat treatment at 150 C. to 300 C., for example at 200 C. for 30 minutes in a nitrogen atmosphere, with the result that the adhesion between the output electrodes and the underlying layer becomes high, thereby obtaining excellent electric characteristics.
  • [0067]
    Through the above-mentioned processes, a thin-film solar cell is completed.
  • [0068]
    As was described above, in the method of manufacturing the thin-film solar cell in accordance with the present invention, in a process of crystallizing an amorphous silicon film by a heat treatment, a catalyst material such as nickel is used, thereby making it possible to obtain a crystalline silicon film at a heat treatment temperature lower than in the conventional methods. Furthermore, the method of the present invention enables the concentration of the catalyst material remaining in the crystalline silicon film obtained to be lowered. As a result, a thin-film solar cell that uses an inexpensive glass substrate and is excellent in photoelectric conversion characteristic can be obtained.
  • [0069]
    The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto, and their equivalents.
Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4038104 *7 Jun 197626 Jul 1977Kabushiki Kaisha Suwa SeikoshaSolar battery
US4124410 *21 Nov 19777 Nov 1978Union Carbide CorporationSilicon solar cells with low-cost substrates
US4389534 *11 Dec 198121 Jun 1983Messerschmitt-Bolkow-Blohm GmbhAmorphous silicon solar cell having improved antireflection coating
US4443652 *9 Nov 198217 Apr 1984Energy Conversion Devices, Inc.Electrically interconnected large area photovoltaic cells and method of producing said cells
US4464823 *3 Aug 198314 Aug 1984Energy Conversion Devices, Inc.Method for eliminating short and latent short circuit current paths in photovoltaic devices
US4561171 *1 Apr 198331 Dec 1985Shell Austria AktiengesellschaftProcess of gettering semiconductor devices
US4571448 *16 Nov 198118 Feb 1986University Of DelawareThin film photovoltaic solar cell and method of making the same
US4781766 *29 May 19871 Nov 1988Astrosystems, Inc.Fault tolerant thin-film photovoltaic cell and method
US5085711 *15 Feb 19904 Feb 1992Sanyo Electric Co., Ltd.Photovoltaic device
US5244819 *22 Oct 199114 Sep 1993Honeywell Inc.Method to getter contamination in semiconductor devices
US5275851 *3 Mar 19934 Jan 1994The Penn State Research FoundationLow temperature crystallization and patterning of amorphous silicon films on electrically insulating substrates
US5328519 *7 May 199112 Jul 1994Canon Kabushiki KaishaSolar cells
US5330918 *31 Aug 199219 Jul 1994The United States Of America As Represented By The Secretary Of The NavyMethod of forming a high voltage silicon-on-sapphire photocell array
US5360748 *22 Jan 19931 Nov 1994Kabushiki Kaisha ToshibaMethod of manufacturing a semiconductor device
US5380372 *8 Oct 199210 Jan 1995Nukem GmbhSolar cell and method for manufacture thereof
US5403772 *3 Dec 19934 Apr 1995Semiconductor Energy Laboratory Co., Ltd.Method for manufacturing semiconductor device
US5426061 *6 Sep 199420 Jun 1995Midwest Research InstituteImpurity gettering in semiconductors
US5426064 *8 Mar 199420 Jun 1995Semiconductor Energy Laboratory Co., Ltd.Method of fabricating a semiconductor device
US5461002 *29 May 199124 Oct 1995Safir; YakovMethod of making diffused doped areas for semiconductor components
US5501989 *21 Mar 199426 Mar 1996Semiconductor Energy Laboratory Co., Ltd.Method of making semiconductor device/circuit having at least partially crystallized semiconductor layer
US5529937 *20 Jul 199425 Jun 1996Semiconductor Energy Laboratory Co., Ltd.Process for fabricating thin film transistor
US5543352 *16 Nov 19946 Aug 1996Semiconductor Energy Laboratory Co., Ltd.Method for manufacturing a semiconductor device using a catalyst
US5563426 *18 Nov 19948 Oct 1996Semiconductor Energy Laboratory Co., Ltd.Thin film transistor
US5569610 *8 Mar 199429 Oct 1996Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing multiple polysilicon TFTs with varying degrees of crystallinity
US5575862 *30 Nov 199419 Nov 1996Canon Kabushiki KaishaPolycrystalline silicon photoelectric conversion device and process for its production
US5580792 *13 Feb 19953 Dec 1996Semiconductor Energy Laboratory Co., Ltd.Method of removing a catalyst substance from the channel region of a TFT after crystallization
US5589694 *28 Mar 199531 Dec 1996Semiconductor Energy Laboratory Co., Ltd.Semiconductor device having a thin film transistor and thin film diode
US5595944 *21 Dec 199421 Jan 1997Semiconductor Energy Laboratory Co., Inc.Transistor and process for fabricating the same
US5604360 *24 May 199418 Feb 1997Semiconductor Energy Laboratory Co., Ltd.Semiconductor device including a plurality of thin film transistors at least some of which have a crystalline silicon film crystal-grown substantially in parallel to the surface of a substrate for the transistor
US5608232 *5 Jun 19954 Mar 1997Semiconductor Energy Laboratory Co., Ltd.Semiconductor, semiconductor device, and method for fabricating the same
US5614426 *23 Aug 199525 Mar 1997Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing semiconductor device having different orientations of crystal channel growth
US5614733 *12 Dec 199425 Mar 1997Semiconductor Energy Laboratory Co., Inc.Semiconductor device having crystalline thin film transistors
US5624851 *8 Mar 199429 Apr 1997Semiconductor Energy Laboratory Co., Ltd.Process of fabricating a semiconductor device in which one portion of an amorphous silicon film is thermally crystallized and another portion is laser crystallized
US5639698 *15 Feb 199417 Jun 1997Semiconductor Energy Laboratory Co., Ltd.Semiconductor, semiconductor device, and method for fabricating the same
US5644156 *12 Apr 19951 Jul 1997Kabushiki Kaisha ToshibaPorous silicon photo-device capable of photoelectric conversion
US5646424 *7 Jun 19958 Jul 1997Semiconductor Energy Laboratory Co., Ltd.Transistor device employing crystallization catalyst
US5677549 *12 May 199514 Oct 1997Semiconductor Energy Laboratory Co., Ltd.Semiconductor device having a plurality of crystalline thin film transistors
US5696003 *16 Dec 19949 Dec 1997Sharp Kabushiki KaishaMethod for fabricating a semiconductor device using a catalyst introduction region
US5696388 *12 Nov 19969 Dec 1997Semiconductor Energy Laboratory Co., Ltd.Thin film transistors for the peripheral circuit portion and the pixel portion
US5700333 *27 Mar 199623 Dec 1997Semiconductor Energy Laboratory Co., Ltd.Thin-film photoelectric conversion device and a method of manufacturing the same
US5741615 *23 Apr 199321 Apr 1998Canon Kabushiki KaishaLight receiving member with non-single-crystal silicon layer containing Cr, Fe, Na, Ni and Mg
US5744822 *24 Jan 199728 Apr 1998Semiconductor Energy Laboratory Co., Ltd.Semiconductor device/circuit having at least partially crystallized semiconductor layer
US5773846 *24 May 199530 Jun 1998Semiconductor Energy Laboratory Co., Ltd.Transistor and process for fabricating the same
US5783468 *10 Apr 199621 Jul 1998Semiconductor Energy Laboratory Co. Ltd.Semiconductor circuit and method of fabricating the same
US5789284 *29 Sep 19954 Aug 1998Semiconductor Energy Laboratory Co., Ltd.Method for fabricating semiconductor thin film
US5821562 *30 May 199513 Oct 1998Sharp Kabushiki KaishaSemiconductor device formed within asymetrically-shaped seed crystal region
US5843225 *7 Jun 19951 Dec 1998Semiconductor Energy Laboratory Co., Ltd.Process for fabricating semiconductor and process for fabricating semiconductor device
US5888857 *10 Jun 199630 Mar 1999Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and method for manufacturing the same
US5897347 *24 Sep 199627 Apr 1999Semiconductor Energy Laboratory Co., Ltd.Semiconductor, semiconductor device, and method for fabricating the same
US5915174 *29 Sep 199522 Jun 1999Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and method for producing the same
US5932893 *3 Feb 19983 Aug 1999Semiconductor Energy Laboratory Co., Ltd.Semiconductor device having doped polycrystalline layer
US5956579 *15 Jul 199721 Sep 1999Semiconductor Energy Laboratory Co., Ltd.Semiconductor, semiconductor device, and method for fabricating the same
US5961743 *19 Aug 19975 Oct 1999Semiconductor Energy Laboratory Co., Ltd.Thin-film photoelectric conversion device and a method of manufacturing the same
US5962871 *5 Nov 19965 Oct 1999Semiconductor Energy Laboratory Co., Ltd.Method for producing semiconductor device
US6060725 *19 Sep 19979 May 2000Semiconductor Energy Laboratory Co., Ltd.Thin film transistor using a semiconductor film
US6066518 *21 Jul 199823 May 2000Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing semiconductor devices using a crystallization promoting material
US6071766 *15 Jul 19986 Jun 2000Semiconductor Energy Laboratory Co., Ltd.Method for fabricating semiconductor thin film
US6084247 *18 Dec 19964 Jul 2000Semiconductor Energy Laboratory Co., Ltd.Semiconductor device having a catalyst enhanced crystallized layer
US6090646 *2 Oct 199718 Jul 2000Semiconductor Energy Laboratory Co., Ltd.Method for producing semiconductor device
US6121076 *4 Aug 199719 Sep 2000Semiconductor Energy Laboratory Co., Ltd.Method for producing semiconductor device
US6133119 *9 Jul 199717 Oct 2000Semiconductor Energy Laboratory Co., Ltd.Photoelectric conversion device and method manufacturing same
US6156628 *17 Jul 19985 Dec 2000Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and method of manufacturing the same
US6162704 *21 Jan 199819 Dec 2000Semiconductor Energy Laboratory Co., Ltd.Method of making semiconductor device
US6177302 *22 Sep 199423 Jan 2001Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing a thin film transistor using multiple sputtering chambers
US6197626 *23 Feb 19986 Mar 2001Semiconductor Energy Laboratory Co.Method for fabricating semiconductor device
US6232205 *21 Jul 199815 May 2001Semiconductor Energy Laboratory Co., Ltd.Method for producing a semiconductor device
US6242290 *13 Jul 19985 Jun 2001Semiconductor Energy Laboratory Co., Ltd.Method of forming a TFT by adding a metal to a silicon film promoting crystallization, forming a mask, forming another silicon layer with group XV elements, and gettering the metal through opening in the mask
US6251712 *12 Sep 199726 Jun 2001Semiconductor Energy Laboratory Co., Ltd.Method of using phosphorous to getter crystallization catalyst in a p-type device
US6261875 *2 Nov 199917 Jul 2001Semiconductor Energy Laboratory Co., Ltd.Transistor and process for fabricating the same
US6300558 *20 Apr 20009 Oct 2001Japan Energy CorporationLattice matched solar cell and method for manufacturing the same
US6303415 *10 Jun 199816 Oct 2001Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and method of fabricating same
US6348368 *14 Oct 199819 Feb 2002Semiconductor Energy Laboratory Co., Ltd.Introducing catalytic and gettering elements with a single mask when manufacturing a thin film semiconductor device
US6355509 *28 Jan 199812 Mar 2002Semiconductor Energy Laboratory Co., Ltd.Removing a crystallization catalyst from a semiconductor film during semiconductor device fabrication
US6368904 *8 May 20009 Apr 2002Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and method of manufacturing the same
US6399454 *13 Jul 19984 Jun 2002Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing a semiconductor film and method of manufacturing a semiconductor device
US6420246 *17 Feb 199816 Jul 2002Semiconductor Energy Laboratory Co., Ltd.Method of gettering a metal element for accelerating crystallization of silicon by phosphorous
US6426276 *9 Nov 200030 Jul 2002Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and method of manufacturing the same
US6432756 *22 Jul 199813 Aug 2002Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and fabricating method thereof
US6436745 *31 Oct 200020 Aug 2002Sharp Kabushiki KaishaMethod of producing a semiconductor device
US6448118 *26 Dec 200010 Sep 2002Semiconductor Energy Laboratory Co., Ltd.Semiconductor film manufacturing with selective introduction of crystallization promoting material
US6458637 *27 Jul 20011 Oct 2002Semiconductor Energy Laboratory Co., Ltd.Thin film semiconductor and method for manufacturing the same, semiconductor device and method for manufacturing the same
US6461943 *6 Nov 20008 Oct 2002Semiconductor Energy Laboratory Co., Ltd.Method of making semiconductor device
US6475840 *1 Apr 19975 Nov 2002Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and method for manufacturing the same
US6479333 *21 Mar 200012 Nov 2002Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing a semiconductor device
US6544826 *22 Nov 20008 Apr 2003Semiconductor Energy Laboratory Co., Ltd.Method for producing semiconductor device
US6548370 *17 Aug 200015 Apr 2003Semiconductor Energy Laboratory Co., Ltd.Method of crystallizing a semiconductor layer by applying laser irradiation that vary in energy to its top and bottom surfaces
US6624049 *12 Oct 199923 Sep 2003Semiconductor Energy Laboratory Co., Ltd.Semiconductor device and method of manufacturing the same
US6664144 *19 Jan 200116 Dec 2003Semiconductor Energy Laboratory Co., Ltd.Method of forming a semiconductor device using a group XV element for gettering by means of infrared light
US6670225 *13 Sep 200230 Dec 2003Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing a semiconductor device
US6777273 *11 May 199917 Aug 2004Semiconductor Energy Laboratory Co., Ltd.Semiconductor display device
US6808968 *14 Feb 200226 Oct 2004Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing a semiconductor device
US6821710 *19 Apr 200023 Nov 2004Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing semiconductor device
US6858480 *17 Jan 200222 Feb 2005Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing semiconductor device
US6962837 *5 Apr 20028 Nov 2005Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing a semiconductor film and method of manufacturing a semiconductor device
US20020006712 *28 Aug 200117 Jan 2002Shunpei YamazakiSemiconductor device and method of fabricating same
US20020115271 *14 Feb 200222 Aug 2002Semiconductor Energy Laboratory Co., Ltd.Method of manufacturing a semiconductor device
USRE38266 *20 Apr 20017 Oct 2003Semiconductor Energy Laboratory Co., Ltd.Method for fabricating semiconductor thin film
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US89940094 Sep 201231 Mar 2015Semiconductor Energy Laboratory Co., Ltd.Photoelectric conversion device
US20090139558 *19 Nov 20084 Jun 2009Shunpei YamazakiPhotoelectric conversion device and manufacturing method thereof
US20090165854 *23 Dec 20082 Jul 2009Semiconductor Energy Laboratory Co., Ltd.Photoelectric conversion device and manufacturing method thereof
US20160126395 *3 Nov 20145 May 2016First Solar, Inc.Photovoltaic devices and method of manufacturing
US20160126396 *22 Jan 20155 May 2016First Solar, Inc.Photovoltaic devices and method of manufacturing
CN104051563A *14 Mar 201317 Sep 2014北京北方微电子基地设备工艺研究中心有限责任公司Preparation method of solar cell
Classifications
U.S. Classification136/252
International ClassificationH01L31/068, H01L31/18, H01L31/00
Cooperative ClassificationH01L31/022441, H01L31/0682, H01L31/02363, Y02P70/521, Y02E10/547, H01L31/1804, H01L31/186, H01L31/1872
European ClassificationH01L31/18C, H01L31/18G, H01L31/068, H01L31/18G4
Legal Events
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Owner name: SEMICONDUCTOR ENERGY LABORATORY CO., LTD., JAPAN
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Effective date: 19960319