JPH10233367A - Method and apparatus for forming non-single crystalline semiconductor thin film, and manufacturing method of photovoltaic element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for forming a non-single crystalline semiconductor thin film which can have a high photovoltaic conversion efficiency over a large area on a substrate, with high quality, excellent uniformity, high reproducibility and less defects, and also can be manufactured on a mass-production basis. SOLUTION: In the fabricating apparatus and the method, a deposition chamber 102 has a film formation space defined by a wall 103, an outer chamber surround the deposition chamber wall 102 to produce a vacuum state therebetween, and a strip substrate 101 is used as one of side walls of the film formation space. As the substrate is continuously moved in a longitudinal direction, a film forming gas is introduced into the film formation space through a gas supply means and simultaneously therewith, microwave energy is radiated from a microwave applicator means into the film formation space to produce microwave plasma and to continuously form a non- single crystalline semiconductor thin film on the moving strip substrate 101. In this case, cooling and temperature raising mechanisms are provided to cover an outer side of part of the deposition chamber wall 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for continuously forming a non-single-crystal semiconductor thin film. An apparatus and a method for mass-producing a photovoltaic element,
More specifically, the present invention relates to a means for controlling wall temperature and film formation gas introduction for obtaining a high-quality functional deposition film.

[0002]

2. Description of the Related Art In recent years, a power generation system using solar cells utilizing sunlight has been known to cause no problems such as radioactive contamination and global warming, and energy has been scattered throughout the earth. Sources are less unevenly distributed, and relatively high power generation efficiency can be obtained without the need for complicated and large-scale facilities.
Various research and development have been made as a clean power generation system that can respond without causing environmental destruction. By the way, for a power generation method using a solar cell, in order to establish it as one that meets the power demand, the solar cell used has sufficiently high photoelectric conversion efficiency and excellent characteristic stability, and It is basically required to be mass-produced. For this reason, a gaseous source gas such as silane, which can be easily obtained, is used, and is decomposed by glow discharge to form amorphous silicon (hereinafter referred to as “a-Si”) on a relatively inexpensive substrate such as glass or a metal sheet. The solar cell that can be manufactured by depositing a semiconductor thin film (such as abbreviated as ")" can be mass-produced and can be manufactured at a lower cost than a solar cell manufactured using single crystal silicon or the like. Attention has been paid to this, and various proposals have been made for the basic configuration manufacturing method and the like.

Conventionally, as a method for manufacturing a photovoltaic element,
The following techniques are known. For example, for manufacturing a photovoltaic element using a non-single-crystal semiconductor film or the like, generally, a plasma CVD method is widely used and commercialized.
However, it is basically required that the photovoltaic element has a sufficiently high photoelectric conversion efficiency, excellent characteristics stability, and can be mass-produced. For that purpose, in the production of a photovoltaic element using a non-single-crystal semiconductor film, etc., it is necessary to improve the electrical, optical, photoconductive, or mechanical properties and the fatigue properties in repeated use or the use environment properties. In addition to this, it is necessary to achieve reproducible mass production by high-speed film formation while increasing the area, making the film thickness and film quality uniform, and these are pointed out as problems to be improved in the future. ing.

In a power generation system using a photovoltaic element, a format in which unit modules are connected in series or in parallel to obtain a desired current and voltage by unitization is often adopted, and each module is disconnected. Is required that no short circuit occurs. In addition, it is important that there is no variation in output voltage or output current between the modules.
For this reason, it is required that the uniformity of the characteristics of the semiconductor layer itself, which is the largest characteristic determining factor, is secured at least at the stage of manufacturing the unit module. From the viewpoint of facilitating module design and simplifying the module assembling process, the provision of a semiconductor deposited film having excellent uniformity of characteristics over a large area increases the mass productivity of photovoltaic devices. Required to achieve significant reductions in production costs. When producing an amorphous silicon solar cell as one of efficient mass production methods of photovoltaic elements, an independent film forming chamber for each semiconductor layer is provided, and each semiconductor layer is provided in each film forming chamber. A method for forming a layer has been proposed.

[0005] By the way, US Patent No. 4,400,409
The specification includes a roll-to-roll.
A continuous plasma CVD apparatus adopting the (Roll) method is disclosed. According to this device, a plurality of glow discharge regions are provided, and a sufficiently long flexible substrate having a desired width is formed on the substrate while depositing a conductive semiconductor layer required in each of the glow discharge regions. By continuously transporting the substrate in the longitudinal direction, a device having a semiconductor junction can be continuously manufactured.
Note that, in this specification, a gas gate is used to prevent a dopant gas used in manufacturing each semiconductor layer from diffusing or mixing into another glow discharge region. Specifically, means for separating the glow discharge regions from each other by a slit-shaped separation passage and further applying a flow of a scavenging gas such as Ar or H ₂ to the separation passage is employed. . From this, it can be said that this roll-to-roll system is suitable for mass production of semiconductor devices.

[0006] However, the formation of each of the semiconductor layers is performed by R
When the plasma CVD method using F (radio frequency) is used, there is a natural limit to improving the film deposition rate while maintaining the characteristics of a continuously formed film. That is, for example, there is a method in which even when a semiconductor layer having a thickness of at most 2000 ° is formed, a predetermined plasma is generated over a large area at all times, and the plasma is uniformly maintained. However, this requires considerable skill and it is difficult to generalize the various plasma control parameters involved.
Further, the decomposition efficiency and utilization efficiency of the film-forming source gas used are not high, which is one of the factors for raising the production cost.

On the other hand, a plasma process using microwaves has recently attracted attention. Since microwaves have a short frequency, energy density can be increased as compared with the case of using conventional RF, and is suitable for efficiently generating and sustaining plasma. For example, US Pat. No. 4,729,341 discloses a high power process using a pair of radiating waveguide applicators.
A low-pressure microwave CVD method and apparatus for depositing and forming a photoconductive semiconductor thin film on a large-sized cylindrical substrate are disclosed. In view of the above situation, the microwave plasma CVD method (hereinafter referred to as “μW-CVD
The method is abbreviated as “method”) and the roll-to-roll production method is rationally combined to provide a mass production method with even higher throughput.

[0008]

However, the roll-to-roll μW-CVD method also has the following problems. The problem is that the input microwave power is not used only for the decomposition of the source gas for film deposition, but indirectly through a high plasma density, or the microwave itself directly forms a deposition space. This is to heat the room wall to a high temperature. The temperature of the deposition chamber wall begins to rise as soon as the microwave power is turned on, and after a certain time,
It reaches the equilibrium temperature determined by its discharge power value, etc.
The temperature can rise from 350 ° C. to 450 ° C. in some situations. As a result, the following problems occur. The first problem is that the temperature of the strip-like substrate for film deposition rises under the influence of the high deposition chamber wall temperature, and a high-quality deposited film is usually formed.
The inability to maintain a substrate temperature of about ° C. A solar cell manufactured under such a situation has low conversion efficiency. The second problem is that, depending on the material of the deposition chamber, the material reaches a temperature near the softening point of the material, and the wall of the deposition chamber is damaged. Specifically, for example, in the case where aluminum is used for the wall of the film forming chamber, at around 450 ° C., the screwed portion, the portion subjected to tensile stress, and the like are deformed and become unusable. In order to prevent such a situation, it is necessary to select a material having a high melting point or to provide a cooling means for preventing an increase in the temperature of the deposition chamber wall. Further, as a third problem, when a gas manifold for uniformly supplying a film forming gas into a film forming space is installed in a form in which a part of the wall of the above-mentioned deposition chamber is hollowed out, the deposition is performed as described above. Due to the rise in the temperature of the film chamber wall, a rise in the temperature of the gas manifold itself is observed, and in the gas manifold, the thermal decomposition of the film formation gas is promoted, and the initial characteristics of the solar cell, which should be obtained, are significantly reduced. In addition, the temperature rise in the gas manifold during the film formation for a long period of time causes a decrease in the uniformity of the characteristics.

[0009] From these problems, this roll-to-
Although the roll μW-CVD method is a method suitable for mass production of semiconductor devices, as described above, in order to spread a large number of photovoltaic elements, further photoelectric conversion efficiency,
It is desired to improve the property stability and the property uniformity and to reduce the manufacturing cost. In particular, in order to improve the photoelectric conversion efficiency and the characteristic stability, it is preferable that the photoelectric conversion efficiency of each unit module is higher and the characteristic deterioration rate is lower. Moreover,
When the unit modules are connected in series or in parallel to make a unit, the unit module with the minimum current or voltage characteristic among the unit modules constituting the unit is rate-determining and the characteristics of the unit are determined. It is very important not only to improve the average characteristics of the above, but also to reduce the variation in characteristics. Therefore, it is desired to ensure the uniformity of the characteristics of the semiconductor layer itself, which is the largest characteristic determining factor, at the stage of manufacturing the unit module. Further, in order to reduce the manufacturing cost, it is strongly desired to improve the yield by reducing the defects of the semiconductor layer so that the disconnection or short circuit does not occur in each module.

Accordingly, the present invention solves the above-mentioned problems in the conventional means for producing a photovoltaic element, has a high photoelectric conversion efficiency over a large area on a substrate, and has high quality and excellent uniformity. Provided is a method and an apparatus for forming a non-single-crystal semiconductor thin film with higher reproducibility and fewer defects, and in particular, to provide an apparatus and a method for forming a non-single-crystal semiconductor thin film for producing a large number of photovoltaic elements. It is an object.

[0011]

According to the present invention, there is provided a film deposition chamber having a film deposition space surrounded by a film deposition chamber wall and a strip-shaped substrate, and an outer chamber surrounding the deposition chamber wall. While moving in the longitudinal direction of the belt-like substrate, a film-forming gas is introduced into the film-forming space via gas supply means,
In an apparatus for generating microwave plasma by radiating microwave energy into the film forming space by microwave applicator means to form a non-single-crystal semiconductor thin film on the surface of the belt-like substrate, A non-single-crystal semiconductor thin film forming apparatus, wherein a cooling mechanism and a temperature raising mechanism are provided so as to cover a portion. Further, the present invention comprises a film deposition chamber having a film deposition space surrounded by a film deposition chamber wall and a strip-shaped substrate, and an outer chamber surrounding the deposition chamber wall, wherein the strip-shaped substrate is disposed in a longitudinal direction of the strip-shaped substrate. While moving, a film formation gas is introduced into the film formation space via a gas supply unit, and a plasma is generated in the film formation space,
An apparatus for forming a non-single-crystal semiconductor thin film on the surface of the strip-shaped substrate, wherein the gas supply means includes a gas manifold, and the gas manifold is provided apart from the film forming chamber wall. This is a thin film forming apparatus. Further, the present invention uses a semiconductor thin film forming apparatus including a film deposition chamber having a film deposition space surrounded by a film deposition chamber wall and a strip-shaped substrate, and an outer chamber surrounding the deposition chamber wall, and the strip-shaped substrate is While moving in the longitudinal direction of the belt-shaped substrate, a film forming gas is introduced into the film forming space through a gas supply unit, and microwave energy is emitted to the film forming space by a microwave applicator unit to generate microwave plasma. In the method of forming a non-single-crystal semiconductor thin film on the surface of the strip-shaped substrate, the thin film is formed while controlling the temperature by a cooling mechanism and a temperature raising mechanism provided so as to cover a part of the outer surface of the deposition chamber wall. And a method of forming a non-single-crystal semiconductor thin film. Further, the present invention uses a semiconductor thin film forming apparatus comprising a film deposition chamber having a film deposition space surrounded by a film deposition chamber wall and a band-shaped substrate, and an outer chamber surrounding the deposition chamber wall. While moving in the longitudinal direction of the belt-like substrate, a film-forming gas is introduced into the film-forming space via gas supply means, and plasma is generated in the film-forming space, and a non-single-crystal semiconductor thin film is formed on the surface of the belt-like substrate. Forming a non-single-crystal semiconductor thin film, wherein the gas supply means includes a gas manifold, and the gas manifold is provided apart from the film forming chamber wall. In addition, the present invention is a method for manufacturing a photovoltaic device, comprising the step of forming a non-single-crystal semiconductor thin film using the above-described forming method. When a microwave applicator is used in the present invention, the outer surface of the film deposition chamber includes a strip-shaped substrate surface, an applicator surface having the applicator means, an exhaust surface having gas exhaust means, and a normal surface other than these. However, it is preferable that the cooling mechanism and the temperature raising mechanism are provided on the applicator surface or the normal surface to adjust the temperature. Further, in the present invention, by providing a gas manifold for uniformly supplying a film-forming gas into the film-forming space away from the film-forming chamber wall, the gas manifold with the temperature rise of the film-deposition chamber wall is provided. It is possible to avoid a rise in temperature.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the present invention has a structure in which the temperature is controlled by a cooling mechanism and a temperature raising mechanism so as to cover a part of the outer wall of the deposition chamber wall, so that the energy of plasma can be used. A gas manifold that prevents a rise in the temperature of the deposition chamber wall surface, enables film deposition at a uniform temperature during a long-time film deposition process, and furthermore, supplies a deposition gas uniformly into the deposition space. Is disposed away from the deposition chamber, it is possible to avoid a rise in the temperature of the gas manifold due to a rise in the temperature of the wall of the deposition film chamber, and it is possible to suppress the thermal decomposition of the deposition gas in the gas manifold. Therefore, the output characteristics of the photovoltaic element can be improved, and a photovoltaic element having uniform characteristics can be provided, particularly by film deposition at a stable temperature for a long time. In this specification, a gas manifold is a chamber that divides a gas introduced from an introduction pipe into a number of flows. Further, according to the present invention, particularly in a stacked photovoltaic element, an extremely good pin junction can be realized, and a higher quality photovoltaic element can be uniformly formed with good reproducibility. .

Hereinafter, an example of a semiconductor thin film forming apparatus (film forming apparatus) of the present invention and a method of manufacturing a photovoltaic element using the same will be described in more detail with reference to the drawings. FIG. 1 is a schematic sectional view of a film forming apparatus showing an example of the present invention. In FIG. 1, reference numeral 101 denotes a band-shaped substrate, 102 denotes a film deposition chamber, 103 denotes a wall of the film deposition chamber, 104 denotes a cooling pipe for flowing a cooling medium for cooling the wall of the film deposition chamber, and 105 denotes an influence of the temperature of the film deposition chamber. A gas manifold installed away from the film deposition chamber wall to eliminate or reduce
Reference numeral 6 denotes a gas supply pipe (introduction pipe) for supplying a film forming gas to the gas manifold, and reference numeral 106a denotes a branch pipe for supplying a gas divided into a number of flows to a film deposition chamber. 1
Reference numeral 07 denotes an exhaust pipe during film formation, 108 denotes a gate valve, 109 denotes an oil diffusion pump, 110 denotes a roughing pipe, 1
10a is an L-shaped valve in the roughing pipe. 11
Reference numeral 1 denotes an i-type semiconductor layer film forming container in the present embodiment, but the present invention is not limited thereto. Numerals 112, 113, and 114 denote alumina ceramics, an applicator, and a waveguide, respectively, for introducing microwave power for generating microwave discharge in the film deposition chamber. Reference numerals 115 and 116 denote a lamp house and an infrared lamp heater for raising the temperature of the belt-like substrate to a predetermined temperature, respectively, and 117 denotes a thermocouple for control. 1
Reference numeral 18 denotes a bias rod for applying RF power.
Reference numeral 19 denotes a wall heater for raising the temperature of the deposited film wall to a predetermined temperature. FIG. 2 is an example of a cross-sectional view of a photovoltaic element manufactured by the film forming apparatus of the present invention. However, the present invention is not limited only to manufacturing the photovoltaic element having the configuration shown in FIG. In FIG. 2, 201 is a substrate, 2
02 is a back electrode, 203 is an n-type semiconductor layer, 204 is an i-type semiconductor layer, 205 is a p-type semiconductor layer, 206 is a transparent electrode,
207 is a current collecting electrode. FIG. 2 shows a structure in which light enters from the p-type semiconductor layer side. In the case of a photovoltaic element having a structure in which light enters from the n-type semiconductor layer side, 203 is the p-type semiconductor layer and 204 is the i-type semiconductor layer. Type semiconductor layer, 205
Type semiconductor layer. Further, FIG. 2 shows a configuration in which light is incident from the side opposite to the substrate. In a photovoltaic element having a configuration in which light is incident from the substrate side, the positions of the transparent electrode and the current collecting electrode are reversed, and 202 is a transparent electrode. , 203 are the p-type semiconductor layers, 20
5 is the i-type semiconductor layer; 204 is the n-type semiconductor layer;
05 may be the back electrode. FIG. 3 is an example of a cross-sectional view of a stacked photovoltaic element manufactured by the film forming apparatus of the present invention. The stacked photovoltaic device of the present invention in FIG. 3 has a structure in which three pin junctions are stacked,
315 is a first pin junction counting from the light incident side, 316
Is a second pin junction, and 317 is a third pin junction. These three pin junctions are formed on the back electrode 302 formed on the substrate 301, and the transparent electrode 313 and the current collecting electrode 3 are formed on the top of the three pin junctions.
14 are formed to form a stacked photovoltaic element. Each of the pin junctions is connected to the n-type semiconductor layer 3.
03, 306, 310, i-type semiconductor layers 304, 308,
311 and p-type semiconductor layers 305, 309 and 312. Also, like the photovoltaic element of FIG. 1, the doping layer (p-type semiconductor layer, n-type semiconductor layer) depends on the incident direction of light.
And the arrangement of the electrodes may be interchanged.

The non-single-crystal silicon photovoltaic element according to the present invention will now be described with respect to the substrate, back electrode, light reflecting layer, semiconductor layer, transparent electrode, and current collecting electrode. First, the substrate will be described. The semiconductor layers 203 to 205 and 303 to 31 of the present invention are described.
2 is a thin film having a thickness of at most about 1 μm and is deposited on an appropriate substrate.
They may be single crystalline or non-single crystalline, and they may be conductive or electrically insulating. Furthermore, they may be translucent or non-translucent,
It is preferable that the material has little deformation and distortion and a desired strength. Specifically, Fe, Ni, Cr, Al, M
o, Au, Nb, Ta, V, Ti, Pt, Pb and other metals or alloys thereof, such as brass, stainless steel and other thin plates and composites thereof, and polyester, polyethylene,
Film or sheet of heat-resistant synthetic resin such as polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, epoxy or composite of these with glass fiber, carbon fiber, boron fiber, metal fiber, etc. A thin metal film of different materials and / or Si
Examples thereof include those obtained by subjecting an insulating thin film such as O ₂ , Si ₃ N ₄ , Al ₂ O ₃ , or AlN to a surface coating treatment by a sputtering method, a vapor deposition method, a plating method, or the like, glass, ceramics, and the like.

When the substrate is electrically conductive such as a metal, it may be used as an electrode for direct current extraction. When the substrate is electrically insulating such as a synthetic resin or the like, the surface on the side where the deposited film is formed is coated with Al. , Ag, Pt, Au, Ni, Ti, Mo, W,
So-called metal simple substance or alloy such as Fe, V, Cr, Cu, stainless steel, brass, nichrome, SnO ₂ , In ₂ O ₃ , ZnO, ITO (indium tin oxide), and transparent conductive oxide (TCO) It is preferable that a surface treatment is performed in advance by a method such as vapor deposition or sputtering to form an electrode for extracting current. Of course, even if the substrate is an electrically conductive material such as a metal, the reflectance of long-wavelength light on the substrate surface is improved, and the mutual diffusion of constituent elements between the substrate material and the deposited film is prevented. A different kind of metal layer or the like may be provided on the side of the substrate on which the deposited film is formed, for the purpose of, for example, performing a process.
Further, when the substrate is relatively transparent and a photovoltaic element having a layer structure in which light enters from the side of the substrate is used, a conductive thin film such as the transparent conductive oxide or a metal thin film is previously deposited. It is desirable to form it. The surface of the substrate may be a so-called smooth surface or a surface having minute irregularities. When the surface has minute irregularities, the irregularities are spherical, conical, pyramidal, or the like, and the maximum height (Rmax) is preferably 0.1 mm.
When the thickness is from 05 μm to 2 μm, light reflection on the surface becomes irregular reflection, and the optical path length of the light reflected on the surface is increased.

The shape of the substrate can be a plate having a smooth surface or an uneven surface, a long belt, a cylinder, or the like, depending on the application, and the thickness thereof can form a desired photovoltaic element. However, when flexibility is required as the photovoltaic element, or when light is incident from the side of the substrate, as much as possible within the range where the function as the substrate is sufficiently exhibited. It can be thin. However, from the viewpoints of mechanical strength and the like in manufacturing and handling the substrate,
It is 10 μm or more.

Next, the back electrode will be described. The back electrodes 202 and 302 used in the present invention are electrodes arranged on the back surface of the semiconductor layer in the light incident direction. Therefore, at the position 202 in FIG. 2 or when the substrate 201 is translucent and light is incident from the direction of the substrate, 20
6 are arranged. Gold,
Examples include metals such as silver, copper, aluminum, nickel, iron, chromium, molybdenum, tungsten, titanium, cobalt, tantalum, niobium, and zirconium, and alloys such as stainless steel. Among them, metals having high reflectance, such as aluminum, copper, silver, and gold, are particularly preferable. In the case of using a metal having a high reflectance, the back electrode can also serve as a light reflecting layer for reflecting light that could not be absorbed by the semiconductor layer again to the semiconductor layer. The shape of the back electrode may be flat, but it is more preferable that the back electrode has an uneven shape for scattering light. By having an uneven shape that scatters light, it scatters long-wavelength light that could not be absorbed by the semiconductor layer, extends the optical path length in the semiconductor layer, improves the long-wavelength sensitivity of the photovoltaic element, and increases the short-circuit current. And the photoelectric conversion efficiency can be improved. It is desirable for the uneven shape that scatters light that the maximum value Rmax of the difference between the heights of the peaks and valleys of the unevenness be 0.2 μm to 2.0 μm. However, when the substrate also serves as the back electrode, the back electrode may not need to be formed in some cases. In addition, a vapor deposition method, a sputtering method, a plating method, a printing method, or the like is used for forming the back surface electrode. In the case of forming an uneven shape for scattering light on the back electrode, the metal or alloy film provided on the substrate is formed by dry etching, wet etching, sandblasting, heating, or the like. You. In addition, the above-mentioned metal or alloy can be deposited while heating the substrate to form an uneven shape for scattering light. Although not shown in the figure, a diffusion preventing layer such as conductive zinc oxide may be provided between the back electrodes 202 and 302 and the n-type semiconductor layers 203 and 303.
The effect of the diffusion preventing layer is not only to prevent the metal element constituting the back electrode 202 from diffusing into the n-type semiconductor layer, but also to provide a slight resistance value so that the back surface provided with the semiconductor layer interposed therebetween. The effect of preventing short-circuiting caused by a defect such as a pinhole between the electrode 202 and the transparent electrode 206 and the effect of generating multiple interference by a thin film and confining incident light in a photovoltaic element are given. Can be.

For the semiconductor layer used in the present invention, a non-single-crystal semiconductor, specifically, an amorphous semiconductor, a microcrystalline semiconductor, or a polycrystalline semiconductor is used. The material is Si,
Those using group IV elements such as C and Ge, or SiG
Those using a group IV alloy such as e, SiC, SiSn are preferably used. Among the above semiconductor materials, a-Si: H (abbreviation for hydrogenated amorphous silicon), a semiconductor material particularly preferably used for the photovoltaic element of the present invention,
a-Si: F, a-Si: H: F, a-SiGe: H,
a-SiGe: F, a-SiGe: H: F, a-Si
Group IV and group IV alloy-based amorphous semiconductor materials such as C: H, a-SiC: F, and a-SiC: H: F. Also,
Microcrystalline semiconductor materials made of these group IV and group IV alloys are also preferably used. The semiconductor layer can perform valence electron control and forbidden band width control. Specifically, a raw material compound containing an element serving as a valence electron controlling agent or a forbidden band width controlling agent when forming a semiconductor layer is used alone, or mixed with the deposited film forming raw material gas or the diluent gas to form a film. You only have to introduce it in the space. In addition, at least a part of the semiconductor layer is doped into p-type and n-type by valence electron control to form at least one pair of pin junctions. By stacking a plurality of pin junctions, a so-called stacked cell configuration is obtained.

Hereinafter, particularly suitable for the photovoltaic device of the present invention.
The semiconductor layer using a group IV or group IV alloy non-single-crystal semiconductor material will be described in more detail. (1) i-type semiconductor layer (intrinsic semiconductor layer) Particularly in a photovoltaic device using a group IV or group IV alloy-based non-single-crystal semiconductor material, the i-type layer used for the pin junction has a carrier against irradiation light. Is an important layer to transport. i
Group IV and Group IV alloy-based non-single-crystal semiconductor materials, in which a slight p-type and a slight n-type layer can be used as the mold layer, include:
As described above, a hydrogen atom (H, D) or a halogen atom (X) is contained, and this has an important function. Hydrogen atoms (H, D) or halogen atoms (X) contained in the i-type layer work to compensate for dangling bonds in the i-type layer, and the carrier mobility in the i-type layer. And product life. P-type layer / i-type layer, n
Works to compensate the interface state of each interface of the mold layer / i-type layer,
This has the effect of improving the photovoltaic power, photocurrent and photoresponsiveness of the photovoltaic element. The optimal content of hydrogen atoms and / or halogen atoms contained in the i-type layer is 1 to 40 at%. In particular, p-type layer / i-type layer, n
A preferred distribution form includes a large distribution of the content of hydrogen atoms and / or halogen atoms at each interface side of the mold layer / i-type layer.
And the content of halogen atoms is 1.1 times the content in the bulk.
A range of up to 2 times is mentioned as a preferable range. Further, it is preferable that the content of hydrogen atoms and / or halogen atoms is changed in accordance with the content of silicon atoms. In the stacked photovoltaic device, the material of the pin-type i-type semiconductor layer close to the light incident side is as follows.
As a material having a wide band gap and a material of a pin junction i-type semiconductor layer far from the light incident side, a material having a narrow band gap is preferably used.

Amorphous silicon and amorphous silicon germanium are formed by an element that compensates for dangling bonds.
a-Si: H, a-Si: F, a-Si: H: F, a-
SiGe: H, a-SiGe: F, a-SiGe: H:
It is written as F or the like. Further, as the characteristics of the i-type semiconductor layer suitable for the photovoltaic device of the present invention, the hydrogen atom content (C _H ) is 1.0 to 25.0%, AM 1.5, 100
Photoconductivity (σp) under mW / cm ² simulated sunlight irradiation
Is at least 1.0 * 10 ^-7 S / cm, and the dark conductivity (σd)
However, those having an energy of 1.0 * 10 < ^-9 > S / cm or less, an Urbach energy of 55 meV or less by a constant photocurrent method (CPM), and a localized level density of 10 < ¹⁷ > / cm < ³ > or less are preferably used.

(2) P-type semiconductor layer or n-type semiconductor layer As an amorphous material (denoted as a-) or a microcrystalline material (denoted as μc-) of a p-type semiconductor layer or an n-type semiconductor layer, For example, a-Si: H, a-Si: HX, a-S
iGe: H, a-SiGe: HX, μc-Si: H, μ
c-SiGe: H, μc-SiGe: HX, etc., p-type valence electron controlling agents (Group III atoms B, Al, Ga,
In, Tl) and a material in which an n-type valence electron controlling agent (Group V atom P, As, Sb, Bi) in the periodic table is added at a high concentration, and as a polycrystalline material (denoted as poly-). Is, for example, poly-Si: H, poly-Si: H
X, poly-SiGe: H, poly-SiGe: H
X, poly-Si, poly-SiGe, etc., a p-type valence electron controlling agent (Group III atom B, Al, Ga,
In, Tl) or a material in which an n-type valence electron controlling agent (Group V atom P, As, Sb, Bi) in the periodic table is added at a high concentration. In particular, a crystalline semiconductor layer with little light absorption or an amorphous semiconductor layer with a wide band gap is suitable for the p-type layer or the n-type layer on the light incident side.

The addition amount of Group III atoms of the periodic table to the p-type layer and the addition amount of Group V atoms of the periodic table to the n-type layer are 0.1
５０50 at% (atom%) is mentioned as the optimum amount. Hydrogen atoms (H, D) or halogen atoms contained in the p-type layer or the n-type layer work to compensate for dangling bonds of the p-type layer or the n-type layer, and doping efficiency of the p-type layer or the n-type layer. Is to improve. A hydrogen atom or a halogen atom added to the p-type layer or the n-type layer is 0.1 to
40 at% is mentioned as the optimum amount. In particular, when the p-type layer or the n-type layer is crystalline, the optimum amount of hydrogen atoms or halogen atoms is 0.1 to 8 at%. And p
A preferable distribution form is one in which a large amount of hydrogen atoms and / or halogen atoms is distributed on each interface side of the n-type layer / i-type layer and the n-type layer / i-type layer. The preferred range of the content of atoms and / or halogen atoms is 1.1 to 2 times the content in the bulk. By increasing the content of hydrogen atoms or halogen atoms in the vicinity of each interface between the p-type layer / i-type layer and the n-type layer / i-type layer, the defect level and mechanical strain near the interface are reduced. Accordingly, the photovoltaic power and the photocurrent of the photovoltaic device of the present invention can be increased. The p-type and n-type layers of the photovoltaic element preferably have an activation energy of 0.2 eV or less, and most preferably have an activation energy of 0.1 eV or less. The specific resistance is preferably 100 Ωcm or less, and most preferably 1 Ωcm or less. Further, the thickness of the p-type layer and the n-type layer is preferably 1 to 50 nm, and 3 to 1 nm.
0 nm is optimal.

In the present invention, the transparent electrodes 206, 313
Is an electrode on the light incident side that transmits light, and also functions as an anti-reflection film by optimizing the film thickness. The transparent electrodes 206 and 313 are required to have a high light transmittance in a wavelength region where the semiconductor layer can absorb light and have a low electric resistivity. Preferably, 550n
m is 80% or more, more preferably 8% or more.
It is desirable that it be 5% or more. The resistivity is preferably 5 * 10 ⁻³ Ωcm or less, more preferably 1 * 1 Ωcm.
Desirably, it is 0 ⁻³ Ωcm or less. The materials include In ₂ O ₃ , SnO ₂ , and ITO (In ₂ O ₃ + Sn
O ₂ ), ZnO, CdO, Cd ₂ SnO ₄ , TiO ₂ , Ta
A conductive oxide such as ₂ O ₅ , Bi ₂ O ₃ , MoO ₃ , and Na _x WO ₃ or a mixture thereof is suitably used.
Further, an element (dopant) that changes the conductivity may be added to these compounds.

As the element (dopant) for changing the conductivity, for example, when the transparent electrodes 206 and 313 are made of ZnO, Al, In, B, Ga, Si, F, etc.
_In the case of ₂ O ₃ , Sn, F, Te, Ti, Sb, Pb, etc., and in the case of SnO ₂ , F, Sb, P, As, I
n, Tl, Te, W, Cl, Br, I and the like are preferably used.

As a method for forming the transparent electrodes 206 and 313, a vapor deposition method, a CVD method, a spray method, a spin-on method, a dipping method and the like are suitably used.

In the present invention, the collecting electrodes 207 and 314
Is formed on a part of the transparent electrode 206 as necessary when the resistivity of the transparent electrodes 206 and 313 cannot be made sufficiently low, and serves to lower the resistivity of the electrode and reduce the series resistance of the photovoltaic element. Examples of the material include metals such as gold, silver, copper, aluminum, nickel, iron, chromium, molybdenum, tungsten, titanium, cobalt, tantalum, niobium, and zirconium; alloys such as stainless steel; and conductive materials using powdered metals. Paste and the like. The shape is formed so as not to block incident light on the semiconductor layer as much as possible. Also, the area occupied by the collecting electrode in the entire area of the photovoltaic element is preferably 15%.
Or less, more preferably 10% or less, and most preferably 5% or less. In addition, a mask is used to form the pattern of the collecting electrode, and a vapor deposition method, a sputtering method, a plating method, a printing method, or the like is used as a forming method.

In the present invention, the material of the members constituting the film deposition chamber wall 102 may be conductive or electrically insulating. It is preferable that the material has little deformation and distortion and a desired strength. Specifically, Fe, Ni, Cr, Al, Mo, Au, Nb, T
Metals such as a, V, Ti, Pt, Pb, and W or alloys thereof, for example, thin plates such as brass and stainless steel and composites thereof are suitably used. Further, a metal thin film of a different metal material or SiO ₂ , Si ₃ N ₄ , A
lO _3, sputtering an insulating film such as AlN, vapor deposition,
Those coated by plating or the like, glass, ceramics, or the like may be used.

In the present invention, the material of the cooling pipe 104 for flowing the cooling medium for cooling the wall of the deposition chamber is heat-resistant,
Those having corrosion resistance are preferred. Specifically, a metal such as stainless steel is suitably used. As a configuration of the cooling pipe 104, a pipe formed from the above metal may be bolted to a deposited film wall by a push plate,
The metal may be cut so as to have a cavity. Further, the plurality of metals processed into an uneven shape may be subjected to special processing such as electric discharge machining, welding, or the like to have a coolant passage.

The heater 119 for heating the deposited film wall may be any type such as a sheath type heater or a lamp type heater as long as it can be used in a vacuum.
In particular, a halogen infrared lamp heater is preferably used because of the responsiveness of the temperature control mechanism and the reliability of use in a vacuum.

The material of the coolant for cooling the deposition chamber wall can be appropriately selected depending on the desired temperature of the deposition film wall.
Water, compressed air, or the like is preferably used as the refrigerant for ease of handling, and when the desired temperature is high, synthetic oil or the like is preferably used. Incidentally, using the photovoltaic element of the present invention,
When manufacturing a photovoltaic device module or a photovoltaic device panel having a desired output voltage and output current, the photovoltaic devices of the present invention are connected in series or in parallel, and a protective layer is formed on the front and back surfaces. , An output extraction electrode and the like are attached. When the photovoltaic elements of the present invention are connected in series, a diode for preventing backflow may be incorporated.

An example of an apparatus for manufacturing a photovoltaic element according to the present invention will be described below with reference to FIG. FIG. 4 is a schematic diagram illustrating an example of a manufacturing apparatus for continuously manufacturing the photovoltaic element of the present invention, in which the i-type semiconductor layer film formation container 111 illustrated in FIG. 1 is incorporated. This manufacturing apparatus includes a feeding chamber 402 for a strip-shaped substrate 401, a winding chamber 403, an n-type semiconductor layer manufacturing container 404, an i-type semiconductor layer manufacturing container 405, and a p-type semiconductor layer manufacturing container 406.
Are connected via a gas gate. 407 is a bobbin for sending out the band-shaped substrate 401;
Reference numeral 8 denotes a bobbin for winding the belt-shaped substrate 401;
The belt-shaped substrate 401 is transported in a direction from to 408. However, the band-shaped substrate 401 can be transported in the opposite direction. Also, in the feeding room 402 and the winding room 403,
Means for winding and feeding the interleaving paper used for protecting the surface of the band-shaped substrate 401 may be arranged. As the material of the interleaf paper, a heat-resistant resin such as a polyimide-based resin, a Teflon-based resin, or glass wool is preferably used. Also,
Band-shaped substrate 4 as winding means and feeding means for the paper
It is also possible to use a transport roller that also serves as a tension adjustment and positioning device for the “01”. Reference numeral 410 denotes a film forming gas inlet, which communicates with a gas supply mixing box (not shown). 420
Denotes a gate gas introduction pipe for introducing a gate gas for separating a film forming gas between film forming chambers. Reference numeral 411 denotes a throttle valve for adjusting the conductance, and 412 denotes an exhaust pipe, which is connected to an exhaust pump (not shown). 413
Denotes an applicator, and a microwave permeable member is attached to the tip of the applicator. The applicator is connected to a microwave power supply (not shown) through a waveguide 414.

An electrode 415 is connected to a power supply 416. In each of the film forming containers 404, 405, and 406, a large number of infrared lamp heaters 417 and the radiant heat from these infrared lamp heaters are efficiently band-shaped in a space opposite to the film forming space with the band-shaped substrate 401 interposed therebetween. A lamp house 418 for concentrating on the substrate 401 is provided. Further, thermocouples 419 for monitoring the temperature of the band-shaped substrate 401 are connected so as to be in contact with the band-shaped substrate 401, respectively.

In the present invention, a bias voltage may be applied to control the plasma potential of the microwave plasma generated in the film formation space. DC as bias voltage,
It is preferable to apply the pulsating current and the AC voltage individually or in a superimposed manner. By controlling the plasma potential of the microwave plasma, plasma stability, reproducibility, film characteristics are improved, and defects are reduced. Also,
The present invention is effective not only when plasma is generated by microwaves but also when plasma is generated by VHF waves. By using a device for continuous photovoltaic device of the present invention described above, by producing a photovoltaic device,
It is possible to manufacture a photovoltaic element which solves the above-mentioned problems and satisfies the above-mentioned requirements, has high quality and excellent uniformity, and has few defects.

[0034]

EXAMPLES Hereinafter, specific examples of the method of manufacturing a photovoltaic device according to the present invention will be described, but the present invention is not limited to these examples. Example 1 Using the apparatus shown in FIG. 4, photovoltaic elements were continuously manufactured as follows. (1) A vacuum vessel (delivery chamber) 402 having a substrate delivery mechanism is sufficiently degreased and washed, and a silver thin film having a thickness of 100 nm and Z is formed as a lower electrode by a sputtering method.
SUS430BA strip-shaped substrate 401 (width 300 mm x length 300 m x thickness 0.2
mm), and the band-shaped substrate 401 is connected to the n-type semiconductor layer deposition container 404, the i-type semiconductor layer deposition container 405, and the p-type semiconductor layer deposition container 406 via a gas gate. The sheet was passed through a vacuum container (winding chamber) 403 having a belt-shaped substrate winding mechanism, and the tension was adjusted to a degree that there was no slack. (2) Each vacuum vessel 402, 403, 404, 405, 4
06 was evacuated to 1 × 10 ⁻⁶ Torr or less using a vacuum pump (not shown). (3) Heat treatment before film formation: 500 cc / H ₂ as a gate gas from the gate gas inlet pipe 420 to the gas gate.
500 cc / min of He is introduced from the gas introduction pipe 420 into each of the film forming vessels, and the vacuum vessels 402 and 40 are introduced.
The opening degree of the throttle valve 411 was adjusted so that the internal pressures of 3, 404, 405, and 406 became 1.0 Torr, and each vacuum vessel was evacuated by a vacuum pump (not shown) through the exhaust pipe 412 of each vacuum vessel. . Thereafter, the belt-shaped substrate and the members inside the vacuum vessel were heated to 400 ° C. by the heating lamp heater 417, and left in this state for 3 hours. (4) Each vacuum vessel 402, 403, 404, 405, 4
06 was evacuated to 1 × 10 ⁻⁶ Torr or less using a vacuum pump (not shown). (5) Gate gas introduction at the time of film formation: 500 g of H ₂ as a re-gate gas from each gate through the gate gas introduction pipe 420.
c / min was introduced. (6) Preparation for film formation of n-type semiconductor layer: thermocouple temperature indicated value is 2
A temperature controller (not shown) was set so as to reach 70 ° C., and the band-shaped substrate 401 was heated by the infrared lamp heater 417. SiH ₄ gas is supplied at 100 cc / min from the film forming gas inlet 410 to the container 404 for forming an n-type semiconductor layer.
500 cc / min of H ₃ / H ₂ (1%) gas and 700 cc / min of H ₂ gas were introduced. The discharge chamber pressure is 1.0
The conductance adjusting valve 411 is set to Torr.
Was adjusted and the air was exhausted by a vacuum pump (not shown) through the exhaust pipe 412. The output value of the RF (13.56 MHz) power supply 416 was set to be 100 W, and a discharge was generated in the discharge chamber through the electrode. (7) Preparation for i-type semiconductor layer film formation: thermocouple temperature indication value is 3
A temperature controller (not shown) was set so as to reach 60 ° C., and the band-shaped substrate 401 was heated by the infrared lamp heater 417. SiH ₄ gas is supplied from the gas manifold 422 to the i-type semiconductor layer forming container 405 through the gas introduction pipe.
0 cc / min, 50 cc / min of GeH ₄ gas, H ₂
Gas was introduced at 200 cc / min. The discharge chamber pressure is 2
The opening degree of the throttle valve 411 for adjusting the conductance was adjusted to 0 mTorr, and the air was evacuated by a vacuum pump (not shown). Microwave (2.45 GHz) power was introduced into the applicator 413, and 200 W of microwave power was introduced through the microwave permeable member to cause discharge in the discharge chamber. Water was allowed to flow through the film deposition chamber wall cooling pipe 421, and the film deposition chamber was controlled to be constant at 200 ° C. by a film deposition chamber wall heater (not shown) while cooling the film deposition chamber. (8) Preparation for film formation of p-type semiconductor layer: temperature indication value of thermocouple is 1
A temperature controller (not shown) was set so as to reach 70 ° C., and the band-shaped substrate 401 was heated by the infrared lamp heater 417. 10 cc / min of SiH ₄ gas and BH ₃ / H ₂ gas are introduced into the p-type semiconductor layer forming container 406 from the gas inlet 410.
(1%) gas at 200 cc / min, H ₂ gas at 100
0 cc / min is introduced. Discharge chamber pressure is 1.0 Torr
The opening degree of the conductance adjusting throttle valve 411 was adjusted to r, and the gas was exhausted by a vacuum pump (not shown) through the exhaust pipe 412. The output value of the RF power supply 416 was set to be 1000 W, and a discharge was generated in the discharge chamber through the electrodes. (9) The strip-shaped substrate 401 was transported from the delivery chamber 402 to the winding chamber 403 at a speed of 1300 mm / min, and an n-type semiconductor layer, an i-type semiconductor layer, and a p-type semiconductor layer were formed on the strip-shaped substrate. (10) After transporting one roll of the strip-shaped substrate, all plasma, all gas supply, energization of all lamp heaters, and transfer of the strip-shaped substrate were stopped. Next, N ₂ gas for chamber leak was introduced into the chamber (introduction member not shown), the pressure was returned to the atmospheric pressure, and the belt-shaped substrate wound on the winding bobbin 408 was taken out. (11) As a transparent electrode on the p-type semiconductor layer, ITO (I
n ₂ O ₃ + SnO ₂ ) by vacuum evaporation to a thickness of 100 nm,
Further, as a current collecting electrode, Al was vapor-deposited by 1 μm by vacuum vapor deposition to produce a photovoltaic element (sample No. 1) shown in FIG. Table 1 shows the conditions for manufacturing the above photovoltaic element.

[0035]

[Table 1] (Comparative Example 1) In this example, a photovoltaic element was manufactured in the same manner as in Example 1 except that the heating temperature of the strip-shaped substrate in the diffusion preventing layer was kept constant. Hereinafter, differences from the first embodiment will be summarized. (1) The same conditions were used except that water cooling of the i-type semiconductor layer deposited film wall was not performed and the gas manifold was formed by an apparatus integrated with the film deposition chamber wall. In other respects, a photovoltaic element (Comparative Sample No. 1) was fabricated on a one-roll band-shaped substrate in the same manner as in Example 1. First, for each of the photovoltaic device obtained in Example 1 (Sample No. 1) and the photovoltaic device obtained in Comparative Example 1 (Comparative Sample No. 2), the photoelectric conversion efficiency η = ｛per unit area Maximum generated power (mW
/ Cm ² ) / incident light intensity per unit area (mW / c
m ² )｝ was evaluated. Sample No. of Example 1 No. 1 and Comparative Sample No. 1 of Comparative Example 1. 5 photovoltaic elements were manufactured, and AM-1.5 (100 mW / c
m ² ) Place under light irradiation, apply DC voltage to upper electrode,
The current-voltage characteristics were measured, and the open-circuit voltage, fill factor, and photoelectric conversion efficiency η were evaluated. 1
For the photovoltaic element of Sample No. The photovoltaic element of No. 1 had an open-circuit voltage value of 1.14 times on average, a fill factor value of 1.1 times on average, and a photoelectric conversion efficiency η of 1.25 times on average. Further, each of the photovoltaic element manufactured in Example 1 and the photovoltaic element manufactured in Comparative Example 1 (Comparative Sample No. 1) was made of polyvinylidene fluoride (VD
F) Vacuum sealed with a protective film made of F), under actual use conditions (installed outdoors, connect a fixed resistance of 50 ohms to both electrodes)
After one year, the photoelectric conversion efficiency was evaluated again, and the deterioration rate due to light irradiation (the value of the photoelectric conversion efficiency damaged by the deterioration divided by the initial photoelectric conversion efficiency) was examined. As a result, the deterioration rate of the photovoltaic device (Sample No. 1) on which the diffusion preventing layer according to the present invention was formed was determined by the conventional method.
o. The ratio to the deterioration rate of 1) was suppressed to as low as 40%. From the above, it has been found that the photovoltaic element manufactured according to the present invention dramatically improves the photoelectric conversion efficiency and greatly improves the reliability under actual use conditions.

Example 2 An n-type semiconductor layer, an i-type semiconductor layer, a p-type semiconductor layer, a transparent electrode, and an i-type semiconductor layer were prepared in the same manner as in Example 1 except that the manufacturing conditions for the i-type semiconductor layer were changed to Table 2. Current collecting electrodes were sequentially formed to produce a photovoltaic element (Sample No. 2).

[0037]

[Table 2] (Comparative Example 2) In this example, a photovoltaic element was manufactured in the same manner as in Example 2 except for the manufacturing conditions of the i-type semiconductor layer. Hereinafter, differences from the second embodiment will be summarized. (1) Water cooling of the film deposition chamber wall for the i-type semiconductor layer is not performed,
The conditions were the same except that the gas manifold was made with an apparatus integrated with the film deposition chamber wall. In other respects, a photovoltaic element (Comparative Sample No. 2) was produced on a one-roll band-shaped substrate in the same manner as in Example 2. First, the photoelectric conversion efficiency η of each of the photovoltaic device obtained in Example 2 (Sample No. 2) and the photovoltaic device obtained in Comparative Example 2 (Comparative Sample No. 2) was evaluated. . In the sample No. of Example 2, No. 2 and Comparative Sample No. 2 of Comparative Example 2. 5 of each photovoltaic element were manufactured, and AM-1.5 (100
mW / cm ² ) The sample was placed under light irradiation, a DC voltage was applied to the upper electrode, current-voltage characteristics were measured, and the open-circuit voltage, fill factor, and photoelectric conversion efficiency η were evaluated. For the photovoltaic element of Sample No. 2, The photovoltaic element of No. 1 has an open-circuit voltage value of 1.17 times on average, a fill factor value of 1.1 times on average, and a photoelectric conversion efficiency η.
Was 1.3 times better on average. Further, each of the photovoltaic element manufactured in Example 2 and the photovoltaic element (Comparative Sample No. 1) manufactured in Comparative Example 2 was vacuum-sealed with a protective film made of polyvinylidene fluoride (VDF). After one year under the condition of use (installed outdoors, fixed resistance of 50 ohms connected to both electrodes), the photoelectric conversion efficiency was evaluated again, and the deterioration rate due to light irradiation (photoelectric conversion damaged by deterioration) (Efficiency value divided by initial photoelectric conversion efficiency). As a result, the deterioration rate of the photovoltaic device (Sample No. 2) having the diffusion prevention layer according to the present invention was lower than that of the photovoltaic device (Comparative Sample No. 2) having the i-type semiconductor layer formed by the conventional method. It was as low as 50% of the rate of deterioration. From the above, it has been found that the photovoltaic element manufactured according to the present invention dramatically improves the photoelectric conversion efficiency and greatly improves the reliability under actual use conditions.

[Embodiment 3] In this embodiment, when the i-type semiconductor layer is manufactured in Embodiment 1, the wall of the film deposition chamber is controlled to be constant at 200 ° C., but the cooling medium is changed from water to oil. By doing so, it was realized that the temperature became constant at 330 ° C., and an experiment was performed. Other conditions are the same as those in the first embodiment, and an n-type semiconductor layer, an i-type semiconductor layer, a p-type semiconductor layer, a transparent electrode and a current collecting electrode are sequentially formed, and a photovoltaic element (sample N
o. 3) was produced.

(Comparative Example 3) First, each of the photovoltaic element (sample No. 3) obtained in Example 3 and the photovoltaic element (comparative sample No. 2) obtained in Comparative Example 2 was subjected to photoelectric conversion. The conversion efficiency η was evaluated.

The sample No. of Example 3 3 and Comparative Sample No. 2 of Comparative Example 2. 5 each of 5 photovoltaic elements were manufactured, placed under AM-1.5 (100 mW / cm ² ) light irradiation, a DC voltage was applied to the upper electrode, and the current-voltage characteristics were measured. Fill factor and photoelectric conversion efficiency η
Was evaluated, and Comparative Sample No. For the photovoltaic element of Sample No. 2, The photovoltaic element of No. 1 had an open-circuit voltage value of 1.19 times on average, a fill factor value of 1.2 times on average, and a photoelectric conversion efficiency η of 1.4 times on average. Further, each of the photovoltaic device manufactured in Example 2 and the photovoltaic device (Comparative Sample No. 1) manufactured in Comparative Example 2 was vacuum-sealed with a protective film made of polyvinylidene fluoride (VDF), After one year under actual use conditions (installed outdoors, connecting a fixed resistance of 50 ohms to both electrodes), the photoelectric conversion efficiency was evaluated again, and the degradation rate due to light irradiation (photoelectric damage caused by degradation) (The value of the conversion efficiency divided by the initial photoelectric conversion efficiency). As a result, the deterioration rate of the photovoltaic device having the p-type semiconductor layer formed according to the present invention (Sample No. 3) was reduced by the conventional method. Was suppressed to as low as 50% of the deterioration rate.

From the above, it has been found that the photovoltaic device manufactured according to the present invention has a remarkable improvement in photoelectric conversion efficiency and a great improvement in reliability under actual use conditions.

[Embodiment 4] In this embodiment, instead of providing a set of pin junctions on the surface of the lower electrode in Embodiment 1,
A set of pin junctions were used in a stack. When three sets of pin junctions are stacked in this way, it is called a triple type photovoltaic element. Here, the discharge generating means for forming the i-type semiconductor layer at the pin junction on the light incident side is RF
The same operation as in Example 1 was performed except that discharge was performed. When manufacturing the triple type photovoltaic element, a container for forming an n-type semiconductor layer is newly provided between the container 406 for forming a p-type semiconductor layer and the winding chamber 403 of the deposition film forming apparatus shown in FIG. , I
Equipment in which a container for forming a p-type semiconductor layer, a container for forming a p-type semiconductor layer, a container for forming an n-type semiconductor layer, a container for forming an i-type semiconductor layer, and a container for forming a p-type semiconductor layer are connected via respective gas gates. Was used. The i-type semiconductor layers of the first and second pin junctions were formed of a-SiGe: H, and the i-type semiconductor layers of the third pin junction were formed of a-Si: H, respectively. The manufacturing conditions are shown in Table 3. The stacking order is the order from the upper column to the lower column of Table 3. Subsequently, the produced photovoltaic element was processed into a large number of photovoltaic element modules having a size of 36 cm × 22 cm using a continuous modularization apparatus (not shown). Regarding the processed photovoltaic element module, an energy density of 100 mW /
When the characteristics were evaluated using simulated sunlight of cm ² ,
A photoelectric conversion efficiency of 7.8% or more was obtained, and the variation in characteristics among the photovoltaic element modules was within 5%. In addition, two of the processed photovoltaic element modules were extracted and subjected to a continuous bending test of 200 times. The characteristics did not deteriorate even after the test, and phenomena such as peeling of the deposited film were observed. I couldn't. Furthermore, the energy density of 100 mW /
Even after irradiation with 500 cm ² of pseudo sunlight for 500 hours, the photoelectric conversion efficiency was within 8.5% of the initial value. By connecting this photovoltaic element module, a power supply system with an output of 5 kW could be constructed. Further, the relationship between the elapsed time of film formation and the temperature of the wall of the deposition chamber is shown by a circle in FIG. FIG. 5 shows that the deposition chamber wall temperature is stable at 250 ° C. for a long time. FIG. 6D shows the relationship between the elapsed time of film formation and the obtained photoelectric conversion efficiency of the photovoltaic element module. FIG. 6 shows that the photoelectric conversion efficiency is stable at about 7.8% even when the film is formed for a long time.

[0043]

[Table 3] (Comparative Example 4) In this example, a photovoltaic element was manufactured in the same manner as in Example 4 except for the manufacturing conditions of the i-type semiconductor layer. Hereinafter, differences from the first embodiment will be summarized. (1) The same conditions were used except that the gas manifold was formed with an apparatus integrated with the deposited film wall without water cooling of the i-type semiconductor layer deposited film wall. As in the case of Example 4, changes over time in the deposition chamber wall temperature and the photoelectric conversion efficiency in accordance with the elapsed time of film formation are shown in FIG. FIG.
From FIG. 6, it can be seen that several hours after the start of film formation, the temperature of the deposition chamber wall exceeds the suitable temperature range, and the photoelectric conversion efficiency also sharply decreases.

[Embodiment 5] Although the a-Si: H deposited film is used as the p-type semiconductor layer in the above-described fourth embodiment, a-SiC: H is used instead of the a-Si: H deposited film. A photovoltaic element was manufactured using the deposited film and processed into a photovoltaic element module. Table 4 shows the manufacturing conditions. When the same characteristics as in Example 3 were evaluated for the processed photovoltaic element modules, a photoelectric conversion efficiency of 7.8% or more was obtained, and the variation in the characteristics between the photovoltaic element modules was 5%. Within. Further, even after the continuous bending test of 200 times, no deterioration of the characteristics was observed, and no peeling of the deposited film occurred. Furthermore, even after the continuous 500 hours of pseudo-sunlight irradiation, the variation in photoelectric conversion efficiency was within 8.3% of the initial value. By using this photovoltaic element module, a power supply system with an output of 5 kW could be configured.

[0045]

[Table 4]

[0046]

As described above, according to the present invention,
A non-single-crystal semiconductor thin film having high quality and excellent uniformity over a large area over a substrate can be formed. Further, according to the present invention, it is possible to manufacture a photovoltaic element with less photodegradation.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram for producing an i-type semiconductor layer of a non-single-crystal silicon photovoltaic device according to the present invention.

FIG. 2 is a schematic configuration diagram for explaining a layer configuration of a non-single-crystal silicon photovoltaic device according to the present invention.

FIG. 3 is a schematic configuration diagram for explaining a layer configuration of a stacked photovoltaic device of a non-single-crystal silicon photovoltaic device according to the present invention.

FIG. 4 is a schematic diagram of the photovoltaic device manufacturing apparatus according to the first embodiment.

FIG. 5 is a graph showing a relationship between a deposition chamber wall temperature and a film forming elapsed time according to Example 4 and Comparative Example 4.

FIG. 6 is a graph showing the relationship between the photoelectric conversion efficiency and the elapsed film formation time according to Example 4 and Comparative Example 4.

[Explanation of symbols]

 101: strip-shaped substrate 102: film deposition chamber 103: film deposition chamber wall 104: cooling pipe 105: gas manifold 106: deposition gas introduction pipe 106a: branch pipe 107: exhaust pipe 108: gate valve 109: oil diffusion pump 110: crude Pulling pipe 110a: L-shaped valve 111: i-layer deposition container (i-type semiconductor layer deposition container) 112: alumina ceramics 113: applicator 114: waveguide 115: lamp house 116: infrared lamp heater 117: thermocouple 118: bias rod 119: wall heater 201: substrate 202: back electrode 203: n-type semiconductor layer 204: i-type semiconductor layer 205: p-type semiconductor layer 206: transparent electrode 207: current collecting electrode 301: substrate 302: back electrode 303: n-type semiconductor layer 304: i-type semiconductor layer 305: p-type semiconductor layer 306: Type semiconductor layer 308: i-type semiconductor layer 309: p-type semiconductor layer 310: n-type semiconductor layer 311: i-type semiconductor layer 312: p-type semiconductor layer 313: transparent electrode 314: current collecting electrode 401: band-shaped substrate 402: delivery chamber 403: winding chamber 404: container for forming an n-type semiconductor layer 405: container for forming an i-type semiconductor layer 406: container for forming a p-type semiconductor layer 407: bobbin for sending out 408: bobbin for winding 409: conveying roller 410: Film formation gas inlet 411: Throttle valve for conductance adjustment 412: Exhaust pipe 413: Applicator 414: Waveguide 415: Electrode 416: Power supply 417: Lamp heater 418: Lamp house 419: Thermocouple 420: Gate gas inlet pipe 421 ： Wall cooling pipe 422 ： Gas manifold

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuzo Koda 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Takahiro Yajima 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inside the corporation

Claims (14)

[Claims] 1. A film deposition chamber having a film deposition space surrounded by a film deposition chamber wall and a strip-shaped substrate, and an outer chamber surrounding the deposition chamber wall, wherein the strip-shaped substrate is moved in a longitudinal direction of the strip-shaped substrate. While introducing the film-forming gas into the film-forming space through the gas supply means, and radiating microwave energy to the film-forming space by the microwave applicator means to generate microwave plasma, An apparatus for forming a non-single-crystal semiconductor thin film on a surface, wherein a cooling mechanism and a temperature raising mechanism are provided so as to cover a part of an outer surface of the deposition chamber wall. 2. The cooling mechanism and the temperature raising mechanism, wherein an outer surface of the film deposition chamber comprises a strip-shaped substrate surface, an applicator surface having the applicator means, an exhaust surface having gas exhaust means, and other normal surfaces. 2. The apparatus for forming a non-single-crystal semiconductor thin film according to claim 1, wherein the device is provided on the applicator surface or the normal surface. 3. The apparatus for forming a non-single-crystal semiconductor thin film according to claim 1, wherein said gas supply means includes a gas manifold, and said gas manifold is provided apart from said film forming chamber wall. 4. A film deposition chamber having a film deposition space surrounded by a film deposition chamber wall and a strip-shaped substrate, and an outer chamber surrounding the deposition chamber wall, wherein the strip-shaped substrate is moved in a longitudinal direction of the strip-shaped substrate. While introducing a film-forming gas into the film-forming space via a gas supply means while generating plasma in the film-forming space, and forming a non-single-crystal semiconductor thin film on the surface of the belt-like substrate, An apparatus for forming a non-single-crystal semiconductor thin film, wherein a gas supply means includes a gas manifold, and the gas manifold is provided apart from the film forming chamber wall. 5. An apparatus for forming a non-single-crystal semiconductor thin film according to claim 4, wherein a cooling mechanism and a temperature raising mechanism are provided so as to cover a part of the outer surface of said deposition chamber wall. 6. A microwave or VHF is provided in said film forming space.
The apparatus for forming a non-single-crystal semiconductor thin film according to claim 4, further comprising means for introducing a wave. 7. A semiconductor thin film forming apparatus comprising a film deposition chamber having a film deposition space surrounded by a film deposition chamber wall and a strip-shaped substrate, and an outer chamber surrounding the deposition chamber wall, wherein the strip-shaped substrate is formed in the strip shape. While moving in the longitudinal direction of the substrate, a film forming gas is introduced into the film forming space through a gas supply unit, and microwave energy is emitted to the film forming space by a microwave applicator unit to generate microwave plasma. In the method of forming a non-single-crystal semiconductor thin film on the surface of the strip-shaped substrate, the thin film is formed while controlling the temperature by a cooling mechanism and a temperature raising mechanism provided so as to cover a part of the outer surface of the deposition chamber wall. A method for forming a non-single-crystal semiconductor thin film. 8. The cooling mechanism and the temperature raising mechanism, wherein an outer surface of the film deposition chamber comprises a strip-shaped substrate surface, an applicator surface having the applicator means, an exhaust surface having gas exhaust means, and other normal surfaces. 8. The method for forming a non-single-crystal semiconductor thin film according to claim 7, wherein is provided on the applicator surface or the normal surface. 9. The method for forming a non-single-crystal semiconductor thin film according to claim 7, wherein said gas supply means includes a gas manifold, and said gas manifold is provided apart from said film forming chamber wall. 10. A semiconductor thin film forming apparatus comprising: a film deposition chamber having a film deposition space surrounded by a film deposition chamber wall and a band-shaped substrate; and an outer chamber surrounding the deposition chamber wall. While moving the film in the longitudinal direction of the substrate, a film-forming gas is introduced into the film-forming space via gas supply means,
In the method of generating plasma in the film forming space and forming a non-single-crystal semiconductor thin film on the surface of the band-shaped substrate, the gas supply unit includes a gas manifold, and the gas manifold is provided apart from the film forming chamber wall. A method for forming a non-single-crystal semiconductor thin film. 11. The non-single-crystal semiconductor according to claim 10, wherein the thin film is formed while controlling the temperature by a cooling mechanism and a temperature raising mechanism provided so as to cover a part of the outer surface of the deposition chamber wall. A method for forming a thin film. 12. A microwave or VH is provided in said film forming space.
2. The apparatus according to claim 1, further comprising means for introducing an F wave.
0. The method for forming a non-single-crystal semiconductor thin film according to item 0. 13. A method for manufacturing a photovoltaic device, comprising the step of forming a non-single-crystal semiconductor thin film using the method according to claim 7. Description: 14. The method according to claim 13, wherein the step of forming the non-single-crystal semiconductor thin film is a step of forming an i-type semiconductor layer.