JPH06204540A - Photovoltaic element - Google Patents

Abstract

PURPOSE:To improve the sensitivity to a long wavelength, to suppress optical deterioration and to improve an afterimage characteristic by a method wherein a (p) layer, an (i) layer and an (n) layer are laminated on a substrate, the (i) layer is formed by a method wherein a radical containing germanium or silicon is made to react in a prescribed region, and the (i) layer is made to contain microcrystal germanium having a specified particle size. CONSTITUTION:An (c) layer 102 constituted of an amorphous silicon semiconductor containing hydrogen, an (i) layer 103 and a (p) layer 104, and a transparent electrode 105 and a collector electrode 106, are laminated on a substrate 101. The (i) layer 103 is formed by a microwave plasma CVD method in a state wherein a region of plasma produced by applying a microwave to a gas containing germanium and a region of plasma produced by applying the microwave to a gas containing silicon are isolated from each other. A radical thus produced and containing the germanium and a radical thus produced and containing the silicon are made to react in am prescribed different regions. Besides, the (i) layer 103 contains microcrystal germanium of a particle size 50 to 500Angstrom .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The photovoltaic element of the present invention relates to an electronic element to which a photovoltaic effect is applied, such as a solar cell and a photo sensor. Solar cells are used as components for solar power generation systems, calculators, night indicator lights, etc. Also, photo sensors are facsimiles, image scanners, factory automation (FA).
It is used as a component of equipment.

In particular, the present invention relates to a pin type photovoltaic element made of an amorphous silicon semiconductor. The present invention also relates to a photovoltaic element containing microcrystalline germanium. The present invention also relates to a photovoltaic element in which the doping layers (p layer and n layer) and i layer are formed by the microwave plasma CVD method (MWPCVD method).

[0003]

2. Description of the Related Art Recently, studies have been made on the use of amorphous silicon semiconductors as photovoltaic elements. For example, an amorphous silicon (a-Si) solar cell can use an a-Si layer as a photovoltaic layer to efficiently convert light into electric power. Further, in a photosensor using an a-Si layer as a photovoltaic layer, the photosensitivity of a-Si is applied so as to be very close to the sensitivity of human eyes.

In recent years, studies have been made on the use of amorphous silicon germanium (a-SiGe) as a photovoltaic element. For example, a-SiGe solar cell is a-S
The iGe layer can be used as a photovoltaic layer to efficiently convert light having a long wavelength into electric power. Further, a photosensor using the a-SiGe layer as a photovoltaic layer is excellent in detecting long-wavelength light.

However, it was found by Raman scattering, electron diffraction, and high resolution electron microscope observation that the photovoltaic layer of the photovoltaic element of the present invention is different from a-SiGe. In addition, conventionally, microcrystalline germanium (mc-Ge)
Is used in temperature sensors, optical power sensors, infrared light sensors, etc. that apply the thermoelectromotive force effect. For example, ◆ “A high‐accuracy quick‐response optical power
sensor with μc-Ge: H thin film. Kodato S. Naito Y. Kuroda K. Kodama S Sens Actuators A. Vol 28, No.1, pp.63-68 ◆ Thermoelectric properties of microcrystalline germanium thin film and application to sensor Examples include materials such as Etsunobu Naito, Yasuji Uchida, Kazuo Mizuno, and Setsuo Furuta.

However, it can be said that there is no example in which the photovoltaic layer contains mc-Ge and is used as a photovoltaic element.
Moreover, such researches are few and the quality is low for application to the photovoltaic device. In addition, MWPCV has a high deposition rate and excellent source gas utilization efficiency.
Photovoltaic devices using the D method have been studied. For example, as an example of forming the i layer by the MWPCVD method, ◆ “a-Si solar cell by microwave plasma CVD method” Kazufumi Higashi, Takeshi Watanabe, Toshikazu Shimada Proceedings of the 50th Annual Meeting of the Applied Physics Society pp. 566 etc. are fisted. In this photovoltaic element, i layer is MWPC
By forming by the VD method, a good quality i layer having a high deposition rate is obtained.

An example of forming the doping layer by the MWPCVD method is, for example, "High Efficiency Amorphous Solar Cell Employing".
ECR‐CVD Produced p‐Type Microcrystalline SiC Fi
lm "Y.Hattori, D.Kruangam, T.Toyama, H.0kamoto and Y.Hama
kawa Proceedings of the International PVSEC-3 Tokyo Ja
pan l987 pp.171 ◆ “HIGH-CONDUCTIVE WIDE BAND GAP P ー TYPE a‐SiC: H
PREPARED BY ECR CVDAND ITS APPLICATION TO HIGH EF
FICIENCY a‐Si BASIS SOLAR CELLS "Y.Hattori, D.Kruangam, K.Katou, Y.Nitta, H.0kamoto and
Y.Hamakawa Proceedings of 19th IEEE Photovoltaic Specialists
Conference l987 pp.689, etc. In these photovoltaic elements, the MW is formed in the p layer.
A high quality p layer is obtained by using the PCVD method.

However, in these examples, mc-Ge is not mentioned.

[0009]

In the above a-Si solar cell, the a-Si layer can be used as a photovoltaic layer to efficiently convert light into electric power, but the long wavelength sensitivity is low. There was a point. Further, when the a-SiGe layer is used as the photovoltaic layer, long-wavelength sensitivity is improved, but photodegradation (deterioration of device characteristics when the photovoltaic device is irradiated with light for a long time) becomes a problem. Further, the afterimage is a problem in the photosensor using the a-SiGe layer as the photovoltaic layer.

An object of the present invention is to provide a photovoltaic element that solves the above-mentioned conventional problems. That is, it is an object of the present invention to provide a solar cell having improved long-wavelength sensitivity and suppressed photodegradation. Another object is to provide a photo sensor with improved afterimage characteristics. Moreover, it aims at providing the photovoltaic element which improved the temperature characteristic.

[0011]

DISCLOSURE OF THE INVENTION The present invention has been found as a result of extensive studies to solve the conventional problems and achieve the above-mentioned object, and the photovoltaic device of the present invention comprises: P made of an amorphous silicon semiconductor containing hydrogen
In a photovoltaic device in which a layer, an i layer, and an n layer are laminated on a substrate, and the i layer is formed by a microwave plasma CVD method, the i layer is generated by irradiating a gas containing germanium with microwaves. The plasma region (A) is separated from the plasma region (B) generated by irradiating the silicon-containing gas with microwaves, and the germanium-containing radical R _ge generated in the region (A) is separated. The silicon-containing radical R _si generated in the region (B) is formed by a reaction in a region (C) different from the region (A), and the i layer contains microcrystalline germanium, and the microcrystalline germanium is formed. Is characterized by having a particle size of 50 to 500Å.

A preferred embodiment of the present invention is the territory described above.
(C) is a p-layer, i-layer, or n-layer surface
It is the above-mentioned small photovoltaic element. Furthermore, the present invention
A desirable form of the p-layer and / or the n-layer is germanium.
It was generated by irradiating microwave containing gas with um
In the plasma area (AA) and the gas containing silicon
A region of plasma (B
B) is separated and germanium produced in the area (AA)
Radical containing R _geAnd the area generated in the area (BB)
Radical R containing recon_SiIs different from the area (AA)
Formed in the region (CC) of the
It contains rumanium and the grain size of the microcrystalline germanium is 5
The above photovoltaic element, characterized in that it is 0 to 500Å
Is a child.

Furthermore, a desirable mode of the present invention is the photovoltaic element as described above, wherein the region (CC) is a substrate or an i-layer surface. Still further, in a preferred embodiment of the present invention, the i-layer contains microcrystalline silicon,
In the above photovoltaic element, the grain size of the microcrystalline silicon is 50 to 500 Å.

Furthermore, in a preferred embodiment of the present invention, the p-layer and / or the n-layer contains microcrystalline silicon, and the grain size of the microcrystalline silicon is 50 to 500 Å. It is a power device.

[0015]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic explanatory view of the photovoltaic element of the present invention
n-type. In FIG. 1, the photovoltaic device of the present invention comprises a substrate 101, an n layer (or p layer) 102, and an i layer 10.
3, a p layer (or an n layer) 104, a transparent electrode 105, a collector electrode 106, and the like.

FIG. 2 is a schematic explanatory view of another example of the photovoltaic element of the present invention, which is of the pinpin type. In FIG. 2, the photovoltaic element of the present invention is a substrate 111, an n1 layer (p
1 layer) 112, i1 layer 113, p1 layer (n1 layer) 11
4, n2 (p2 layer) layer 115, i2 layer 116, p2 (n
(Two layers) layer 117, transparent electrode 118, and collector electrode 119
Etc.

FIG. 3 is a schematic explanatory view of another example of the photovoltaic element of the present invention, which is of the pinpinpin type. In FIG. 3, the photovoltaic element of the present invention is the substrate 121, n1.
Layer (p1 layer) 122, i1 layer 123, p1 layer (n1 layer)
124, n2 layer (p2 layer) 125, i2 layer 126, p2
The layer (n2 layer) 127, the n3 layer (p3 layer) 128, the 13 layer 129, the p3 layer (n3 layer) 130, the transparent electrode 131, the collector electrode 1 and the like 2.

FIG. 4 is a schematic explanatory view of another example of the photovoltaic element of the present invention, which is of a pinpin type, and is a pinpin.
The light reflection layer 142 and the transparent conductive layer 143 each having an uneven surface are provided below the layer. In FIG. 4, the photovoltaic device of the present invention comprises a support 142, a light reflection layer 143, a transparent conductive layer 144 (the substrates 142, 143, 144 are collectively referred to as a substrate 141), an n1 layer (p1 layer) 145, an i1 layer. 14
6, p1 layer (n1 layer) 147, n2 layer (p2 layer) 14
8, an i2 layer 149, a p2 layer (n2 layer) 150, a transparent electrode 151, a collector electrode 152, and the like.

Further, in addition to the photovoltaic element having the pin structure as shown in FIG. 1, a nip in which the stacking order of the n layer and the p layer is reversed.
It may be a photovoltaic device having a mold structure. Furthermore, in the photovoltaic element of the pinpin type structure as shown in FIG. 2, the photovoltaic element of the nipnip type structure in which the stacking order of the n layer and the p layer is reversed may be used. Furthermore, pinp as shown in Fig. 3
In the photovoltaic device of the inpin type structure, a photovoltaic device of the nipnipnip type structure in which the stacking order of the n layer and the p layer is reversed may be used.

Further, in the photovoltaic element of the pinpin type structure as shown in FIG. 4, the photovoltaic element of the nipnip type structure in which the stacking order of the n layer and the p layer is reversed may be used.
Furthermore, in FIGS. 1 to 4, the i layer may be composed of a plurality of layers having different properties. For example, a layer formed by the RF plasma CVD method (RF-i layer) and an i layer formed by the microwave plasma CVD method (MW-i layer)
A, a i-layer made of a-Si and a-Si,
It may be a stack of i layers made of a-SiC, a-SiN, or the like. Further, a transition layer may be provided between the p layer and the i layer and between the n layer and the i layer. By providing the transition layer, each layer can be continuously formed.

The photovoltaic layer (i) of the photovoltaic device of the present invention
It is considered that the layer) is divided into a region that absorbs light and a region that transports the generated photocarriers. The former region is a region in which microcrystalline germanium is present, and the latter region is composed of a non-single crystal silicon semiconductor. It is an area where It is considered that these regions are bonded by a semiconductor junction, the interface thereof is good, and the interface state is extremely small.

Since the photovoltaic element of the present invention contains microcrystalline germanium in the i layer made of a non-single crystal silicon semiconductor, it absorbs light having a long wavelength (800 nm to 1500 nm) and is generated as a photocarrier. Are separated into electrons and holes by an electric field inside the i layer which is a photovoltaic layer, and electrons are efficiently transported to the n layer and holes to the p layer by this internal electrolysis. Therefore, the photovoltaic element of the present invention has a large short-circuit photocurrent (J _sc ) and the ratio of generated power to incident light energy (power) (photoelectric conversion efficiency) is 1.
It can be 0% or more. Such high photoelectric conversion efficiency (η) is an important characteristic element for photovoltaic devices such as solar cells.

In the photovoltaic element of the present invention (claim 7), the content of microcrystalline germanium in the i layer changes smoothly in the layer thickness direction. By doing so, the photoelectric conversion efficiency is improved. That is, for example, as shown in FIG. 8 (a), the p-layer side inside the bulk is where the microcrystalline germanium content is reduced on the p-layer side and the n-layer side of the i-layer and the microcrystalline germanium content is maximized. Figure 9
As shown in (a), the band gap of the i-layer becomes maximum on the p-layer side and the n-layer side, and the minimum value is on the p-layer side inside the bulk. Therefore, on the p-layer side of the i-layer, the electric field in the conduction band is large, so that the electrons and holes are efficiently separated, and
Recombination of electrons and holes near the interface between the layer and the i layer can be reduced. In addition, it is possible to prevent electrons from back-diffusing into the p-layer. Further, since the electric field in the valence band increases from the i layer to the n layer,
Recombination of electrons and holes excited on the layer side can be reduced.

Further, it is particularly effective when the heterojunction (Si / SiN, Si / SiC, etc.) is formed between the i layer and the doping layer. Generally, it is considered that many interface states and internal stress exist at the interface of the heterojunction. In the photovoltaic device of the present invention, by containing a small amount of microcrystalline germanium in the vicinity of the interface of the heterojunction, the interface state can be reduced and the internal stress can be relaxed. Therefore, the characteristics of the device are less likely to deteriorate even in a vibrating environment.

It is generally known that increasing the content of microcrystalline germanium in the i-layer made of a non-single crystal silicon semiconductor reduces the band gap. Hereinafter, with reference to the drawings, an example of a desirable change pattern of the microcrystalline germanium content of the i layer in the photovoltaic device of the present invention, which is considered from the change of the band gap in the layer thickness direction, will be described.

FIG. 8A shows an example in which the microcrystalline germanium content is drastically changed on the p-layer side as described above, and the minimum content is on the p-layer side inside the bulk. in this case,
The band gap is as shown in FIG. 9A, and when light is incident from the p-layer side, the high electric field near the interface between the p-layer and the i-layer and the high electric field near the interface between the n-layer and the i-layer are more effective. It is possible to improve the collection efficiency of electrons and holes photoexcited in the i layer. Further, in the case of making light incident from the n-layer side in the nip type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction. Further, when the band gap of the i layer is small, it is particularly effective. Also p /
It is particularly effective when the i interface is formed by heterojunction.

FIG. 8B shows an example in which the p-layer side is slowly changed to the n-layer side, and the minimum content is at the interface with the n-layer. In this case, the band gap becomes as shown in FIG. 9B, the electric field of the valence band can be increased over the entire region of the i layer, the carrier range for holes can be particularly improved, and the fill factor can be increased. Can be improved. When light is incident from the n layer side in the nip type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction. Further, when the band gap of the i layer is small, it is particularly effective.

FIG. 8C shows an example in which the content of microcrystalline germanium changes rapidly on the p-layer side and the n-layer side of the i layer. In this case, the band gap is as shown in FIG. 9C, and the electric field of the conduction band can be increased on the p-layer side of the i-layer, and in particular, the reverse diffusion of the lightning element to the p-layer can be suppressed. . Further, the electric field in the valence band can be strengthened on the i layer and n layer sides, and in particular, the back diffusion of holes into the n layer can be suppressed. Further, the microcrystalline germanium content as shown in FIG. 8C and the bandgap change pattern as shown in FIG. 9C are particularly effective for a photovoltaic device having an i layer having a large bandgap. That is, when light is incident from the p-layer side in FIG. 9C, the i-layer having a large bandgap cannot sufficiently absorb the light, and photoexcited carriers near the interface between the i-layer and the n-layer do not recombine. The strong electric field in the vicinity of this interface separates them, and collection efficiency can be improved. Further, it is effective for a photovoltaic element having a light reflecting layer. That is, in a photovoltaic device having a light reflection layer, light is incident on the i-layer from both layers, so that collection efficiency can be similarly increased. With the above configuration, the carrier range can be improved and the fill factor can be improved. It is particularly effective when the p / i interface and the n / i interface are heterojunctions.

In a photovoltaic element that uses a-SiGe for the photovoltaic layer and absorbs light of long wavelength (800 nm to 1000 nm), the open-circuit voltage (V _oc ) is low because the band gap of a-SiGe is small. Fill factor (FF)
However, in the photovoltaic element of the present invention, since the i-layer made of the non-single-crystal silicon semiconductor contains microcrystalline germanium, the open circuit voltage is large and the photoelectric conversion efficiency is high. Can be improved. Further, in the present invention, since the base material is a non-single crystal silicon semiconductor, the fill factor is improved more than a-SiGe, and the photoelectric conversion efficiency can be improved. Further, in the photosensor, it is necessary to apply an electric field to the photovoltaic layer from the outside and quickly inject the generated photocarriers into the electrodes (improve the photoresponse), and it is important to improve the fill factor.

In the photosensor, if the photovoltaic layer or the doping layer has a deep level, the photocarriers generated may be trapped and thermally excited as carriers again. In the photosensor, the above-mentioned thermally-excited carrier afterimage appears, but the photosensor using the photovoltaic element of the present invention has few deep levels and prevents the afterimage phenomenon.

The photovoltaic element of the present invention has improved temperature characteristics. That is, since the above-mentioned thermally excited carriers are reduced, the influence of temperature is suppressed as compared with the conventional one. Therefore, the range of operating environment temperature is widened, and the rise time of the device using the photovoltaic element is shortened. Further, in the photovoltaic device of the present invention, when microcrystalline germanium is contained in the doping layer (n layer and / or p layer), it becomes superior to the conventional doping layer using a-SiGe. That is, when a-SiGe is used for the doping layer in the solar cell, there is a problem that the carrier concentration is low and the open circuit voltage is low, but in the photovoltaic device of the present invention, the doping layer is made of a non-single crystal silicon semiconductor Since the base material contains the above-described microcrystalline germanium, the carrier concentration is high, and therefore the open circuit voltage of the photovoltaic element can be increased and the photoelectric conversion efficiency can be improved.

Also, photodegradation can be suppressed by containing microcrystalline silicon (mc-Si). The microcrystalline silicon region, the microcrystalline germanium region, and the other region are in contact with each other by a semiconductor junction, and the interface state is small. When microcrystalline silicon is contained in the doping layer, the carrier concentration can be further improved, so that the open circuit voltage of the photovoltaic element can be improved. Further, since the visible light transmittance can be improved, it is effective as a doping layer of a photovoltaic element.

Further, in the present invention, the microcrystalline silicon content in the i layer changes in the layer thickness direction, and the position where the content is the minimum is between the central position of the i layer and the p layer. Furthermore, the photoelectric conversion efficiency can be improved. That is, the defect level can be reduced by reducing the microcrystalline silicon content in the region where the microcrystalline germanium content is high. Further, by including a large amount in the vicinity of the interface with the doping layer, the open circuit voltage can be improved. Therefore, for the change in the content of microcrystalline germanium as shown in FIG. 8A, the change in the content of microcrystalline silicon as shown in FIG. 10A is desirable.

Similarly, with respect to the change in the content of microcrystalline germanium as shown in FIG. 8 (b), the change in the content of microcrystalline silicon as shown in FIG. 10 (a) is desirable, and as shown in FIG. 8 (c). FIG. 10 shows changes in the content of microcrystalline germanium.
The change in the content of microcrystalline silicon as shown in (c) is desirable. Further, when the doping layer is made of microcrystalline silicon, internal strain and the like are alleviated, and the characteristics are less likely to deteriorate even in an environment with vibration.

Floating zone (FD) method, Czochralski (CZ) method and ribbon pulling method have been known as methods for producing crystalline germanium.
As a method for forming the thin film crystalline germanium on the substrate, RF plasma CVD method (RFPCVD method), optical CV
D method, thermal CVD method, sputtering method and the like can be mentioned. In each case, the substrate temperature is 700 to 900 ° C. or the thin film formed at the substrate temperature 100 to 300 ° C. is annealed at the substrate temperature 600 to 800 ° C. Or a thin film formed at a substrate temperature of 100 to 300 ° C. is thermally annealed using a laser or the like. In any of these methods, the temperature of the substrate becomes high, so that a substrate made of an inexpensive material such as stainless steel cannot be used. Further, in these methods, the temperature is too high to contain microcrystalline germanium in the amorphous silicon semiconductor layer as in the present invention, and a good quality amorphous silicon semiconductor layer cannot be obtained. However, if the method for forming the semiconductor layer of the photovoltaic element of the present invention is used, a good quality amorphous silicon semiconductor layer containing microcrystalline germanium can be formed at a relatively low temperature. That is, the MWPCVD method has the following features.

(1) A region (A) of plasma generated by irradiating a gas containing germanium (eg GeH ₄ gas) with microwaves and a region containing silicon (eg SiH ₄ ) are irradiated with microwaves. The region (B) of the plasma generated by the above is separated, and the radical R _g containing germanium generated in the region (A) and the radical R _S containing silicon generated in the region (B) are separated into the region (A). ) And a different region (in the gas phase).

(2) The radical R _ge and the radical R _Si are reacted on the substrate surface (semiconductor layer surface). In order to change the microcrystalline germanium content in the layer thickness direction by such a method, it is preferable to change the flow rate of the source gas containing germanium with time. When the semiconductor layer is formed by the roll-to-roll method, it is preferable to spatially change the germanium-containing radicals incident on the substrate surface.

According to these methods, germanium can be crystallized at a temperature lower than the conventional substrate temperature, and the selection range of the substrate material is widened. Suitable substrate temperature is 20
It is 0-400 degreeC. Further, the radical R _g containing germanium in the region (A) is already a germanium cluster having crystallinity, and it is considered that MWPCVD can easily generate a germanium cluster having crystallinity in the vapor phase. In these methods, the pressure in the plasma region (A) is set to 50 mTorr or more to shorten the mean free path and activate the gas phase reaction between radicals. In the method (1), the pressure in the plasma region (B) is preferably set to 50 mTorr or more to activate the gas phase reaction of the germanium cluster and the radical R _S containing silicon. Further, in the method (2), it is desirable to set the pressure to 30 mTorr or less to suppress reaction of the germanium cluster and R _S in the gas phase as much as possible.

In addition to the microcrystalline germanium,
When a recon is contained, the following method can be mentioned. (I) Source gas containing fluorine (eg SiF_Four, S
i₂F₆, GeF_Four, BF ₃Substrate temperature to 300
It is formed by introducing a high MW power at ˜600 ° C.

In order to change the microcrystalline silicon content in the layer thickness direction by such a method, the flow rate of the raw material gas containing fluorine may be changed with time. It was confirmed by Raman scattering, electron diffraction, and high-resolution electron microscope observation that the deposited film formed by such a method contained microcrystalline germanium. The Raman shift of Raman scattering shows a broad peak near 480 cm ^-1 corresponding to amorphous silicon and 300 cm ^-1 corresponding to microcrystalline germanium.
A sharp peak was seen in the vicinity. Furthermore, a sharp ring was observed in the broad ring by electron diffraction.
In addition, white microscopic regions corresponding to microcrystalline germanium were observed in the dark field image of high resolution electron microscope observation. Further, in the sample under the forming condition (I), the wave number corresponding to microcrystalline silicon is 5
A Raman shift with a sharp peak at 20 cm ^-1 was observed.

In the present invention, the desirable crystal grain size of the microcrystalline germanium is 50 to 500 Å, and if it is smaller than 50 Å, the influence of the crystal grain boundary appears, and if it is larger than 500 Å, the dark current increases and it is close to that of crystal germanium. Since it may have properties, it is preferably 500 Å or less from the viewpoint of being contained in the pin layer of the photovoltaic element. In the present invention, the desirable crystal grain size of microcrystalline silicon is 50 to 500.
If it is less than 50 Å, the shadow of the crystal grain boundary appears, and if it is more than 500 Å, dark current increases and it has properties close to crystalline silicon.
From the viewpoint of being contained in the in layer, it is preferably 500 Å or less.

In the present invention, the microcrystalline germanium may contain hydrogen (or deuterium) and / or fluorine. The content of each is 0.01 to 10%, preferably 0.01 to 5%. In the present invention, the microcrystalline silicon may contain hydrogen (or deuterium) and / or fluorine. Each content is 0.01-10%
And preferably 0.01 to 5%.

FIG. 5 is a schematic explanatory view of a deposition apparatus suitable for forming the semiconductor layer of the photovoltaic element of the present invention. This deposition apparatus 200 includes a deposition chamber 201, a vacuum gauge 202, a bias power source 203, a substrate 204, a heater 205, a waveguide 206, a conductance valve 207, a valve 208,
Bias electrode 210, gas introduction pipe 211, applicator 212, dielectric window 213, substrate shutter 215, microwave power supply 219, exhaust gas 220, gas introduction pipe 22.
1. A vacuum exhaust pump (not shown) connected to the exhaust gas outlet, a source gas supply device connected to the gas introduction pipe, and the like. The raw material gas supply device (not shown) includes a raw material gas cylinder, a valve, a mass flow controller and the like. The dielectric window 213 is made of, for example, alumina ceramics (Al
₂ O ₃ ), quartz, boron nitride and the like, which are well permeable to microwaves and can separate atmospheric pressure and vacuum. Further, a plasma region (A) generated by irradiating a germanium-containing gas with a microwave and a plasma region (B) generated by irradiating a silicon-containing gas with a microwave are shown in FIG. Separate.

The photovoltaic element of the present invention is manufactured as follows. First, the substrate 204 is brought into close contact with the heater 205 installed in the deposition chamber 201 of FIG. 5, and the inside of the deposition chamber is sufficiently evacuated to 1 × 10 ⁻⁵ Torr or less. A turbo molecular pump or an oil diffusion pump is suitable for this exhaust. After exhausting the inside of the deposition chamber sufficiently, H ₂ , H
Gases such as e and Ar are introduced into the deposition chamber so that the pressure in the deposition chamber is almost the same as when the source gas for forming the semiconductor layer is flown, and the heater 205 is turned on to heat the substrate. When the temperature of the substrate stabilizes at a predetermined temperature, a predetermined amount of a raw material gas for semiconductor layer formation is introduced into the deposition chamber from a gas cylinder via a mass flow controller.

The supply amount of the source gas for forming the semiconductor layer, which is introduced into the deposition chamber, is appropriately determined according to the volume of the deposition chamber and the desired deposition rate. MWP semiconductor layer
When forming by the CVD method, the pressure during the formation of the semiconductor layer is a very important factor. In the case of the method (1), it is 50 to 5 in the plasma region (A).
00 mTorr, 50 to 300 in plasma region (B)
mTorr is preferred.

In the case of the method (2), the plasma region (A)
Is preferably 50 to 500 mTorr and the plasma region (B) is preferably 0.5 to 30 mTorr. Also, the MW power introduced into each plasma region is an important factor. The MW power is appropriately determined depending on the flow rate of the raw material gas introduced into the plasma region, but a preferable range is 100 to 2000 W. A preferable frequency range of the MW power is 0.5 to 10 GHz, and a frequency around 2.45 GHz is particularly suitable.
The MW power generated from such a microwave power source 219 is transmitted through the waveguide 206, introduced from the applicator 212 into the deposition chamber through the dielectric window 213, each plasma is generated, the shutter is opened, and the substrate is opened. A semiconductor layer having a desired layer thickness is formed thereover. After that, the introduction of MW power was stopped, the plasma was extinguished, the deposition chamber was evacuated,
After sufficiently purging with a gas such as H ₂ , He or Ar, the substrate is taken out from the deposition chamber.

When forming the i layer of the photovoltaic element of the present invention, RF power may be applied to the bias electrode 210 together with MW power. In this case, the MW power to be introduced is the MW required to decompose 100% of the source gas introduced into the deposition chamber.
The power is preferably smaller than the power, and the RF power introduced at the same time is preferably larger than the MW power. A preferable range of RF power to be simultaneously introduced is 100 to 2000 W. A preferable frequency range of the RF power is 1 to 100 MHz. Particularly, 13.56 MHz is optimum. Especially when the area of the RF electrode for supplying RF power is smaller than the area of ground,
It is better to ground the self-bias (DC component) on the power supply side for power supply. Also, the bias electrode is RF
A DC voltage may be applied together with electric power. A preferable range of the DC voltage is about 30 to 300V.

When the p layer and the n layer are formed by the RFPCVD method, the capacitive coupling type RFPCVD method is suitable. RF power is applied to the bias electrode in FIG. When forming the i layer and the doping layer by the RFPCVD method, the substrate temperature in the deposition chamber is 100 to 500 ° C., and the pressure is 0.1 to 10 Tor.
r, RF power is 1 to 800 W, deposition rate is 0.1 to 2 n
The optimum condition is m / sec.

US Pat. No. 4,400,409 discloses a plasma CVD apparatus for continuously forming a semiconductor layer employing a roll-to-roll method.
It is desirable that the photovoltaic element of the present invention be continuously manufactured using such an apparatus. According to this apparatus, a plurality of deposition chambers are provided, a long and flexible substrate is arranged along a path through which the substrates sequentially pass through the deposition chamber, and the deposition chamber has a desired conductivity type. By continuously transporting the substrate in the longitudinal direction while forming the semiconductor layer, p
It is said that a photovoltaic device having an in-junction can be continuously manufactured. In this specification, a gas gate is used to prevent a source gas for containing each valence electron control agent in a semiconductor layer from diffusing into another deposition chamber and mixing into another semiconductor layer. ing. That is, the deposition chambers are separated from each other by a slit-shaped separation passage, and a scavenging gas such as Ar, H ₂ , or He is caused to flow into each separation passage to prevent mutual diffusion of the source gases. ..

The photovoltaic element of the present invention can be mass-produced by using the method of continuously forming the semiconductor layer as described above, and the manufacturing cost can be significantly reduced. In the method of forming a semiconductor layer by the MWPCVD method or the RFPCVD method, the following gas or a compound that can be gasified by bubbling is suitable as a source gas for containing each atom. Table 1 exemplifies the atoms and raw material gases to be contained.

[0051]

[Table 1] The valence electron control agent contained in order to make the conductivity type of the semiconductor layer p-type is an atom of group III (B, Al, G) of the periodic table.
a, In, Tl), and examples of the valence electron control agent to be contained in order to make the conductivity type n-type include a group V atom (P, As, Sb, Bi) and a group VI atom (S) of the periodic table. , Se, T
e) can be mentioned. Each is shown in Table 2.

[0052]

[Table 2] Further, the above raw material gas may be appropriately diluted with a gas such as H ₂ , D ₂ , He, Ar or the like and introduced into the deposition chamber.

(Substrate) The substrate may be composed of a conductive material alone, or a conductive layer formed on a support composed of an insulating material or a conductive material. As the conductive material, for example, NiCr, stainless steel, Al, Cr, Mo, Au, Nb, Ta, V, Ti,
Examples include metals such as Pt, Pb, and Sn, or alloys thereof. In order to use these materials as a support, it is desirable that the material be in the form of a sheet, a roll in which a long sheet is wound around a cylinder, or a cylinder.

As the insulating material, polyester, polyethylene, polycarbonate, cellulose acetate,
Examples thereof include synthetic resins such as polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene and polyamide, and glass, ceramics and paper. In order to use these materials as a support, it is desirable that the material be in the form of a sheet, a roll in which a long sheet is wound around a cylinder, or a cylinder. In these insulating supports, a conductive layer is formed on at least one surface thereof, and the semiconductor layer of the present invention is formed on the surface on which the conductive layer is formed.

For example, glass is NiC on the surface.
r, Al, Ag, Cr, Mo, Ir, Nb, Ta, V,
Ti, Pt, Pb, In ₂ O ₃ , ITO (In ₂ O ₃ + Sn
O ₂ ), ZnO, or other material or an alloy thereof is used to form a conductive layer, and a synthetic resin sheet such as polyester film has NiCr, Al, Ag, Pb, Zn, N on the surface.
i, Au, Cr, Mo, Ir, Nb, Ta, V, Ti,
Forming a conductive layer made of a material such as Pt or an alloy thereof,
For stainless steel, NiCr, Al, Ag, Cr, M
o, Ir, Nb, Ta, V, Ti, Pt, Pb, In ₂
A conductive layer made of a material such as O ₃ , ITO (In ₂ O ₃ + SnO ₂ ), ZnO or an alloy thereof is formed. Examples of the forming method include a vacuum vapor deposition method, a sputtering method, a screen printing method and the like.

The surface shape of the support is preferably smooth or uneven (textured) with a peak height of 0.1 to 1.0 μm at the maximum. For example, in order to make the surface of a stainless steel substrate uneven, there is a method in which a large number of glass balls having a diameter of 0.1 to 2.0 mm are slammed against the surface of the substrate. The thickness of the substrate is appropriately determined so that a desired photovoltaic element can be formed, but when flexibility as a photovoltaic element is required, it is within a range in which the function as a support is sufficiently exerted. It can be made as thin as possible. However, in view of mechanical strength and the like in terms of manufacturing and handling of the support, it is usually 10 μm or more.

The preferred substrate form in the photovoltaic element of the present invention is Ag, Al, Cu, A on the support.
This is to form a conductive layer (light reflection layer) made of a metal having a high reflectance in the near infrared from visible light such as 1Si. The light reflecting layer is suitably formed by a vacuum vapor deposition method, a sputtering method or the like. As a layer thickness of these metals as a light reflecting layer, a suitable layer thickness is 10 nm to 5000 nm. In order to texture the surface of the light reflection layer, the substrate temperature at the time of formation may be 200 ° C. or higher.

Further Desirability in Photovoltaic Device of the Present Invention
A preferable substrate form is ZnO, Sn on the light reflection layer.
O₂, In₂O₃, ITO, TiO₂, CdO, Cd₂Sn
O_Four, Bi ₂O₃, MoO₃, Na_xWO₃Transparent guide consisting of etc.
Forming an electric layer. As a method of forming a transparent conductive layer
Vacuum deposition, sputtering, CVD, play
Method, spin-on method, dipping method, etc.
Can be mentioned. Also, the layer thickness is optimal depending on the refractive index of the layer.
Layer thickness is different, but preferable layer thickness range is 50 nm
-10 micrometers is mentioned. Furthermore, the transparent conductive layer is textured.
The temperature of the substrate when the layer is formed is 2
It is preferable to raise the temperature to 00 ° C. or higher.

(Doping layer (p layer, n layer)) The base material of the doping layer is composed of an amorphous silicon semiconductor.
Amorphous (abbreviated as a-) silicon-based semiconductor is a
-Si, a-SiC, a-SiO, a-SiN, a-S
iCO, a-SiON, a-SiNC, a-SiCON
Etc.

Particularly, a crystalline semiconductor with little light absorption or an amorphous semiconductor layer with a wide band gap is suitable for the doping layer on the light incident side. Specifically, a-SiC, a-S
iO, a-SiNa-SiCO, a-SiON, a-S
iNC and a-SiCON are suitable. When microcrystalline germanium is contained, it is preferably formed by the above methods (1) and (2) using the MWPCVD method. I
When more light is incident on the layer, it is desirable that the doping layer on the light incident side does not contain microcrystalline germanium.

When microcrystalline silicon is included, the above M
It is desirable to form by the method (I) using the WPCVD method. Further, when more light is incident on the i layer, it is desirable that the doping layer on the light incident side contains a large amount of microcrystalline silicon. The amount of the valence electron control agent introduced to make the conductivity type p-type or n-type is 1000 ppm.
-10% is mentioned as a preferable range. Hydrogen (H,
D) and fluorine function to compensate dangling bonds and improve the doping efficiency. The optimum amount of hydrogen and fluorine is 0.1 to 30 at%. Especially when the doping layer contains microcrystalline germanium or microcrystalline silicon, the optimum amount is 0.01 to 10 at%. Introduced amount of carbon, oxygen and nitrogen atoms is 0.1p
pm ~ 20%, 0.1ppm when contained in a trace amount
-1% is a suitable range.

As electric characteristics, the activation energy is 0.
It is preferably 2 eV or less, and most preferably 0.1 eV or less. The specific resistance is preferably 1 OOΩcm or less, and most preferably 1Ωcm or less. In particular, when forming a crystalline semiconductor having a small light absorption or an amorphous semiconductor layer having a wide band gap as described above, the source gas is diluted 2 to 100 times with a gas such as H ₂ , D ₂ , and He, and the MWPCVD method is used. RFPCVD with relatively high MW power
When forming by a method, it is preferable to introduce a relatively high RF power.

(I layer) In the photovoltaic device of the present invention,
The i layer is the most important layer for generating and transporting photoexcited carriers. A slightly p-type or slightly n-type layer can be used as the base material of the i layer, and is composed of an amorphous silicon semiconductor containing hydrogen, such as a-Si, a-SiC, and a-Si.
O, a-SiN, a-SiON, a-SiCON, etc. are mentioned. Among them, a-Si, which has a large light absorption coefficient, is most suitable. Hydrogen (H, D) and fluorine contained in the i-layer serve to compensate dangling bonds in the i-layer and improve the product of carrier mobility and lifetime in the i-layer. Further, it has a function of compensating for the interface state of the interface, and has an effect of improving the photovoltaic power, the photocurrent and the photoresponsiveness of the photovoltaic device. The i-layer has a hydrogen and fluorine content of 1 to 30
At% is mentioned as the optimum content. The content of carbon is preferably 10 ppm to 20%, the content of oxygen is 100 ppm to 10%, and the content of nitrogen is preferably 1 ppm to 10%.

The i-layer of the present invention has a small tail state on the valence band side, and the inclination of the tail state is 6
The density is 0 meV or less, and the density of dangling bonds by electron spin resonance (ESR) is 10 ¹⁷ / cm ³ or less. It is desirable to use the above-described MWPCVD method for forming the i layer, more preferably, the RF power is simultaneously introduced in the MWPCVD method, and more desirably, as described above.
RF power and DC power are simultaneously introduced in the WPCVD method.

Wide band gap a-SiC, a-S
iO, a-SiN, a- SiON, a source gas is diluted 2 to 100 fold with H _2, D _2, He or the like gas when forming the a-SiCON like, to introduce a relatively high MW power preferable. (RF-i Layer) In the photovoltaic device of the present invention, the i layer may be composed of a plurality of layers, and the RF-i layer and M
Lamination of W-i layers is one of the preferred forms. RF-i
The layer is formed between the MW-i layer and the doping layer and is an important layer that transports photoexcited carriers and prevents the valence electron control agent in the doping layer from diffusing into the MW-i layer. R
As the F-i layer, a slightly p-type or slightly n-type layer can be used and is made of an amorphous silicon semiconductor. Amorphous silicon semiconductors are a-Si, a-SiC, a-S
iO, a-SiN, a-SiCO, a-SiON, a-
SiNC, a-SiCON, etc. are mentioned. As the RF-i layer on the light incident side, a-Si, a-SiC, a-Si
The open circuit voltage of the photovoltaic element can be improved by using a semiconductor such as O or a-SiN. The short-circuit current of the photovoltaic element can be improved by using a semiconductor such as a-Si for the RF-i layer on the side opposite to the light incident side.

Hydrogen (H, D) and fluorine contained in the RF-i layer serve to compensate dangling bonds in the RF-i layer, and the product of the mobility and the lifetime of the carrier in the RF-i layer. Is to improve. It also has the effect of compensating for the interface state of the interface, and has the effect of improving the photovoltaic power, photocurrent, and photoresponsiveness of the photovoltaic device. The optimum content of hydrogen and fluorine-containing cloud in the RF-i layer is 1 to 30 at%. When carbon is contained, the content is 10 ppm to 2
0%, when oxygen is contained, the content is 100 ppm
10%, when nitrogen is contained, the content is 1 ppm to 1
0% is a suitable range.

The optimum layer thickness of the RF-i layer is 0.5 to 50 nm, and the tail state on the valence band side is small, and the slope of the tail state is 55 m.
eV or less, and the density of dangling bonds by electron spin resonance (ESR) is 10 ¹⁶ / cm ³ or less. (Transparent electrode) The transparent electrode is made of indium oxide (In
₂ O _3), tin oxide compound _{(SnO 2, ITO (In 2} O 3 -S
nO ₃ ) is a suitable material, and these materials may contain fluorine.

A sputtering method or a vacuum evaporation method is the most suitable deposition method for depositing the transparent electrode. When depositing by a sputtering method, a target such as a metal target or an oxide target is appropriately combined and used. When depositing by a sputtering method, the substrate temperature is an important factor, and 20 ° C. to 600 ° C. is mentioned as a preferable range. Further, as a gas for sputtering when depositing the transparent electrode by a sputtering method, an inert gas such as Ar gas can be used. Further, it is preferable to add oxygen gas (O ₂ ) to the inert gas as needed. Especially when a metal is used as a target, oxygen gas (O ₂ ) is essential. Further, when the target is sputtered with the inert gas or the like, the pressure of the discharge space is in order to perform the sputtering effectively,
A preferred range is 0.1 to 50 mTorr. The deposition rate of the transparent electrode depends on the pressure in the discharge space and the discharge power, and the optimum deposition rate is 0.01 to 10
The range is nm / sec.

Suitable evaporation sources for depositing transparent electrodes in the vacuum evaporation method include metallic tin, metallic indium, and
An indium-tin alloy is mentioned. Moreover, the range of 25 ° C. to 600 ° C. is a suitable range for the substrate temperature when depositing the transparent electrode. Further, it is preferable to introduce oxygen gas (O ₂ ) and deposit at a pressure of 5 × 10 ⁻⁵ Torr to 9 × 10 ⁻⁴ Torr. By introducing oxygen in this range, the metal vaporized from the vapor deposition source reacts with oxygen in the vapor phase to deposit a good transparent electrode. The preferable deposition rate range of the transparent electrode under the above conditions is 0.01 to 10 nm / sec. Deposition rate is 0.0
If it is less than 1 nm / sec, the productivity will decrease and 10 nm /
When it is larger than sec, a rough film is formed, which is not preferable in terms of transmittance, conductivity and adhesion.

The layer thickness of the transparent electrode is preferably deposited under conditions that satisfy the conditions of the antireflection film. As a specific layer thickness of the transparent electrode, 50 to 500 nm is mentioned as a preferable range. (Collector electrode) In order to allow more light to enter the i-layer, which is the photovoltaic layer, and to efficiently collect the generated carriers in the electrode, the shape of the collector electrode (the shape viewed from the incident direction of light), And the material is important. Usually, a comb-shaped collector electrode is used, and the line width, the number of wires, etc. are determined by the shape and size of the photovoltaic element viewed from the light incident direction, the material of the collector electrode, and the like. The line width is usually about 0.1 mm to 5 mm. The material of the collecting electrode is Fe, Cr, Ni, Au,
Ti, Pd, Ag, Al, Cu, AlSi, C (graphite) or the like is used, and usually Ag, which has a small specific resistance,
Metals such as Cu, Al, Cr and C, or alloys thereof are suitable. The layer structure of the collector electrode may be a single layer or may be a plurality of layers. These metals are vacuum deposited,
It is desirable to form it by a sputtering method, a plating method, a printing method, or the like. A suitable layer thickness is 10 nm to 0.5 mm.

When the vacuum evaporation method is used, a mask having a current collecting electrode shape is brought into close contact with the transparent electrode, and a desired metal deposition source is evaporated in a vacuum by electron beam or resistance heating.
A collecting electrode having a desired shape is formed on the transparent electrode. ´
In the case of forming by a sputtering method, a mask having a current collecting electrode shape is brought into close contact with the transparent electrode, Ar gas is introduced into a vacuum, DC is applied to a desired metal sputter target, and glow discharge is generated. Then, metal is sputtered to form a collector electrode having a desired shape on the transparent electrode.

When forming by a printing method, Ag paste, Al paste, or carbon paste is printed by a screen printing machine. The photovoltaic element having the pin structure has been described above, but the pinpin structure and the pinpin structure have been described.
Photovoltaic device in which a pin structure such as a pin structure is stacked, or a nip structure, a nipnip structure, or a nipnipn
The present invention can also be applied to a photovoltaic element having a laminated nip structure such as an ip structure.

[0073]

EXAMPLES The photovoltaic element of the present invention will be described in detail below by making a solar cell and a photosensor as an example of the photovoltaic element of the present invention, but the present invention is not limited thereto. << Example 1-1 >> A solar cell having the configuration shown in FIG. 1 was produced using the deposition apparatus shown in FIG.

First, a substrate was manufactured. 0.5m thickness
A stainless steel substrate of m × 50 × 50 mm ² was ultrasonically cleaned with acetone and isopropanol, and dried with warm air. DC
A light reflection layer of Ag having a layer thickness of 0.3 μm is formed on the surface of the stainless steel substrate at room temperature by the magnetron sputtering method, and the light reflection layer is formed on the surface of the stainless steel substrate by the RF magnetron sputtering method.
A transparent conductive layer of ZnO having a layer thickness of 1.0 μm is formed at 0 ° C.,
The fabrication of the substrate was completed.

The deposition apparatus 200 uses the MWPCVD method and RFP.
Both of the CVD methods can be carried out, and this was used to form a pin layer on the ZnO transparent conductive layer. The details will be described below. A source gas supply device (not shown) is connected to the deposition device through a gas introduction pipe.

The raw material gas cylinders were all refined to ultra-high purity. SiH ₄ gas cylinders, SiF ₄ gas cylinders, CH ₄ gas cylinders, GeH ₄ gas cylinders, GeF ₄ gas cylinders, PH ₃ / H ₂ (dilution: 100 ppm) gas cylinders , B ₂ H ₆ / H ₂ (dilution: 100 ppm) gas cylinder, H ₂ gas cylinder, NO / He (dilution: 1%) gas cylinder were connected. An RF power source was used as the bias power source.

Next, the back surface of the substrate 204 on which the reflective layer and the transparent conductive layer are formed is brought into close contact with the heater 205, the leak valve 209 in the deposition chamber 201 is closed, the conductance valve 207 is fully opened, and a vacuum (not shown) is provided. The inside of the deposition chamber 201 was evacuated by the exhaust pump until the pressure became about 1 × 10 ⁻⁵ Torr. After the preparation for film formation is completed as described above, an n layer (M
WPCVD method), aS containing microcrystalline germanium
i layer made of i (MWPCVD method (2)), a-SiC
P layers (RFPCVD method) are sequentially formed. The forming conditions are shown in Table 3 (a). When each layer is formed, H ₂ gas is introduced into the deposition chamber 201, and the pressure is adjusted by the conductance valve so that the pressure becomes the forming pressure of each layer. When the substrate temperature is stabilized at the desired temperature, the source gas is changed to the desired one. Only the flow rate was introduced into the deposition chamber.

Next, in the case of the RFPCVD method, the power of the RF power source is set to a desired value, and in the case of performing the MWPCVD method, it is set to M.
The power of the W power source is set to a desired value, a bias is applied as necessary, plasma is generated, the shutter is opened, and when the desired layer thickness is formed, the shutter is closed, the RF power source and the MW power source are turned off, Extinguished the plasma. In addition,
When forming the i layer, GeH ₄ gas was introduced from the gas introduction pipe 221 to generate plasma in the region (A) and plasma of SiH ₄ and H _{2 in} the region (B). Stop the flow of the raw material gas into the deposition chamber and put H ₂ into the deposition chamber for 5 minutes.
After continuing to flow the gas, stopping the inflow of H ₂ and evacuating the deposition chamber and the gas pipe to 1 × 10 ⁻⁵ Torr,
The next layer was formed.

Next, a layer having a thickness of 70 n is formed as a transparent electrode on the p layer.
m of ITO was formed by vacuum deposition. Next, a mask with comb-shaped holes was placed on the transparent electrode, and Cr (40 nm) /
A comb-shaped collector electrode made of Ag (1000 nm) / Cr (40 nm) was formed by a vacuum evaporation method.

Thus, the production of the solar cell (SC Ex 1-1) was completed. << Example 1-2 >> In this example, when the i layer is formed, GeH ₄ gas is introduced from the gas introduction pipe 221 to generate plasma in the region (A) and SiH _{4 in the} region (B). And H ₂ plasma were generated, and the SiH ₄ gas flow rate and the GeH ₄ gas flow rate were temporally changed.

Others were the same as in Example 1-1. The production conditions are shown in Table 3 (b).

[0082]

[Table 3] This completes the production of the solar cell (SC Ex 1-2).

<Comparative Example 1-1-1> When forming the i layer,
GeH ₄ gas was not introduced, and SiH ₄ gas flow rate was 150 sc
A solar cell (SC ratio 1-1-1) was produced under the same conditions as in Example 1-1 except that the height was changed to cm. <Comparative Example 1-1-2> When the i layer was formed, GeH ₄ gas was not introduced, and the flow rate of SiH ₄ gas was changed to 150 sccm.
-1-2) was produced.

<Comparative Example 1-2-1> When forming the i layer,
Plasma is not generated in the area (A), and S is generated in the area (B).
A solar cell (SC ratio 1-2) was prepared under the same conditions as in Example 1-1, except that iH ₄ , GeH ₄ , and H ₂ gas plasmas were generated.
-1) was produced. <Comparative Example 1-2-2> When the i layer is formed, plasma is not generated in the region (A), and SiH ₄ , Ge is generated in the region (B).
Example 1-Except that plasma of H ₄ and H ₂ gas is generated
A solar cell (SC ratio 1-2-2) was produced under the same conditions as in 2.

(Evaluation 1) The initial photoelectric conversion efficiency (photovoltaic power / incident optical power) was calculated by using the solar cells (SC Ex 1-1), (SC ratio 1-1-1), and (SC ratio 1-2-1). ) Was measured. For the measurement of the initial photoelectric conversion efficiency,
It was obtained by arranging under AM · 1.5 (100 mW / m ² ) light irradiation and measuring VI characteristics. As a result of the measurement, (SC ratio 1-1) to (SC ratio 1-1-
1), the initial photoelectric conversion efficiency of (SC ratio 1-2-1) is 0.
It was 94 times and 0.95 times.

(Evaluation 2) The initial photoelectric conversion efficiency (photovoltaic power / incident optical power) was calculated by using the solar cells (SC Ex 1-2), (SC ratio 1-1-2), and (SC ratio 1-2-2). Was measured. For the measurement of the initial photoelectric conversion efficiency,
It was obtained by arranging under AM · 1.5 (100 mW / m ² ) light irradiation and measuring VI characteristics. As a result of the measurement, (SC ratio 1-2) to (SC ratio 1-1-
2), the initial photoelectric conversion efficiency of (SC ratio 1-2-2) is 0.
It was 92 times and 0.93 times.

Next, the i layer of (SC Ex 1-2) was analyzed. The samples in the table below were prepared on a glass substrate.

[0088]

[Table 4] The conditions other than the gas flow rate were the same as in Example 1-2. When Raman scattering was measured using the samples of (SP-1) to (SP-5), a sharp peak corresponding to microcrystalline germanium having a Raman shift of 300 cm ^{−1 and} a non-peak of 480 cm ⁻¹ were obtained for each sample. A broad peak corresponding to crystalline silicon was observed.

When the crystallinity was evaluated by electron diffraction, a sharp ring was observed in the broad ring in each sample. Further, in the high resolution electron microscope observation, a minute crystal region corresponding to the microcrystalline germanium is observed, and as the GeH ₄ flow rate increases, the grain size becomes 60 to 470.
It was found that the number of microscopic regions of Å increased and the content of microcrystalline germanium increased. Therefore (SC Ex 1-2)
8 (a) shows the microcrystalline germanium content in the i-layer of FIG.
It turned out that it changed like. Further, when the bandgap of each sample was measured using a spectrophotometer, it was found that the change in the bandgap of (SC Ex 1-2) in the layer thickness direction was as shown in FIG. 9A.

In addition, (Comparative Example 1-1-2) and (Comparative Example 1)
A similar sample corresponding to -2-2) was prepared and the same analysis was performed. As a result, in the sample of (Comparative Example 1-1-2), no result indicating the presence of microcrystalline germanium was obtained. In the sample of (Comparative Example 1-2-2), a fine crystal region having a grain size of 10 to 20Å corresponding to microcrystalline germanium was observed by observation with a high resolution electron microscope.

As described above, the solar cell of the present invention (SC Ex 1
-1), (SC Ex 1-1) is a solar cell (SC ratio 1-1
-1), (SC ratio 1-2-1), (SC ratio 1-1-
2), (SC ratio 1-2-2) was found to have more excellent characteristics. << Example 2-1 >> A solar cell (SC Ex 2-1) was produced using the forming method of (1). The formation of the i layer was performed under the same conditions as in Example 1-1, except that the pressure in the plasma region (B) was 70 mTorr. When the same measurement as in Example 1-1 was performed, the solar cell of (SC Ex 2-1) was the same as in Example 1-1, and the solar cell of Comparative Example (SC ratio 1-1
-1), (SC ratio 1-2-1) was found to have a further excellent characteristic. When the i layer was analyzed in the same manner as in Example 1, the result showing the presence of microcrystalline germanium having a grain size of 60 to 420Å was obtained.

Example 2-2 A solar cell (SC Ex 2-2) was produced using the forming method of (1). When forming the i layer, the same conditions as in Example 1-2 were performed except that the pressure in the plasma region (B) was set to 80 mTorr. Example 1
-2, the solar cell of (SC Ex 2-2) was compared with the solar cell of Comparative Example (S
It was found that the characteristics were more excellent than the C ratio 1-1-2) and the (SC ratio 1-2-2).

When the i layer was analyzed in the same manner as in Example 1-2, the results showed that microcrystalline germanium having a grain size of 70 to 420Å was contained and the content thereof varied in the layer thickness direction. Was given. Example 3-1 A photodiode for an infrared photosensor having the layer structure shown in FIG. 1 was produced. 0.5m thickness
m, 50 × 50 mm ² glass substrate was ultrasonically washed with acetone and isopropanol, dried with warm air, and a 0.1 μm thick Al light reflection layer was formed on the glass substrate surface at room temperature by vacuum deposition. The fabrication of the substrate was completed.

A p-layer (a-Si layer thickness of 50 nm) and an i-layer (a-Si: mc-) were formed on the substrate in the same manner as in Example 1-1.
Ge substrate temperature 390 ° C., layer thickness 600 nm, n layer (a
-SiC layer thickness 20 nm) was sequentially formed. Next, a transparent electrode and a collector electrode similar to those in Example 1-1 were formed on the n-layer to manufacture a photodiode (PD Ex 3-1). Example 3-2 A photodiode for an infrared photosensor having the layer structure shown in FIG. 1 was produced. 0.5m thickness
m, 50 × 50 mm ² glass substrate was ultrasonically cleaned with acetone and isopropanol, dried with warm air, and a light-reflecting layer of Al having a thickness of 0.1 μm was formed on the surface of the green glass substrate by vacuum deposition at room temperature. After that, the substrate was manufactured. In the same manner as in Example 1, the content of microcrystalline germanium in the i layer was changed in the layer thickness direction, and the p layer (a-Si layer thickness 50 n was formed on the substrate.
m), i layer (a-Si: mc-Ge) substrate temperature 390 ° C.
A layer thickness of 500 nm) and an n layer (a-SiC layer thickness of 10 nm) were sequentially formed. Next, a transparent electrode and a collector electrode similar to those in Example 1-2 were formed on the n-layer to manufacture a photodiode (PD Ex 3-2).

<Comparative Example 3-1-1> When forming the i layer,
GeH ₄ gas was not introduced, and SiH ₄ gas flow rate was 150 sc
A photodiode (PD ratio 1-1-1) was produced under the same conditions as in Example 3-1 except that the thickness was changed to cm. <Comparative Example 3-1-2> When forming the i-layer, GeH ₄ gas was not introduced, and the flow rate of SiH ₄ gas was set to 150 sccm.
Ratio 1-1-2) was produced.

<Comparative Example 3-2-1> When forming the i layer,
Plasma is not generated in the area (A), and S is generated in the area (B).
A photodiode (PD) is manufactured under the same conditions as in Example 3-1 except that plasma of iH ₄ , GeH ₄ , and H ₂ gas is generated.
The ratio 3-2-1) was produced. <Comparative Example 3-2-2> When the i layer is formed, plasma is not generated in the region (A), and SiH ₄ , Ge is generated in the region (B).
Example 3 except that plasma of H ₄ and H ₂ gas is generated
Photodiode under the same conditions as 2 (PD ratio 3-2-2)
Was produced.

(Evaluation: PD Ex 3-1) The afterimage characteristics of the manufactured photodiode were measured. Afterimage characteristics are GaAlA
The photocurrent / dark current (measurement frequency 10 kHz) when s-LED (center wavelength 880 nm) was irradiated with infrared light was measured. The temperature characteristics were also measured.

As a result, the photodiode (P
D Ex 3-1) is a photodiode (PD ratio 3-
It has been found that the characteristics are more excellent than those of 1-1) and (PD ratio-12-1). When an i-layer sample similar to that of Example 1-1 was prepared and analyzed, (PD Ex.
It was found that -1) contained microcrystalline germanium having a particle size of 70 to 480Å.

(Evaluation: PD Ex 3-2) The afterimage characteristics of the manufactured photodiode were measured. Afterimage characteristics are GaAlA
The photocurrent / dark current (measurement frequency 10 kHz) when s-LED (center wavelength 880 nm) was irradiated with infrared light was measured. The temperature characteristics were also measured.

The same measurement was performed in a vibration environment with a frequency of 60 Hz and an amplitude of 0.2 mm. As a result, the photodiode of the present invention (PD Ex 3-2) was compared with the photodiode of the comparative example (PD ratio 3-1-2), (PD ratio 3-12).
It was found that it has more excellent characteristics than that of -2). When an i-layer sample similar to that in Example 1-1 was prepared and analyzed, (PD Ex 3-1) had a particle size of 70 to 48.
It contains 0Å microcrystalline germanium and its content is as shown in FIG.
It was found that the distribution shown in FIG.

Example 4-1 A solar cell formed by using Si ₂ H ₆ gas instead of SiH ₄ gas (SC Ex 4-
1) was produced. A solar cell was prepared in the same manner as in Example 1-1, except that Si ₂ H ₆ gas was introduced at 70 sccm instead of SiH ₄ gas in Example 1-1.
When the same measurement as in -1 was performed, it was found that the solar cell had better characteristics than the solar cells (SC ratio 1-1-1) and (SC ratio 1-2-1) of the comparative examples.

Example 4 Instead of SiH ₄ gas, Si ₂
A solar cell (SC Ex 4-2) formed using H ₆ gas was produced. In Example 1, S was used instead of SiH ₄ gas.
A solar cell was prepared in the same manner as in Example 1 except that the i ₂ H ₆ gas was introduced with a time change of 70 → 55 → 70 sccm, and the same measurement as in Example 1-2 was performed. Solar cells (SC ratio 1-1-2), (SC ratio 1-2
It was found to have better properties than 2).

<< Example 5-1 >> Using the method of (I), i containing both microcrystalline silicon and microcrystalline germanium
A solar cell having layers (SC Ex 5-1) was produced. When forming the i layer in Example 1-1, SiF ₄ gas (3
0 sccm) newly introduced. Otherwise, Example 1-1
It was made under the same conditions as. When the same measurement as that of Example 1-1 was performed, the solar cell (SC Ex 5-1) was (SC Ex 1-
It has been found that it has a further excellent characteristic than 1).

When the i layer was analyzed by Raman scattering in the same manner as in Example 1-1, a sharp peak at 520 cm ⁻¹ corresponding to microcrystalline silicon and a sharp peak at 300 cm ⁻¹ corresponding to microcrystalline germanium were obtained. Raman shift was observed. Example 5-2 Using the method of (I), a solar cell (SC Ex 5-2) having an i layer containing both microcrystalline silicon and microcrystalline germanium was produced. When forming the i-layer in Example 1-2, SiF ₄ gas (30 scc
m) Newly introduced. Other than that, it produced on the same conditions as Example 1-2. When the same measurement as in Example 1-2 was performed, it was found that the solar cell (SC Ex 5-2) had further excellent characteristics as compared to (SC Ex 1-2).

When the i layer was analyzed by Raman scattering in the same manner as in Example 1-2, a sharp peak at 520 cm ^-1 corresponding to microcrystalline silicon and a sharp peak at 300 cm ^-1 corresponding to microcrystalline germanium were obtained. Raman shift was observed. Example 6-1 Using the method of (I), a solar cell having an n layer containing both microcrystalline silicon and microcrystalline germanium was produced.

In forming the n-layer in Example 1-1,
GeF ₄ gas was newly introduced and the flow rate was changed with time.
Other conditions were the same as in Example 1-1. When the same measurement as in Example 1-1 was performed, a solar cell (S
It was found that C Ex 6-1) had better characteristics than (SC Ex 5-1). When the n layer was analyzed by Raman scattering in the same manner as in Example 1-1, a Raman shift of a sharp peak at 520 cm ⁻¹ corresponding to microcrystalline silicon and a sharp peak at 300 cm ⁻¹ corresponding to microcrystalline germanium was observed. Was done.

Example 6-2 Using the method of (I), a solar cell was produced in which both microcrystalline silicon and microcrystalline germanium were contained, and the microcrystalline silicon content varied in the layer thickness direction. When forming the i layer in Example 1-2,
SiF ₄ gas was newly introduced and the flow rate was changed with time.
The other conditions were the same as those in Example 1-2.

When the same measurement as in Example 1-2 was carried out, it was found that the solar cell (SC Ex 6-2) had better characteristics than (SC Ex 5-2). Example 1
When the i layer was analyzed by Raman scattering in the same manner as in -2, a sharp Raman shift of 520 cm ^-1 corresponding to microcrystalline silicon and a sharp peak of 300 cm ^-1 corresponding to microcrystalline germanium were observed.

A sample was prepared in the same manner as in Example 1-2, and a microscopic region corresponding to microcrystalline silicon was observed.
The content of microcrystalline silicon in the layer thickness direction is shown in FIG.
It turned out that it became like. Example 7-1 Using the deposition apparatus using the roll-to-roll method of FIG. 6, the pinpin solar cell (SC Ex 7) of FIG. 4 was produced. This equipment is a substrate delivery chamber 5
10, a plurality of deposition chambers 301 to 309, and a substrate winding chamber 311 are sequentially arranged, and they are connected by a separation passage 312, and a belt-shaped substrate 313 passes through them, and a substrate delivery chamber From the substrate to the substrate winding chamber, and each deposited film can be simultaneously formed in each deposition chamber.

DC magnetron sputtering can be performed in the deposition chamber 301, and RF magnetron sputtering can be performed in the deposition chambers 302 and 309.
The MWPCVD method can be performed by attaching a microwave applicator in 304, 307, and 308, and RF can be internally provided in the deposition chambers 305 and 306.
The RFPCVD method can be performed by arranging the electrodes. A halogen lamp heater 318 for heating the substrate is installed in each deposition chamber.

350 (a) (FIG. 7 (a)) shows the deposition chamber 3
03-308 as viewed from above, each deposition chamber has a gas inlet 314 and an exhaust outlet 315. In each deposition chamber, the gas exhaust direction is toward the back side of the paper. Deposition chamber 301,
302 and 309 each have an Ar gas inlet 326, and each of the deposition chambers 303 to 308 has a raw material gas inlet 314 for forming a deposited film by the plasma CVD method. The supply device is connected.

A vacuum chamber 332 for generating a plasma region (A) is further connected to the deposition chamber 304, and a radical containing germanium is generated in the vacuum chamber 332 and supplied to the deposition chamber 304. ing.
A mechanical booster pump as a vacuum exhaust pump is connected to the exhaust ports of the deposition chambers 305 and 306, and an oil diffusion pump is connected to the other deposition chambers, the substrate delivery chamber, and the substrate winding chamber. An RF power source is connected to the RF electrode, and a MW power source is connected to the microwave applicator. Further, a bias electrode 331 is installed in the deposition chambers 304 and 307, which are the deposition chambers for the i layer, and R
F power supply is connected.

Further, Ag is used as a target in the deposition chamber 301,
ZnO was used as the target of the deposition chamber 302, and In ₂ O ₃ —SnO ₂ (5%) was used as the target of the deposition chamber 309.
The separation passage connected to each deposition chamber has an inlet 319 through which a scavenging gas flows, and a scavenging gas as shown in FIG. The substrate delivery chamber has a delivery roll 320 and a guide roller 321 for applying an appropriate tension to the substrate and keeping the substrate always horizontal. The substrate delivery chamber has a winding roll 322 and a guide roller 323.

First, a long stainless sheet having a length of 300 m, a width of 50 cm and a thickness of 0.1 mm is wound around a delivery roll, set in a substrate delivery chamber, passed through each deposition chamber, and then the end of the substrate is wound onto the substrate. Wrap around the take-up roll. The entire apparatus is evacuated by a vacuum exhaust pump, the lamp heater in each deposition chamber is turned on, and the substrate temperature in each deposition chamber is set to each predetermined temperature. Inlet 519 for scavenging gas when the pressure of the entire device falls below 1 mTorr
Each scavenging gas was introduced from the above, and while the substrate was moved in the direction of the arrow in the drawing, it was wound by a winding roll, and a predetermined amount of Ar gas was flown into the deposition chambers 301, 302, 309. In each of the other deposition chambers, the respective source gas is made to flow.
At this time, the flow rate of the scavenging gas flowing into each separation passage and the pressure in each deposition chamber were adjusted so that the raw material gas flowing into each deposition chamber did not diffuse to the other deposition chambers. Next, DC power, RF power, and MW power are introduced into each deposition chamber to generate plasma,
Sputtering is performed in the deposition chambers 301, 302, 309, RFPCVD is performed in the deposition chambers 305, 306, MWPCVD is performed in the other deposition chambers, and each deposited film is continuously formed simultaneously in each deposition chamber. It was.

A light reflection layer (Ag
A substrate temperature of 350 ° C. and a film thickness of 0.3 μm are formed, and a transparent conductive layer (ZnO substrate temperature of 350 ° C.) is formed in the deposition chamber 302.
Film thickness 2.0 μm), n1 layer (P-doped a-Si layer thickness 20 nm) in the deposition chamber 303, first i1 in the deposition chamber 304
Type layer (a-Si: mc-Ge layer thickness 180 nm), the first p1 type layer (B-doped a-Si layer thickness 1) in the deposition chamber 305.
0 nm), the second n2-type layer (P-doped a
-Si layer thickness of 20 nm), i2 type skin (a
-Si layer thickness 250 nm), second p2 in deposition chamber 308
Mold layer (B-doped a-SiC layer thickness 5 nm), deposition chamber 30
9 transparent electrode (ITO substrate temperature 160 ℃ layer thickness 70n
m) were formed in sequence.

When the substrate is completely wound, the plasma is extinguished, the introduction of all gases is stopped, and the vacuum is exhausted until the pressure inside the deposition chamber becomes 0.1 mTorr or less. Then, the entire deposition apparatus is leaked and rolled. The substrate was taken out. When the surface roughness of the substrate was examined with a stylus type film thickness meter, it was found that the height of peaks was 0.21 μm on average. This is because the substrate temperature when forming the Ag light-reflecting layer and the ZnO transparent conductive layer was as high as 350 ° C., and the surface of these films was textured.

Next, a two-layered collecting electrode was formed by a screen printer using a roll-to-roll system. First, a comb-shaped carbon paste having a thickness of about 3 μm is printed on the surface of the transparent electrode of ITO and dried, and then an Ag paste having the same shape and a thickness of about 10 μm is printed on the surface of the carbon paste and dried. It was cut into a size of 10 cm × 25 cm.

Example 7-2 In this example as well, the roll of FIG.
Using a deposition apparatus using the two-roll method, p in FIG.
An inpin type solar cell (SC Ex 7-2) was produced. However, 350 (b) shown in FIG. 7 (b) is a view of the deposition chamber 304 seen from above, but in this example, there are a plurality of introducing pipes, and the radical R containing germanium introduced into each introducing pipe is introduced.
By changing the flow rate of g for each gas introduction tube, it is possible to spatially change the germanium-containing radicals incident on the substrate surface, and to change the content of microcrystalline germanium in the formed i-layer. It can be changed in the thickness direction. In addition, in 350b, the amount of radicals introduced is shown by the size of the arrow.

In this example, a light reflection layer (Ag substrate temperature 350 ° C., film thickness 0.3 μm) is formed on the substrate in the deposition chamber 301, and a transparent conductive layer (ZnO substrate temperature 350 ° C. film thickness 2 is formed in the deposition chamber 302. 0.0 μm), an n1 layer (P-doped a-Si layer thickness 30 nm) in the deposition chamber 303, and a first i1-type layer (a-Si: mc-Ge layer thickness 120 n in the deposition chamber 304).
m), the first p1-type layer (B-doped a-S) in the deposition chamber 305.
i layer thickness 20 nm), second n2 type layer (P-doped a-Si layer thickness 20 nm) in the deposition chamber 306, i2 type skin (a-Si layer thickness 220 nm) in the deposition chamber 307, deposition chamber 308
And the second p2-type layer (B-doped a-SiC layer thickness 5n
m), a transparent electrode (ITO substrate temperature 16
0 ° C. layer thickness 70 nm) was sequentially formed. When forming the i1 layer, the GeH ′ flow rate was changed with time to change the content of the microcrystalline germanium as shown in FIG. 8C.

After the substrate has been wound, the plasma is extinguished, the introduction of all gases is stopped, and the chamber is evacuated until the pressure inside the deposition chamber becomes 0.1 mTorr or less. Then, the entire deposition apparatus is leaked and rolled. The substrate was taken out. When the surface roughness of the substrate was examined with a stylus type film thickness meter, it was found that the height of peaks was 0.23 μm on average. This is because the substrate temperature when forming the Ag light-reflecting layer and the ZnO transparent conductive layer was as high as 350 ° C., and the surface of these films was textured.

Next, a two-layered collecting electrode was formed by a screen printer using a roll-to-roll system. First, a comb-shaped carbon paste having a thickness of about 3 μm is printed on the surface of the transparent electrode of ITO and dried, and then an Ag paste having the same shape and a thickness of about 10 μm is printed on the surface of the carbon paste and dried. It was cut into a size of 10 cm × 25 cm.

<Comparative Example 7-1> When forming the i1 layer, plasma is not generated in the region (A), and Si is generated in the region (B).
Except for generating plasma of H ₄ , GeH ₄ , and H ₂ gas,
A pinpin type solar cell (SC ratio 7-1) was produced under the same conditions as in Example 7-1. When the same measurement as that of Example-11 was performed (SC Ex 7-1), (SC ratio 7
It was found that it has better characteristics than -1).

<Comparative Example 7-2> When the i1 layer is formed, plasma is not generated in the region (A) and Si is generated in the region (B).
Except for generating plasma of H ₄ , GeH ₄ , and H ₂ gas,
A pinpin type solar cell (SC ratio 7-2) was produced under the same conditions as in Example 7-2. When the same measurement as that in Example 1-2 was performed (SC Ex 7-2), the SC ratio 7
It has been found that it has better characteristics than that of -2).

Example 8-1 The pinpin type solar cell produced in Example 7-1 was modularized and subjected to a field test. Light-irradiated 10 produced in Example 7
Sixty-five cm × 25 cm solar cells (SC Ex 7) were prepared. An adhesive sheet made of EVA (ethylene pinyl acetate) is placed on a 5.0 mm thick aluminum plate, a nylon sheet is placed on it, and 65 intestinal cells are arranged on it to suit the load. Thus, serialization and parallelization were performed. An EVA adhesive sheet was placed on top of this, a fluororesin sheet was placed on top of it, and vacuum laminated to produce a module (MJ Ex 8-2).

Example 8-2 The pinpin type solar cell prepared in Example 7-2 was modularized and subjected to a field test. Light-irradiated 10 produced in Example 7
65 solar cells (SC Ex 7-2) having a size of 25 cm × 25 cm were prepared. EVA on a 5.0 mm thick aluminum plate
An adhesive sheet made of (ethylene pinyl acetate) was placed, a nylon sheet was placed on the sheet, and 65 gut cells were arranged on the sheet, and serialization and parallelization were performed so as to match the load. An EVA adhesive sheet was placed on top of this, a fluororesin sheet was placed on top of it, and vacuum laminated to produce a module (MJ Ex 8-2).

<Comparative Example 8-1> A solar cell not irradiated with light (S
A module (MJ ratio 8-1) was produced in the same manner as in Example 8-1 by using 65 C ratios 7-1). The two modules were installed at the angle that could collect the most sunlight. The measurement of the field test was performed by measuring the photoelectric conversion efficiency after one year and determining the deterioration rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency).

As a result, the module (MJ Ex. 8-1) using the solar cell of the present invention is the same as the conventional module (MJ ratio 8).
It was found that the initial photoelectric conversion efficiency and field durability were even better than those of -1). <Comparative Example 8-2> Solar cell not irradiated with light (SC ratio 7-2)
The module (MJ
The ratio 8-2) was produced.

The two modules were installed at an angle where the sunlight could be collected most. The measurement of the field test was performed by measuring the photoelectric conversion efficiency after one year and determining the deterioration rate (photoelectric conversion efficiency after one year / initial photoelectric conversion efficiency). As a result, the module (MJ Ex 8-2) using the solar cell of the present invention is a conventional module (MJ ratio 8-2).
It was found that it has an even better initial photoelectric conversion efficiency and field durability.

As described above, it was found that the effect of the photovoltaic element of the present invention can be exerted regardless of the element, the element structure and the element material.

[0130]

In the photovoltaic device of the present invention, the sensitivity at long wavelength and the fill factor can be improved, and the photoelectric conversion efficiency can be improved. Furthermore, photodegradation can be suppressed. It also has high field durability. And excellent temperature characteristics. In addition, the photo sensor can suppress afterimage and vibration deterioration.
Further, the photovoltaic device of the present invention is a microwave plasma CVD.
Since it is formed using the method, it has high productivity.

[Brief description of drawings]

FIG. 1 is a layer configuration diagram of a photovoltaic element of the present invention.

FIG. 2 is a layer configuration diagram of a photovoltaic element of the present invention.

FIG. 3 is a layer configuration diagram of a photovoltaic element of the present invention.

FIG. 4 is a layer configuration diagram of a photovoltaic element of the present invention.

FIG. 5 is a schematic view of a deposition apparatus used for manufacturing the photovoltaic element of the present invention.

FIG. 6 shows a roll used for manufacturing the photovoltaic element of the present invention.
It is the schematic of the deposition apparatus of a two roll method.

7 is a plan view of the deposition chamber shown in FIG.

FIG. 8 is a characteristic diagram showing changes in the content of microcrystalline germanium in the layer thickness direction in the present invention.

FIG. 9 is a characteristic diagram showing changes in the band gap in the layer thickness direction in the present invention.

FIG. 10 is a characteristic diagram showing changes in the microcrystalline silicon content in the layer thickness direction in the present invention.

[Explanation of symbols]

 101 substrate 102 n layer 103 i layer 104 p layer 105 transparent electrode 106 current collecting electrode 111 substrate 112 n1 layer 113 i1 layer 114 p1 layer 115 n2 layer 116 i2 layer 117 p2 layer 118 transparent electrode 119 current collecting electrode 121 substrate 122 n1 layer 123 i1 layer 124 p1 layer 125 n2 layer 126 i2 layer 127 p2 layer 128 n2 layer 129 i2 layer 130 p2 layer 131 transparent electrode 132 current collecting electrode 142 support 143 light reflection layer 144 transparent conductive layer 145 n1 layer 146 i1 layer 147 Layer 148 n2 layer 149 i2 layer 150 p2 layer 151 Transparent electrode 152 Current collecting electrode

Claims (9)

[Claims] 1. A photovoltaic element comprising a p-layer, an i-layer, and an n-layer formed of an amorphous silicon semiconductor containing hydrogen on a substrate, the i-layer being formed by a microwave plasma CVD method. , I layer is a region (A) of plasma generated by irradiating a gas containing germanium with microwaves.
And a region (B) of plasma generated by irradiating a gas containing silicon with microwaves is separated, and a radical Rg containing germanium generated in the region (A) and a region (B) generated The radical Rs containing silicon is formed by a method of reacting in a region (C) different from the region (A), and the i layer contains microcrystalline germanium, and the grain size of the microcrystalline germanium is 50 to 500Å. Photovoltaic device characterized by the above. 2. The photovoltaic element according to claim 1, wherein the region (C) is a surface of a p-layer, an i-layer or an n-layer. 3. The p-layer and / or the n-layer is formed by irradiating a plasma containing plasma (AA) generated by irradiating a germanium-containing gas with a microwave and irradiating a silicon-containing gas with a microwave. Area of plasma generated (B
B) is separated, and the germanium-containing radical R _ge generated in the region (AA) and the silicon-containing radical R _si generated in the region (BB) are separated in the region (CC) different from the region (AA). It is formed by a reaction method and contains microcrystalline germanium, and the grain size of the microcrystalline germanium is 5
The photovoltaic device according to any one of claims 1 to 3, wherein the photovoltaic device has a thickness of 0 to 500 Å. 4. The photovoltaic element according to claim 3, wherein the region (CC) is the surface of the substrate or the i layer. 5. The photovoltaic layer according to claim 1, wherein the i layer contains microcrystalline silicon, and the grain size of the microcrystalline silicon is 50 to 500Å. element. 6. The p-layer and / or the n-layer contains microcrystalline silicon, and the grain size of the microcrystalline silicon is 50 to 500Å.
The photovoltaic element according to any one of claims 1 to 5, wherein 7. The photovoltaic element according to claim 1, wherein the germanium content in the i layer changes in the layer thickness direction. 8. The photovoltaic element according to claim 7, wherein the position where the content of the microcrystalline germanium is maximum is between the central position of the i layer and the p layer. 9. The microcrystalline silicon content in the i-layer changes in the layer thickness direction, and the position where the content is the minimum is between the central position of the i-layer and the p-layer. The photovoltaic element according to claim 7 or 8.