JPH06181328A - Photovoltaic element and generating system - Google Patents

Abstract

PURPOSE:To restrain a photovolaic element from deteriorating in characteristics due to light and vibrations by applying a forward bias to the element by a method wherein an RF doped layer and an MW doped layer are arranged interposing an i-type bayer between them, and the i-type layer is made to change smoothly in alkaline metal and hydrogen content in its thicknesswise direction. CONSTITUTION:A photovoltaic element is formed through such a manner that an MW n-conductivity type layer 102 is formed on a substrate 101 through an MWPCVD method, an RF n-conductivity type layer 103 is formed thereon by a PFPCVD method, furthermore and RF p-type layer 105 formed by an RFPCVD method and an MW p-type layer 106 formed by an MWPCVD method are formed interposing between the layers 105, 106 an alkaline metal-containing i-type 104 formed by an MWPCVD method, and a transparent electrode 107 and a collecting electrode 108 are formed on the MWP-type layer 106. By this setup, a photovoltaic element of this constitution can be restrained from deteriorating in characteristics due to light and vibrations even if it stands in an environment of high temperature and high humidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pin type photovoltaic element and a power generation system made of a non-single crystal silicon semiconductor material. In particular, a photovoltaic element in which a doping layer and an i-type layer are formed by a microwave plasma CVD method (MWPCVD method) and a semiconductor layer made of a non-single-crystal silicon semiconductor material (simply referred to as a semiconductor layer) contains an alkali metal It is about. The present invention also relates to a photovoltaic element having excellent productivity. In addition, it relates to a power generation system using the photovoltaic element.

[0002]

2. Description of the Related Art In recent years, photovoltaic devices have been intensively studied by using the MWPCVD method, which has a higher deposition rate and is excellent in raw material gas utilization efficiency. For example, as an example in which the i-type layer is formed by the MWPCVD method, "a-Si solar cell by microwave plasma CVD method", Towa K.,
Takeshi Watanabe, Toshikazu Shimada, Proceedings of the 50th JSAP Academic Conference pp. 566. Etc. In this photovoltaic element, the i-type layer is formed by the MWPCVD method to obtain a high-quality i-type layer with a high deposition rate.

An example of forming the doping layer by the MWPCVD method is, for example, "High Efficien".
cy Amorphous Solar Cell E
mploying ECR-CVD Produced
p-Type Microcrystal S
iC Film ”, Y. Hattori, D. Krua
ngam, T .; Toyama, H .; Okamoto a
nd Y. Hamakawa, Proceedings
of the International PVS
EC-3 Tokyo Japan 1987 pp.
171. "HIGH-CONDUCTIVE WIDE
BAND GAP P-TYPE a-SiC: H
PREPARED BY ECR CVD AND I
TS APPLICATION TO HIGH EF
FICIENCY a-Si BASIS SOLAR
CELLS ", Y. Hattori, D. Kruan
gam, K .; Katou, Y. Nitta, H .; Oka
motor and Y. Hamakawa, Procee
ings of 19th IEE Photoshop
Itaic Specialists Confere
nce1987 pp. 689. Etc. In these photovoltaic elements, a good quality p-type layer is obtained by using the MWPCVD method for the p-type layer.

However, in these examples, the i-type layer and p
No MWPCVD method has been used to form both mold layers. Currently, i-type layer formed by MWPCVD method and MWP
It is considered that when a doping layer formed by the CVD method is stacked, many defect levels occur at the interface, and a photovoltaic element having good characteristics cannot be obtained.

Further, studies are underway on a non-single crystal silicon semiconductor material containing an alkali metal and a photovoltaic element using the same. For example, "Evolved l
itium-doped amourhousessi
licon solar cells. Final r
eport part 1 ", US DOE Rep,
No. DOE-ER-10504-1-PT-1 P
P. 13 1982, it is stated that lithium is an effective donor dopant.

In JP-A-57-90931, the dangling bonds are reduced by sputtering fluorides of lithium, sodium, cesium and rubidium simultaneously with silicon to obtain a thermally stable doping layer. Not used for layers. Further, in this example, the alkali metal is the main constituent element.

In Japanese Patent Laid-Open No. 03-136284, the i-type layer is heavily doped with lithium to improve the photoelectric conversion efficiency of the photovoltaic element. However, also in this example, lithium is the main constituent element of the i-type layer, and it is contained non-uniformly, and further, the relation between the non-uniformity and the hydrogen content, the relation with the fluorine content, the light deterioration, and the vibration deterioration. The relationship is not mentioned.

JP-A-61-255073 describes that the photoelectric conversion efficiency of a photovoltaic element can be improved by the presence of a region in which the minimum sodium content of the i-type layer is 5 × 10 ¹⁸ cm ^-3 or less. . However, in this example, the sodium content is high near the interface.

Further, investigations on a non-single crystal silicon semiconductor layer containing fluorine and a photovoltaic element using the same are also underway. For example, "Practical research on amorphous solar cells, research on amorphous solar cell high-reliability element manufacturing technology,"
Overview of research and development of Sunshine Project. Solar energy −
1. Light Utilization Technology VOL. 1985 pp. I. 231
-I. 243 1986. "The chemical
and configurational bassi
s of high efficiency amor
phos photovoltaic cell
s ", Ovshinsky. SR, Proceedi.
ngs of 17th IEEE Photovol
taic Specialists Conferen
ce 1985 pp. 1365. "Preparat
ion and properties of spu
tered a-Si: H: F films ”, Be
yer. W. Chevallier. J, Reiche
lt. K, Solar Energy Material
l vol. 9, No 2, pp. 229-245 19
83. Development of the sci
entific and technical bas
is for integrated amorpho
us silicon modules. Resea
rch on a-Si: F: H (B) alloys
and module testing at IET
-CIEMAT. ", Gutierrez M T, P
Delgado L, Photovolt, Powe
r Gener. , Pp. 70-751988. "Th
e effect of fluorine on t
he photovoltaic property
s of amorphos silicon ”, Ko
Nagai M, Nishihata K, Takah
ashiK, Komoro K, Proceeding
s of 15th IEE PHOTOVOLTAI
c Specialists Conference1
981 pp. 906. Etc. However, although the photodegradation phenomenon and the thermal stability are also referred to in these examples, the relationship between the change in the layer thickness direction of fluorine and the photoelectric conversion efficiency, the relationship between the layer thickness direction of hydrogen, and the vibration deterioration. The relationship is not mentioned. Further, in these examples, a good-quality doping layer was obtained, but a photovoltaic element having high photoelectric conversion efficiency has not been obtained yet.

In the above conventional photovoltaic device, when the MWPCVD method is used for both formation of the i-type layer and formation of the doping layer, recombination of photoexcited carriers near the p / i interface and the n / i interface. It is desired to improve the open circuit voltage and the carrier range of holes.

Further, the doping layer and the i-type layer are formed by MWPC.
The photovoltaic element formed by the VD method is desired to further reduce the decrease in photoelectric conversion efficiency when the photovoltaic element is irradiated with light.

Further, the doping layer and the i-type layer are MWP.
The photovoltaic element formed by the CVD method has a problem that there is strain near the interface between the doping layer and the i-type layer, and the photoelectric conversion efficiency decreases (vibration deterioration) when placed in an environment where vibration occurs for a long time.

Further, in the above photovoltaic element, the photodegradation and the vibration degradation were remarkable when it was placed in a high temperature environment for a long time.

Further, in the above-mentioned photovoltaic element, photodegradation and vibration degradation were remarkable when it was placed in a high humidity environment for a long period of time.

Furthermore, in the above photovoltaic element, when a forward bias is applied and the device is placed in the above environment, photodegradation and vibration degradation are remarkable.

Further, the photovoltaic element containing a large amount of alkali metal has a problem that the photoelectric conversion efficiency is extremely low.

Further, the non-single-crystal silicon-based semiconductor layer containing fluorine has a problem that the layer is easily peeled off as compared with a layer containing no fluorine.

[0018]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a photovoltaic element which solves the above-mentioned problems of the prior art. That is, it is an object of the present invention to provide a photovoltaic element with improved photoelectric conversion efficiency in the conventional photovoltaic element with improved deposition rate.

Another object of the present invention is to provide a photovoltaic element which suppresses optical deterioration and vibration deterioration.

A further object of the present invention is to suppress optical deterioration and vibration deterioration of the photovoltaic element in a high temperature environment.

A further object of the present invention is to suppress optical deterioration and vibration deterioration of the photovoltaic element in a high humidity environment.

A further object of the present invention is to apply a forward bias to the photovoltaic element to suppress photodegradation and vibration degradation when placed in the above environment.

A further object of the present invention is to provide a photovoltaic element in which the semiconductor layer does not peel off even when the photovoltaic element is placed in the above environment.

Still another object of the present invention is to provide a photovoltaic device having excellent productivity.

Still another object of the present invention is to provide a power generation system using a photovoltaic element that achieves the above object.

[0026]

The present invention has been made in order to solve the conventional problems and achieve the above object, and as a result,
The photovoltaic element of the present invention has been found,
It is configured by laminating a p-type layer, an i-type layer, and an n-type layer made of a non-single-crystal silicon semiconductor material containing hydrogen, and the i-type layer contains an alkali metal and is formed by a microwave plasma CVD method. In the photovoltaic element, the alkali metal and hydrogen contents of the i-type layer change smoothly in the layer thickness direction, and at least one of the p-type layer and the n-type layer is formed by a microwave plasma CVD method. Layer (MW
And a layer formed by an RF plasma CVD method (RF doping layer), and the RF doping layer is disposed so as to be sandwiched between the MW doping layer and the i-type layer. It is characterized by that.

Further, the photovoltaic element of the present invention comprises a p-type layer made of a non-single crystal silicon semiconductor material containing hydrogen,
In a photovoltaic device formed by laminating an i-type layer and an n-type layer, wherein the i-type layer contains an alkali metal and is formed by a microwave plasma CVD method, the i-type layer includes germanium, tin and carbon. The content of germanium and tin, including at least one of the above, changes smoothly in the layer thickness direction, and the position where the maximum content is maximum deviates from the central position of the i-type layer to the p-type layer, and the carbon content is Is changed smoothly in the layer thickness direction and the position where the content is the minimum is p from the center position of the i-type layer.
The i-type layer deviating from the mold layer, and at least one of the p-type layer and the n-type layer is a microwave plasma CV.
It has a laminated structure of a layer formed by the D method (MW doping layer) and a layer formed by the RF plasma CVD method (RF doping layer), and the RF doping layer is the MW doping layer and the i layer. It is characterized in that it is arranged so as to be sandwiched between mold layers.

Further, the photovoltaic element of the present invention is a p-type layer made of a non-single-crystal silicon semiconductor material containing hydrogen,
In a photovoltaic device formed by laminating an i-type layer and an n-type layer, the i-type layer containing an alkali metal and formed by a microwave plasma CVD method, the i-type layer serves as a donor and controls valence electrons. Is an i-type layer containing both a valence electron control agent serving as an acceptor and an acceptor, and at least one layer of the p-type layer and the n-type layer is microwave plasma CVD.
And a layer (MW doping layer) formed by the RF plasma CVD method and a layer structure (RF doping layer) formed by the RF plasma CVD method, wherein the RF doping layer is the MW doping layer and the i-type layer. It is characterized by being arranged so as to be sandwiched between layers.

Further, a desirable mode of the present invention is the above photovoltaic device, which has an i-type layer (RF-i layer) formed by an RF plasma CVD method between the i-type layer and the RF doping layer. is there.

A preferred form of the present invention is the above-mentioned RF-i.
In the above photovoltaic element, the layer contains both a valence electron control agent serving as a donor and a valence electron control agent serving as an acceptor.

A preferred form of the present invention is the i-type layer,
At least one layer of the RF-i layer, the RF doping layer, and the MW doping layer contains fluorine, and the fluorine content is such that the fluorine content changes smoothly in the layer thickness direction.

A desirable mode of the present invention is the above-mentioned i-type layer,
At least one layer of the RF-i layer, the RF doping layer, and the MW doping layer is the above-mentioned photovoltaic device having the minimum fluorine content in the vicinity of the interface of at least one of the layers.

A preferred form of the present invention is the i-type layer,
At least one layer of the RF-i layer, the RF doping layer, and the MW doping layer is the above-mentioned photovoltaic element having the maximum hydrogen content in the vicinity of the interface of at least one of the layers.

A preferred embodiment of the present invention is the RF-i.
The photovoltaic element according to claim 1, wherein the alkali metal is contained in the layer, the RF doping layer, and the MW doping layer.

Further, a desirable mode of the present invention is the above photovoltaic element, in which the content of the alkali metal is minimum near at least one interface of the layer containing the alkali metal.

A desirable mode of the present invention is the above photovoltaic element, wherein the alkali metal is at least one element selected from lithium, sodium and potassium.

Further, a desirable mode of the present invention is the photovoltaic element, wherein the i-type layer and / or the RF-i layer contains tin, and the layer is made of amorphous silicon tin (a-SiSn). is there.

Further, a desirable mode of the present invention is the above-mentioned i-type layer,
The content of the valence electron control agent that serves as a donor or the content of the valence electron control agent that serves as an acceptor contained in the RF-i layer, the RF doping layer, and the MW doping layer changes in the layer thickness direction. The photovoltaic element has the maximum content in the vicinity of the interface.

A desirable mode of the present invention is the i-type layer,
In the above photovoltaic element, at least one of the RF-i layer, the MW doping layer, and the RF doping layer contains oxygen and / or nitrogen.

Further, the power generation system of the present invention monitors the voltage and / or current of the photovoltaic element and the photovoltaic element, and supplies electric power from the photovoltaic element to a storage battery and / or an external load. And a storage battery that stores electric power from the photovoltaic element and / or supplies electric power to an external load.

The present invention will be described in detail below with reference to the drawings.

FIG. 1A is a schematic explanatory view of the photovoltaic element of the present invention. In FIG. 1A, a photovoltaic element of the present invention is a substrate 101, an MWn-type layer 102 having an n-type conductivity type formed by the MWPCVD method, and an RFn having an n-type conductivity type formed by the RFPCVD method. Mold layer 103, M
An i-type layer 104 containing an alkali metal, formed by the WPCVD method, formed by the RFCVD method, an RF p-type layer 105 having a p-type conductivity type, formed by the MWPCVD method, p
Type conductivity type MWp type layer 106, transparent electrode 10
7, the collector electrode 108, and the like.

FIG. 1B is another example of a schematic explanatory view of the photovoltaic element of the present invention. In FIG. 1B, the photovoltaic element of the present invention is a substrate 111, n having an n-type conductivity type.
Mold layer 112, i-type layer 114, RFp-type layer 115, MWp
The mold layer 116, the transparent electrode 117, the collector electrode 118 and the like are included.

FIG. 1 (c) is another example of a schematic explanatory view of the photovoltaic element of the present invention. In FIG. 1C, the photovoltaic device of the present invention includes a substrate 121, a MWn type layer 122, and an RF.
n-type layer 123, i-type layer 124, p having p-type conductivity
The mold layer 125, the transparent electrode 127, the collector electrode 128 and the like are included.

In FIG. 1, the n-type layer and the p-type layer are RFCVD.
Formed by the RFPCVD method or the MWPCVD method.
It is desirable to form it by the method.

Further, in addition to the photovoltaic element having the pin structure as shown in FIG. 1, the n-type layer and the p-type layer are laminated in the opposite order.
It may be an ip type photovoltaic element.

Further, in the pin type photovoltaic device as shown in FIG. 1, an i-type layer (RF-i) formed by the RFPCVD method between the doping layer and the i-type layer having a laminated structure.
A photovoltaic device as in FIG. 2 having layers).

Further, the doping layer having the laminated structure of the present invention is, for example, RFp type layer / MWp type layer / RFp type layer / i type layer, i type layer / RFn type layer / MWn type layer / RFn type layer. (RF / MW) _n / RF type may have a laminated structure composed of three or more layers, or MWp type layer / R
It may be a (MW / RF) _n type laminated structure such as Fp type layer / MWp type layer / RFp type layer / i type layer.

The photovoltaic element of the present invention is a pinpin.
It may be a stack of pin structures such as a structure or a pinpinpin structure.

The photovoltaic element of the present invention is a nipnip
It may be a stack of nip structures such as a structure or a nipnipnip structure.

In the photovoltaic device of the present invention, since the MWPCVD method is used when forming the MW doping layer and the i-type layer, the deposition rate is high and the throughput can be improved. The utilization efficiency can be improved and the productivity is excellent.

Further, in the photovoltaic element of the present invention, since the doping layer is formed by the MWPCVD method, a doping layer having good characteristics as a photovoltaic element can be obtained.
That is, the doping layer is excellent as a doping layer because it has good light transmittance, high electric conductivity, and low activation energy, and is particularly effective as a doping layer on the light incident side. Further, since it is formed by the MWPCVD method, a good-quality microcrystalline silicon-based semiconductor material or a good-quality non-single-crystal silicon-based semiconductor material with a wide band gap can be formed relatively easily, and the doping layer on the light incident side can be formed. Is effective as.

Further, in the photovoltaic element of the present invention, since the doping layer is formed by the MWPCVD method, it is possible to suppress the photodegradation of the photovoltaic element, especially the degradation of the open circuit voltage.

Although the detailed mechanism is unknown, it is considered as follows. It is generally believed that the dangling bonds generated by light irradiation become the recombination centers of carriers and deteriorate the characteristics of the photovoltaic device. MWPC
Doping layer formed by VD method (MW doping layer)
Is formed at a deposition rate of 2 nm / sec or more, the introduced valence electron control agent is not 100% activated,
Even if a dangling bond is generated, the inactive valence electron control agent terminates it, so that it is considered that the characteristics of the photovoltaic element, particularly the decrease in open circuit voltage, can be suppressed.

Further, since there is a doping layer (RF doping layer) formed by the RFPCVD method between the i-type layer formed by the MWPCVD method and the MW doping layer, the interface state can be reduced, and the photoelectric level can be reduced. The conversion efficiency can be improved. Although the detailed mechanism is unknown, it is considered as follows.

It is desirable that the RF doping layer is formed with a low power so that the gas phase reaction does not easily occur and the deposition rate is 1 nm / sec or less. As a result, the packing density is increased, and when the layer is laminated with the i-type layer, the interface state of each layer is reduced. In particular, when the deposition rate of the i-type layer is 5 nm / sec or more, the surface level of the i-type layer is not sufficiently relaxed immediately after the glow discharge is excited by microwaves or immediately after the glow discharge is stopped, so that the surface level is It is increasing.

By forming the i-type layer on the RF-doped layer having a low deposition rate, the initial film of the i-type layer immediately after the glow discharge is affected by the underlying layer, the packing density becomes high, and the dangling is increased. It is considered that the layer has few ring bonds and the surface level is reduced.

Further, by forming an RF doping layer having a low deposition rate on the surface of the i-type layer, the surface level of the i-type layer is reduced by annealing due to diffusion of hydrogen atoms which occurs at the same time when the RF doping layer is formed. It is thought that it is possible.

Further, the content of the valence electron control agent in the RF doping layer is set higher than that in the i-type layer and lower than the content of the valence electron control agent in the doping layer formed by the MWPCVD method. It is possible to improve the open circuit voltage and the fill factor of the electromotive force element.

In addition, the photovoltaic element of the present invention is less susceptible to vibration deterioration. Although the detailed mechanism of this is not clear, MW-doped layers and i having very different constituent element ratios
By providing the RF doping layer between the type layers, local flexibility is increased, local strain between the MW doping layer and the i-type layer can be relaxed, and the generation of defect levels due to the strain can be prevented. It is considered that it is possible to prevent the deterioration of the photoelectric conversion efficiency of the photovoltaic element even if it is placed under vibration for a long period of time. This is particularly effective when the hydrogen content is high at both interfaces of the RF doping layer.

In addition, the photovoltaic element of the present invention is resistant to photodegradation. Although the details of the mechanism are unknown, it is generally considered that many weak bonds exist near the interface of the doping layer, and the weak bonds are broken by light, which deteriorates the characteristics of the photovoltaic element.
In the case of the present invention, by introducing many valence electron control agents in the vicinity of the interface of the RF doping layer and / or the MW doping layer, even if dangling bonds are generated by light irradiation,
It is considered that they react with a non-activated valence electron control agent to compensate dangling bonds.

As a change pattern of the content of the valence electron control agent in the layer thickness direction of the doping layer, the following examples can be given as preferable examples. 13 (a), (b), and (c), (B content) represents the content of the valence electron control agent serving as an acceptor, and (P content) represents the content of the valence electron control agent serving as a donor. Show.

FIG. 13A shows an example in which the content is maximized at both interfaces of the doping layer and the content is steeply sloped at the interface on the light incident side. It is particularly effective for a photovoltaic device having an i-type layer having a small band gap.

FIG. 13B shows an example in which the content is maximum at the interface on the light incident side of the doping layer and minimum at the interface on the opposite side, and the content is steeply sloped on the light incident side. is there.

FIG. 13C shows an example in which the content is maximized at both interfaces of the doping layer and the content has a steep gradient on both interface sides. In particular, it is effective when light is incident from the p-type layer side. It is particularly effective for a photovoltaic device having an i-type layer made of a material having a large band gap.

Further, in the photovoltaic element of the present invention, the i-type layer contains an alkali metal, and the alkali metal content changes smoothly in the layer thickness direction. By doing so, it is possible to suppress optical deterioration and vibration deterioration when a forward bias voltage is applied to the photovoltaic element. The detailed mechanism is unknown, but it is considered as follows.

I made of a non-single crystal silicon semiconductor material
When the mold layer contains an alkali metal, the alkali metal donates electrons to the main constituent elements of the i-type layer, such as silicon, germanium, tin, and carbon, and ionizes. It is considered that the ionized alkali metal is relatively easy to move inside the i-type layer, and the ionized alkali metal is likely to collect in the weak electric field region generated by applying the forward bias. In addition, generally, when the internal electrolysis of the i-type layer is weak, photo-induced defects and vibration-induced defects are likely to occur, and photo-degradation and vibration-degradation tend to be strong. Therefore, in the present invention, by making the alkali metal content relatively large in the weak electric field region and as small as possible in the strong electric field region, the ionized alkali metal is bonded even if photo-induced defects and vibration deterioration occur. It is supposed to compensate. Further, it is desirable to reduce the content of the alkali metal as much as possible in the high electric field region where the photo-induced defects and the vibration-induced defects are unlikely to occur. It is considered that such a compensation mechanism in the weak electric field region does not appear by containing other elements. It is also possible that atomic alkali metals compensate for photo-induced defects and vibration-induced defects and become ionized. The above effect is particularly strong when the doping layer has a laminated structure as in the present invention. Further, the above effect is further enhanced when the hydrogen content and the fluorine content in the i-type layer change in the layer thickness direction as described below.

An example of a desirable change pattern of the alkali metal content of the i-type layer in the photovoltaic element of the present invention will be described below with reference to the drawings.

FIG. 3A shows an example in which the alkali content is rapidly changed in the p-type layer and the minimum content is on the p-type layer side inside the bulk. In this case, the change pattern of the hydrogen content in the layer thickness direction is preferably that shown in FIG. When light is incident from the n-type layer side in the nip-type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction. Further, it is particularly effective when the p / i interface is composed of a heterojunction.

FIG. 3B shows an example in which the p-type layer is slowly changed to the n-type layer side, and the minimum alkali metal content is at the interface with the n-type layer. In this case, the change pattern of the hydrogen content in the layer thickness direction is preferably that shown in FIG. When light is incident from the n-type layer side in the nip type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction.

In FIG. 3C, the p-type layer side of the i-type layer and n
This is an example in which the content of alkali metal is drastically changed on the mold layer side. In this case, the change pattern of the hydrogen content in the layer thickness direction is preferably that shown in FIG. p / i interface, n
It is particularly effective when the / i interface is composed of a heterojunction.

In the present invention, the content of the alkali metal changes in the layer thickness direction, but the maximum value (Cmax) of the content in a certain minute region is 5 × 10 ¹⁸ cm ^-3 or less and the minimum value (Cmax).
min) is preferably 5 × 10 ¹⁴ cm ⁻³ or more.

Although the effect of the i-type layer has been described above, changing the alkali metal content in the layer thickness direction can be applied to the RF doping layer, the MW doping layer, and the RF-i layer described later. Is.

In addition, in the photovoltaic element of the present invention, the hydrogen content of the i-type 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. 3A, a p-type layer of an i-type layer,
By increasing the hydrogen content on the n-type layer side and making the hydrogen content minimum on the p-type layer side inside the bulk, as shown in FIG. 4A, the band gap of the i-type layer is reduced. The maximum is on the p-type layer side and the n-type layer side, and the minimum value is on the p-type layer side inside the bulk. Therefore, on the p-type layer side of the i-type layer, the electric field in the conduction band is large, so that the electrons and holes are efficiently separated, and the recombination of electrons and holes near the interface between the p-type layer and the i-type layer. Can be reduced. In addition, it is possible to prevent electrons from being diffused back into the p-type layer. Furthermore i
Since the electric field of the valence band increases from the type layer toward the n-type layer, recombination of electrons and holes excited on the n-type layer side of the i-type layer can be reduced.

Further, by increasing the hydrogen content in the vicinity of the interface between the doping layer and the i-type layer, the defect level is compensated by hydrogen, so that the dark current (during reverse bias) due to hopping conduction through the defect level is reduced. However, the open circuit voltage and fill factor of the photovoltaic element can be improved.

Further, by containing a larger amount of hydrogen in the vicinity of the interface than in the interior of the bulk, it is possible to reduce internal stress such as strain due to abrupt changes in the constituent elements peculiar to the interface. As a result, it is possible to prevent the photoelectric conversion efficiency from being lowered even when it is left under vibration for a long time.

Further, it is particularly effective when the heterojunction (Si / SiGe, Si / SiC, etc.) is formed between the i-type layer and the doping layer. It is generally considered that many interfaces and internal stresses exist at the interface of the heterojunction. In the photovoltaic device of the present invention, by containing a large amount of hydrogen near the interface of the heterojunction, the interface state can be reduced and the internal stress can be relaxed.

It is generally known that increasing the hydrogen content in the i-type layer made of an amorphous silicon semiconductor material increases the band gap.

An example of a desirable change pattern of the hydrogen content of the i-type 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 below with reference to the drawings.

FIG. 3A shows an example in which the hydrogen content is rapidly changed on the p-type layer side as described above, and the minimum value of the content is on the p-type layer side inside the bulk. In this case, the band gap is as shown in FIG. 4A, and when light is incident from the p-type layer side, a high electric field near the interface between the p-type layer and the i-type layer and the n-type layer and the i-type layer are generated. The high electric field in the vicinity of the interface can be used more effectively, and the collection efficiency of electrons and holes photoexcited in the i-type layer can be improved.

When light is incident from the n-type layer side in the nip-type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction, and when the band gap of the i-type layer is small, Especially effective. Further, it is particularly effective when the p / i interface is composed of a heterojunction.

FIG. 3B shows an example in which the p-type layer is slowly changed to the n-type layer side and the minimum content is at the interface with the p-type layer. In this case, the band gap is as shown in FIG. 4B, the electric field of the valence band can be increased over the entire region of the i-type layer, and 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-type layer side in the nip type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction. Further, it is particularly effective when the band gap of the i-type layer is small.

In FIG. 3C, the p-type layer side of the i-type layer and n
This is an example in which the hydrogen content changes drastically on the mold layer side. In this case, the band gap becomes as shown in FIG.
The electric field in the conduction band can be increased on the p-type layer side of the mold layer, and in particular, back diffusion of electrons into the p-type layer can be suppressed. Further, the electric field in the valence band can be strengthened by the i-type layer and the n-type layer, and in particular, the back diffusion of holes into the n-type layer can be suppressed. Further, such a hydrogen content and a bandgap change pattern are particularly effective for a photovoltaic device having an i-type layer having a large bandgap. That is, when light is incident from the p-type layer side in FIG.
The i-type layer having a large bandgap cannot sufficiently absorb light, and the photoexcited carriers near the interface between the i-type layer and the n-type layer are not recombined and are separated by the strong electric field near the interface to improve the collection efficiency. Can be raised. Further, it is effective for a photovoltaic element having a light reflecting layer.
That is, in a photovoltaic device having a light reflecting layer, since light is incident from both layers, collection efficiency can be similarly improved. The carrier range for the above can be improved, and the fill factor can be improved. Furthermore, it is particularly effective when the photovoltaic element is used in an environment with large vibration. p / i interface, n /
It is particularly effective when the i interface is composed of a heterojunction.

The effect of the i-type layer has been described above. However, changing the hydrogen content in the layer thickness direction is
F doping layer, MW doping layer, RF-i described later
It can also be applied to layers.

In the present invention, photodegradation can be suppressed by incorporating both a valence electron control agent that serves as a donor and a valence electron control agent that serves as an acceptor into the i-type layer. Although the details of the mechanism are unknown, in the present invention, the valence electron control agent in the i-type layer is not 100% activated. As a result, even if weak bonds are broken and unbonded hands are generated by light irradiation, it is considered that these react with unactivated valence electron control agents to compensate unbonded hands.

Further, it is considered that there are many weak bonds especially near the interface of the i-type layer, and in the case of the present invention, a large amount of the valence electron control agent is distributed near the interface with the doping layer,
It is considered to compensate the dangling bonds.

Further, even when the intensity of light applied to the photovoltaic element is weak, the probability of trapping photoexcited electrons and holes is reduced because the defect level is compensated by the valence electron control agent. As described above, since the dark current during reverse bias is small, sufficient electromotive force can be generated.
As a result, excellent photoelectric conversion efficiency is exhibited even when the intensity of light applied to the photovoltaic element is weak.

In addition, the photovoltaic element of the present invention is less likely to have a decrease in photoelectric conversion efficiency even under long-term vibration. Generally, since the constituent elements are very different at the interface between the i-type layer and the doping layer, internal stress exists at the interface,
It is believed that vibrations form dangling bonds and reduce the photoelectric conversion efficiency. However, even if a dangling bond is generated by containing both the valence electron control agent serving as a donor and the valence electron control agent serving as an acceptor inside the i-type layer, the valence electron control agent is not activated. It is considered to react to compensate dangling bonds. Further, when the content of the valence electron control agent that serves as a donor and the content of the valence electron control agent that serves as an acceptor change smoothly in the layer thickness direction, and the content of the valence electron control agent increases near the interface , Especially effective. Further, a heterojunction (Si / SiGe, Si / SiC) is formed between the i-type layer and the doping layer.
Etc.) is particularly effective. Generally, it is considered that many interface states and internal stress exist at the interface of the heterojunction. In the photovoltaic element of the present invention, the interface state can be reduced by including a large amount of an inactive valence electron control agent near the interface of the heterojunction.

The following example shown in FIG. 5 can be given as a pattern of changes in the content of the valence electron control agent in the i-type layer with respect to the layer thickness direction. In FIG. 5, (B content) shows the content of the valence electron control agent which becomes an acceptor, and P content shows the content of the valence electron control agent which becomes a donor. In FIG. 5A, the content is maximized on the p-type layer side and the n-type layer side of the i-type layer.
The p-type layer inside the bulk of the p-type layer to be the minimum, p
This is an example in which the mold layer has a steep gradient of content. In particular, it is effective when light is incident from the p-type layer side. When light is incident from the n-type layer side in the nip-type photovoltaic element, the pattern may be reversed with respect to the layer thickness direction. Further, it is particularly effective for a photovoltaic device having an i-type layer having a small band gap.

In FIG. 5B, the i-type layer has a maximum content on the p-type layer side and a minimum content on the n-type layer side, and has a steep gradient of the content on the p-type layer side. Here is an example. In particular, it is effective when light is incident from the p-type layer side. When light is incident from the n-type layer side in the nip-type photovoltaic element, the pattern may be reversed with respect to the layer thickness direction. Further, it is particularly effective for a photovoltaic device having an i-type layer having a small band gap.

In FIG. 5C, the content is maximized on the p-type layer side and the n-type layer side of the i-type layer, and there is a steep gradient of the content on the p-type layer side and the n-type layer side. This is an example. Especially p
It is effective when light is incident from the mold layer side. When light is incident from the n-type layer side in the nip-type photovoltaic element,
The pattern may be reversed with respect to the layer thickness direction. Figure 5
The change pattern as shown in (c) is particularly effective for a photovoltaic device having an i-type layer made of a material having a large band gap. That is, in FIG. 5C, when light is incident from the p-type layer side, carriers are excited also on the n-type layer side, so it is desirable to increase the content of the valence electron control agent also in this region.

In the case of the i-type layer, it is preferable that the valence electron control agent serving as a donor and the valence electron control agent serving as an acceptor are contained so as to compensate each other. Such distribution of the valence electron control agent can be applied to each semiconductor layer.

It is generally known that increasing the germanium and / or tin content in the i-type layer made of an amorphous silicon semiconductor material reduces the band gap.

In the photovoltaic element of the present invention, the content of germanium and / or tin in the i-type 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. 6A, the content of germanium and / or tin is reduced on the p-type layer side and the n-type layer side of the i-type layer, and the content of germanium and / or tin is maximized. As shown in FIG. 7 (a), the band gap of the i-type layer is maximum on the p-type layer side and the n-type layer side, and the minimum is the p-type inside the bulk. It becomes the layer side. Therefore i
On the p-type layer side of the p-type layer, electrons and holes are efficiently separated due to a large electric field in the conduction band, and recombination of electrons and holes near the interface between the p-type layer and the i-type layer is reduced. be able to. In addition, it is possible to prevent electrons from being diffused back into the p-type layer. Further, since the electric field of the valence band increases from the i-type layer toward the n-type layer, recombination of electrons and holes excited on the n-type layer side of the i-type layer can be reduced.

Further, by reducing the content of germanium and / or tin near the interface between the doping layer and the i-type layer, the open circuit voltage and fill factor of the photovoltaic element can be improved.

Further, by containing less germanium and / or tin in the vicinity of the interface than in the interior, it is possible to reduce the internal stress caused by the abrupt change of the constituent elements peculiar to the interface. As a result, it is possible to prevent the photoelectric conversion efficiency from being lowered even when it is left under vibration for a long time. Moreover, it is particularly effective when the heterojunction (Si / SiGe, SiC / SiGe, etc.) is formed between the i-type 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 germanium and / or tin near the interface of the heterojunction, flexibility near the hetero interface can be increased, internal stress can be relaxed, and interface level can be reduced. it can.

Hereinafter, with reference to the drawings, an example of a desirable change pattern of the germanium or / and tin content of the i-type layer in the photovoltaic element of the present invention, which is considered from the change of the band gap in the layer thickness direction explain.

In FIG. 6A, as described above, the content of germanium and / or tin is drastically changed on the p-type layer side, and the maximum value of the content is on the p-type layer side inside the bulk. . In this case, the band gap is as shown in FIG. 7A, and when light is incident from the p-type layer side, the band gap becomes i.
The high electric field in the vicinity of the interface of the type layer and the high electric field in the vicinity of the interface between the n-type layer and the i-type layer can be used more effectively, and the collection efficiency of electrons and holes photoexcited in the i-type layer is improved. be able to. When light is incident from the n-type layer side in the nip-type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction. Further, it is particularly effective when the band gap of the i-type layer is small.

FIG. 6B shows an example in which the p-type layer side is slowly changed to the n-type layer side, and the maximum content is at the interface with the p-type layer. In this case, the band gap is shown in FIG.
Thus, the electric field in the valence band can be increased over the entire region of the i-type layer, the carrier range for holes can be particularly improved, and the fill factor can be improved. In the nip type photovoltaic element,
When light is incident from the mold layer side, the change pattern may be reversed with respect to the layer thickness direction. Further, it is particularly effective when the content of germanium and / or tin in the i-type layer is relatively large.

In FIG. 6C, the p-type layer side of the i-type layer and n
This is an example in which the content of germanium and / or tin changes rapidly on the mold layer side. In this case, the band gap is as shown in FIG. 7C, and the electric field of the conduction band can be strengthened on the p-type layer side of the i-type layer, and in particular, the back diffusion of electrons to the p-type layer is suppressed. You can Further, the electric field in the valence band can be strengthened on the i-type layer side and the n-type layer side, and in particular, back diffusion of holes into the n-type layer can be suppressed. Further, it is particularly effective for a photovoltaic device having an i-type layer having a relatively low germanium and / or tin content. That is, when light is incident from the p-type layer side in FIG. 7C, the i-type layer having a large band gap cannot sufficiently absorb the light,
The photoexcited carriers in the vicinity of the interface between the i-type layer and the n-type layer are not recombined and are separated by the strong electric field in the vicinity of the interface, so that the 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 reflecting layer, since light is incident from both layers, collection efficiency can be similarly improved.

Further, it is generally known that the band gap increases as the carbon content in the i-type layer made of an amorphous silicon semiconductor material increases.

In the photovoltaic element of the present invention, the carbon atom content of the i-type 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. 8A, the inside of the bulk is defined by increasing the carbon atom content on the p-type layer side and the n-type layer side of the i-type layer and minimizing the carbon atom content. By providing it on the p-type layer side, the band gap of the i-type layer becomes maximum on the p-type layer side, the n-type layer side, and the minimum is on the p-type layer side inside the bulk, as shown in FIG. 9A. Therefore, on the p-type layer side of the i-type layer, the electric field in the conduction band is large, so that the electrons and holes are efficiently separated, and the recombination of electrons and holes near the interface between the p-type layer and the i-type layer. Can be reduced. In addition, it is possible to prevent electrons from being diffused back into the p-type layer. Further, since the electric field of the valence band increases from the i-type layer toward the n-type layer, recombination of electrons and holes excited on the n-type layer side of the i-type layer can be reduced.

By including more carbon atoms in the vicinity of the interface than in the interior, it is possible to reduce the internal stress caused by the abrupt change of the constituent elements peculiar to the interface. As a result, it is possible to prevent the photoelectric conversion efficiency from being lowered even when it is left under vibration for a long time. It is particularly effective when the junction with the doping layer is a homojunction.

Hereinafter, with reference to the drawings, an example of a desirable change pattern of the carbon atom content of the i-type layer in the photovoltaic element of the present invention, which is considered from the change of the band gap in the layer thickness direction, will be described.

In FIG. 8 (a), as described above, the content of carbon atoms is drastically changed on the p-type layer side, and the content is minimized on the p-type 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-type layer side, a high electric field near the interface between the p-type layer and the i-type layer and an interface between the n-type layer and the i-type layer. The high electric field in the vicinity can be used more effectively, and the collection efficiency of electrons and holes photoexcited in the i-type layer can be improved.
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, it is particularly effective when the i-type layer contains relatively few carbon atoms.

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

In FIG. 8C, the p-type layer side of the i-type layer and n
This is an example in which the content of carbon atoms is drastically changed on the mold layer side. In this case, the band gap is as shown in FIG. 9C, and the electric field of the conduction band can be strengthened on the p-type layer side of the i-type layer, and in particular, the back diffusion of electrons to the p-type layer is suppressed. You can Further, the electric field in the valence band can be strengthened on the i-type layer side and the n-type layer side, and in particular, back diffusion of holes into the n-type layer can be suppressed. In addition, the content of carbon atoms is relatively large i
It is particularly effective for a photovoltaic device having a mold layer. That is, in FIG. 9C, when light is incident from the p-type layer side, the i-type layer having a large band gap cannot sufficiently absorb the light, and photoexcited carriers near the interface between the i-type layer and the n-type layer are recombined. Without being carried out, they are separated by the strong electric field in the vicinity of this interface, and the 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 reflecting layer, since light is incident from both layers, collection efficiency can be similarly improved.

In the photovoltaic device of the present invention, the i-type layer, the MW doping layer, the RF doping layer, and the RF-i layer were made to contain fluorine, so that the photovoltaic device was placed in a high temperature environment for a long time. In this case, light deterioration and vibration deterioration can be suppressed.

In addition, it is possible to suppress photodegradation and vibration degradation when the photovoltaic element is left in a high humidity environment for a long time.

In addition, it is possible to suppress photodegradation and vibration degradation when the photovoltaic element is left in an environment of high temperature and high humidity for a long period of time.

Although the details of the mechanism are unknown, the electric energy of the fluorine atom is very large, and the binding energy between the fluorine atom and the silicon atom is large. Therefore, it is considered that a semiconductor layer that is thermally and mechanically stable and chemically stable can be obtained.

Further, like hydrogen, fluorine can terminate dangling bonds in the semiconductor layer, so that the defect level can be reduced. Further, since the atomic radius is very small like hydrogen, even when contained in the semiconductor layer, structural strain is not induced.

In the present invention, it is preferable that a small amount of fluorine be contained near the interface of the semiconductor layer. As will be described later, in the photovoltaic device of the present invention, a large amount of hydrogen is contained in the vicinity of the interface of the semiconductor layer to relax the structural strain. In order to keep the packing density of the semiconductor layer high, it is considered desirable to reduce the fluorine content in the vicinity of the interface where the hydrogen content is increased. By doing so, the level induced by the bond between hydrogen and fluorine in the semiconductor or by the reduction of the mutual distance can be reduced.

Further, by including fluorine in the doping layer, the doping efficiency can be improved and the light transmittance can be improved, so that the photoelectric conversion efficiency can be improved. In addition, since the microcrystalline silicon semiconductor material can be obtained with relatively low power by including fluorine in the doping layer, the doping layer made of the microcrystalline silicon semiconductor material is formed without adversely affecting the base layer. It is possible to reduce the interface state. Therefore, the photoelectric conversion efficiency can be improved.

With the photoelectric conversion efficiency of the present invention, since the MW doping layer is formed by the MWPCVD method, a particularly good quality doping layer can be obtained.

Further, in the photovoltaic element of the present invention, since the doping layer containing fluorine has a laminated structure, the effect of containing fluorine (suppression of photodegradation and vibration degradation under high temperature and high humidity environment) is obtained. ) Can be further exerted. Further, the semiconductor layer is not peeled off even when the photovoltaic element is placed in the above environment.

Hereinafter, an example of a desirable change pattern of the fluorine content of the i-type layer in the photovoltaic element of the present invention will be described with reference to the drawings.

FIG. 10A shows an example in which the fluorine content is drastically changed on the p-type layer side and the maximum content is on the p-type layer side inside the bulk. In this case, the change pattern of the hydrogen content in the layer thickness direction is preferably that shown in FIG.
When light is incident from the n-type layer side in the nip-type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction. Further, it is particularly effective when the p / i interface is composed of a heterojunction.

FIG. 10B is an example in which the maximum value of the fluorine content is slowly changed from the p-type layer side to the n-type layer side, and is at the interface with the p-type layer. In this case, the change pattern of the hydrogen content in the layer thickness direction is preferably that shown in FIG. When light is incident from the n-type layer side in the nip type photovoltaic element, the change pattern may be reversed with respect to the layer thickness direction.

FIG. 10C shows an example in which the fluorine content changes abruptly on the p-type layer side and the n-type layer side of the i-type layer. In this case, the change pattern of the hydrogen content in the layer thickness direction is preferably that shown in FIG. p / i interface, n /
It is particularly effective when the i interface is composed of a heterojunction.

The effect of the i-type layer has been described above. However, changing the fluorine content in the layer thickness direction is effective for the RF doping layer, the MW doping layer, and the RF-type layer described later.
It is also applicable to the i layer.

Further, in the photovoltaic element of the present invention, the slope of the tail state of the valence band of the i-type layer is an important factor that influences the characteristics of the photovoltaic element, and the tail at the minimum bandgap. It is preferable that the slope from the state to the slope of the tail state at the maximum band gap is smoothly continuous.

In the photovoltaic device of the present invention, the photoelectric conversion efficiency can be further improved by providing the i-type layer (RF-i layer) formed by the RFPCVD method between the RF doping layer and the i-type layer. It is a thing.

For example, in FIG. 2A, FIG.
The RF-i layer is provided between the RF p-type layer and the i-type layer. In addition, in FIG. 2B, RFn of FIG.
An RF-i layer is provided between the mold layer and the i-type layer. In addition, in FIG. 2C, the RF n-type layer of FIG.
An RF-i layer is provided between the mold layers and between the RF p-type layer and the i-type layer.

It is preferable that the RF-i layer is formed with low power in which vapor phase reaction does not easily occur and the deposition rate is 1 nm / sec or less. As a result, the packing density of the RF-i layer is increased, and when the RF-i layer is laminated with the i-type layer, the interface level of the i-type layer and the interface level of the doping layer are reduced. is there. In particular, when the i-type layer is deposited by the MWPCVD method at a deposition rate of 5 nm / sec or more, the vicinity of the surface of the i-type layer is sufficiently relaxed immediately after the glow discharge is started or stopped by the microwave. The interface states are very large because they are not.

By forming the i-type layer on the RF-i layer, the i-type layer immediately after the discharge start excitation is affected by the base, the packing density is increased, and the dangling bond is reduced. Therefore, it is considered that the surface level has decreased.

By forming the RF-i layer on the surface of the i-type layer, the surface level of the i-type layer can be reduced by annealing due to diffusion of hydrogen which occurs at the same time when the RF-i layer is formed. It is considered to be a thing.

Photodegradation can be suppressed by incorporating both a valence electron control agent as a donor and a valence electron control agent as an acceptor into the RF-i layer. Although the details of the mechanism are unknown, and in the case of the present invention, both the valence electron control agent serving as a donor and the valence electron control agent serving as an acceptor are contained in the RF-i layer, and they are 100% activated. Absent. As a result, even if dangling bonds are generated by light irradiation, it is considered that they react with the unactivated valence electron control agent to compensate dangling bonds.

In addition, the photovoltaic element of the present invention is such that the photoelectric conversion efficiency is unlikely to drop even if it is left under vibration for a long period of time. Although the detailed mechanism is unknown, by adding a large amount of hydrogen in the vicinity of the interface where the constituent element ratios are very different, it is possible to relax the internal stress that is often present in the vicinity of the interface and prevent the generation of defect levels. It is considered possible. Further, the valence electron control agent serving as a donor and the valence electron control agent serving as an acceptor, which are contained in large amounts in the vicinity of the interface, are not 100% activated, and even if the bond is broken by vibration, the valence electron control agent is not activated This is to compensate unbonded hands. The change pattern of the valence electron control agent is shown in FIG. 13 (a), FIG. 13 (b), and FIG.
The example of 3 (c) is mentioned as a suitable example.

Further, tin (Sn) may be contained in the i-type layer and / or the RF-i layer, and the layer may be composed of amorphous silicon tin (a-SiSn). Sn atoms can be covalently bonded to silicon (Si) atoms to obtain an amorphous silicon-based semiconductor material having a small bandgap, and compared with the Ge atom content of amorphous silicon-germanium (a-SiGe). The same band gap can be obtained with a small Sn content. Therefore, the method of a-SiSn is a-S
It is considered that a semiconductor having a narrow band gap can be formed with less structural disorder as compared with iGe. Furthermore, although Sn atoms have a larger covalent radius than Ge atoms, they are considered to be able to reduce structural strain when alloyed with Si atoms because they have more metallic properties.

The band gap of a-SiSn suitable for the present invention is 1.30 to 1.65 eV, and the Sn content is preferably 0.1 to 30%. The hydrogen content is preferably 0.1 to 30%, and the proportion of hydrogen bonded to Sn is preferably 1 to 40%.

The structure of a-SiSn suitable for the present invention contains microvoids and is distributed so that the relationship between the radius of the microvoids and the number of microvoids is a fractal relationship. is there. The ratio of microvoids deposited is preferably 0.5 to 3%. Although the reason is still unclear due to the distribution of the microvoids in this way, photodegradation can be suppressed as compared with a-SiGe.

At least one of the i-type layer, the RF-i layer, the MW doping layer and the RF doping layer may contain oxygen and / or nitrogen atoms. A small amount (1%) of oxygen or / and nitrogen atoms in the i-type layer and RF-i layer
By virtue of being included in the following), vibration deterioration of the photovoltaic element can be suppressed. The detailed mechanism is unknown, but by adding a trace amount, i-type layer, R
It is considered that the internal stress of the F-i layer can be relaxed. Furthermore, by including it in the RF-i layer, it is possible to prevent back diffusion of electrons or holes and improve the photoelectric conversion efficiency of the photovoltaic element. Further, by containing a small amount (1% or less) in the MW doping layer and the RF doping layer, the stress inside the layer can be relaxed and vibration deterioration can be suppressed. Further, by containing a large amount (1% or more), the open circuit voltage of the photovoltaic element can be improved. Preferably, the content of oxygen and / or nitrogen atoms changes in the layer thickness direction. As a preferable change mode, the content is large near one interface.

Although the photovoltaic element having the pin structure has been described above, the photovoltaic element in which the pin structure such as the pinpin structure or the pinpinpin structure is laminated, or ni.
The present invention can also be applied to a photovoltaic device in which a nip structure such as a pnip structure or a nipnipnip structure is laminated.

In the case of such a stacked photovoltaic element, n
RFn type layer / MWn type layer / RFp so that the layers formed by the MWPCVD method at the p junction (pn junction) are not continuous.
Type layer / MWp type layer / RFp type layer or RFn type layer /
MWn type layer / RFn type layer / RFp type layer / MWp type layer / R
It is desirable to form a junction having a structure such as an Fp type layer.

FIG. 11 is a schematic explanatory view of a deposition apparatus suitable for forming a semiconductor layer made of a non-single crystal silicon semiconductor material of the photovoltaic element of the present invention. The deposition device 40
0 is a deposition chamber 401, a vacuum gauge 402, an RF power source 403, a substrate 404, a heater 405, a waveguide 406, a conductance valve 407, an auxiliary valve 408, a leak valve 4.
09, bias electrode 410, gas introduction tube 411, applicator 412, dielectric window 413, sputtering power source 41
4, shutter 415, target shutter 417,
Target electrode 418, a microwave power source (not shown),
It consists of a vacuum exhaust pump and a source gas supply device. The raw material gas supply device (not shown) includes a raw material gas cylinder, a valve, and a mass flow controller.

The photovoltaic element of the present invention is manufactured as follows.

First, the substrate 404 is brought into close contact with the heater 405 installed in the deposition chamber 401 shown in FIG.
Sufficiently evacuated to below 0 ^-5 Torr. A turbo molecular pump or an oil diffusion pump is suitable for this exhaust. After exhausting the interior of the deposition chamber sufficiently, H ₂ , He, A
A gas such as r is introduced into the deposition chamber so that the pressure in the deposition chamber is almost the same as when the raw material gas for semiconductor formation is flown,
Turn on the heater 405 and set the substrate to 100-500.
Heat to ℃. 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 raw material gas for forming the semiconductor layer, which is introduced into the deposition chamber, is appropriately determined by the deposition in the deposition chamber and the desired deposition apparatus.

When the semiconductor layer is formed by the MWPCVD method, the pressure during the formation of the semiconductor layer is a very important factor, and the optimum pressure in the deposition chamber is 0.5 to 50 mTorr.
Is preferred.

The MW power introduced into the deposition chamber is an important factor. The MW power is appropriately determined depending on the flow rate of the source gas introduced into the deposition chamber, but a preferable range is 0.005 to 1 W / cm ³ . The preferable frequency range of MW power is 0.5 to
10 GHz is mentioned. A frequency near 2.45 GHz is particularly suitable. Further, in order to form a reproducible semiconductor layer and to maintain a stable glow discharge for several hours to several tens of hours, the frequency stability of the MW power is very important. It is preferable that the frequency variation is within ± 2%. Further, the ripple of the microwave is preferably within ± 2%. The MW power generated from such a microwave power source (not shown) is applied to the waveguide 4
06 transmission from the applicator 412 to the dielectric window 4
It is introduced into the deposition chamber via 13. In this state, the source gas is decomposed for a desired time to form a semiconductor layer having a desired layer thickness on the substrate. After that, the introduction of MW power is stopped, the deposition chamber is evacuated, and the substrate is taken out from the deposition chamber after being sufficiently purged with a gas such as H ₂ , He or Ar. The dielectric window is made of a material that transmits microwaves well, such as alumina ceramics, quartz, or boron nitride.

As a method of incorporating an alkali metal into the semiconductor layer, as shown in FIG. 11, a target electrode 418, to which a sputtering target 416 is closely attached, is installed in a deposition chamber, and a target power source 4 is attached to the target electrode.
14 is connected. Then, when forming the i-type layer, by applying DC voltage or RF power to the target electrode,
The i-type layer is made to contain a desired alkali metal by sputtering a target made of an alkali metal compound. When the target made of the alkali metal compound is conductive, DC voltage or R is applied to the target electrode.
F power is applied and RF power is applied if non-conductive.

As another method for containing an alkali metal in the semiconductor layer, the target and the target electrode are removed from the inside of the deposition chamber shown in FIG. 11, and a gas containing an alkali metal element is introduced into the deposition chamber through a gas introduction pipe. MW above
It can also be contained in the i-type layer by the CVD method.

Another method for incorporating an alkali metal into the semiconductor layer is, as described in JP-A-61-255073, thermal diffusion from a substrate containing an alkali metal (in this case, quartz glass). There is also a way to
It is difficult to control the content in the layer thickness direction, which is inappropriate for the present invention.

When forming the i-type layer of the photovoltaic element of the present invention, RF power may be introduced into the deposition chamber together with MW power. In this case, the MW power to be introduced is preferably smaller than the MW power required for 100% decomposition of the source gas to be introduced into the deposition chamber, and the RF power to be introduced at the same time is larger than the MW power. desirable. A preferable range of RF power to be simultaneously introduced is 0.0
1 to W / cm ³ . A preferable frequency range of the RF power is 1 to 100 MHz. Especially 13.
56 MHz is optimal. Also, the fluctuation of RF frequency is ±
It is preferable that the waveform is smooth within 2%. It is appropriately selected depending on the area ratio of the area of the RF electrode for supplying RF power to the area of ground, but especially when the area of the RF electrode for supplying RF power is smaller than the area of ground, it is for supplying RF power. It is better to ground the self-bias (DC component) on the power supply side. Alternatively, a DC voltage may be applied to the bias electrode. A preferable range of the DC voltage is about 30 to 300V. Further, RF power and DC voltage may be applied to the bias electrode at the same time.

Although the details of the deposition mechanism of the above preferred method of depositing the i-type layer are unknown, it is considered as follows.

MW required for 100% decomposition of raw material gas
It is considered that an active species suitable for forming a semiconductor layer can be selected by causing a MW electric power lower than the electric power to act on the source gas and a high RF power to act on the source gas at the same time as the MW power. Furthermore, when the pressure in the deposition chamber when decomposing the source gas is 50 mTorr or less, it is considered that the gas phase reaction can be suppressed as much as possible because the mean free path of active species suitable for forming a good quality semiconductor layer is sufficiently long. To be And again the pressure in the deposition chamber is 50 mTorr
It is considered that in the state of r or less, the RF power has almost no effect on the decomposition of the source gas and controls the potential between the plasma in the deposition chamber and the substrate. That is, in the case of the MWPCVD method, the potential difference between the plasma and the substrate is small, but the RF
By introducing electric power at the same time as MW electric power, the potential difference between plasma and substrate (+ on plasma side, − on substrate side)
Can be increased. Since the plasma potential is positively high with respect to the substrate, active species decomposed by MW power are deposited on the substrate, and at the same time + ions accelerated by the plasma potential collide with the substrate and relax on the substrate surface. It is considered that the reaction is promoted and a good quality semiconductor layer is obtained. And it is particularly effective when the deposition rate is 5 nm / sec or more. Further, since RF has a high frequency unlike DC, the difference between the plasma potential and the substrate potential is determined by the distribution of ionized ions and electrons.

That is, the potential difference between the substrate and the plasma is determined by the synergy of ions and electrons. Therefore, there is an effect that spark is unlikely to occur in the deposition chamber.

As a result, stable glow discharge can be maintained for a long time of 10 hours or more.

In the ordinary RFPCVD method, fluorine-containing source gas (for example, SiF ₄ gas, GeF ₄ gas, C
The decomposition energy of F ₄ gas or the like is about 10 of the decomposition energy of the raw material gas containing hydrogen (for example, SiH ₄ gas, GeH ₄ gas, CH ₄ gas, etc.).

Therefore, since a large amount of energy is applied to the glow discharge, the underlying semiconductor layer may be adversely affected, but in the MWPCVD method, since the frequency of the electromagnetic wave originally applied is high, fluorine is contained at low power. The raw material gas can be decomposed, and it is effective as a means for forming a semiconductor layer containing fluorine. Furthermore, since the radicals of the raw material gas containing fluorine have a relatively long life, MWP
Since the CVD method can further lengthen the mean free path, the discharge space and the substrate surface can be easily separated without reducing the deposition rate. Furthermore, MWP
When a source gas containing fluorine is used in the CVD method, the stability of discharge is improved, and glow discharge can be maintained for a long time of 20 hours or more.

As a method of changing the alkali metal content contained in the semiconductor layer in the layer thickness direction, R which is applied to the target electrode when the alkali metal content is desired to be increased
The F power may be increased and the RF power applied to the bias electrode may be decreased where it is desired to reduce the alkali metal content.

Further, in the case of applying DC power, it is sufficient to apply a large negative DC voltage applied to the target electrode where the content of alkali metal is desired to be increased, and when the content of alkali metal is desired to be decreased. The DC voltage applied to the target electrode may be a small negative voltage.

When the semiconductor layer does not contain an alkali metal, the target shutter may be closed.

When the alkali metal is contained by the MWPCVD method or the RFPCVD method, the flow rate of the gas containing the alkali metal may be changed with time.

As a method of changing the hydrogen content contained in the semiconductor layer in the layer thickness direction, the RF power applied to the bias electrode is increased when the hydrogen content is desired to be increased,
The RF power applied to the bias electrode may be reduced where it is desired to reduce the hydrogen content.

Although the detailed mechanism is still unknown, when the RF power applied to the bias electrode is increased,
The plasma potential rises and hydrogen ions move toward the substrate,
It is considered that more hydrogen is contained in the semiconductor layer in order to accelerate further.

Further, in the case of applying DC power at the same time as RF power, it is sufficient to apply a large voltage of + polarity to the DC voltage applied to the bias electrode where it is desired to increase the hydrogen content, and the hydrogen content is reduced. If desired, the DC voltage applied to the bias electrode may be applied as a small voltage with positive polarity. Although the detailed mechanism is still unclear, increasing the DC power applied to the bias electrode raises the plasma potential and causes more hydrogen ions to accelerate toward the substrate, resulting in more of the i-type layer. It is considered to contain hydrogen.

Still another method for changing the hydrogen content contained in the semiconductor layer in the layer thickness direction is to provide a halogen lamp or a xenon lamp in the deposition chamber in the semiconductor layer forming method of the present invention. These lamps are flashed during the formation of the semiconductor layer to temporarily raise the substrate temperature. At that time, when the hydrogen content is desired to be reduced, the number of flushes per unit time is increased, the substrate temperature is temporarily raised, and where the hydrogen content is desired to be increased, the number of flushes per unit time is decreased. The substrate temperature may be temporarily lowered. It is considered that the desorption reaction of hydrogen from the surface of the semiconductor layer is activated by temporarily raising the substrate temperature.

As another method for changing the hydrogen content contained in the semiconductor layer in the layer thickness direction, a source gas containing fluorine and a source gas containing hydrogen are introduced at the time of forming the semiconductor layer, and the respective source gases are introduced. Should be changed over time. When it is desired to contain a large amount of hydrogen, a small amount of the raw material gas containing fluorine is allowed to flow, and where it is desired to contain a small amount of hydrogen, a large amount of the raw material gas containing fluorine is allowed to flow.

As a method of changing the valence electron control agent, carbon atom, germanium, tin, etc. contained in the semiconductor layer in the layer thickness direction, a valence electron control agent, carbon atom, germanium,
The flow rate of the raw material gas for containing tin may be changed with time.

As another method for changing the germanium and / or tin contained in the semiconductor layer in the layer thickness direction,
Increase the MW power to be introduced at the point where you want to increase the number of germanium or / and tin atoms.
Also, it is sufficient to reduce the MW power to be introduced where it is desired to reduce tin atoms. Although the detailed mechanism is still unknown, it is considered that the radical containing active germanium and / or tin is increased by increasing the MW power, and thus more germanium and / or tin atoms are contained. To be

As a method of changing the fluorine content contained in the semiconductor layer in the layer thickness direction, the gas containing fluorine may be changed with time when the semiconductor layer is formed. Where a large amount of fluorine is desired, a large amount of fluorine-containing gas is allowed to flow, and where a small amount of fluorine is desired, a small amount of fluorine-containing gas may be allowed to flow.

As another method for changing the fluorine content in the layer thickness direction, the hydrogen-containing gas may be changed with time when the semiconductor layer is formed. When a large amount of fluorine is desired to be contained, a small amount of hydrogen-containing gas is allowed to flow, and where a small amount of fluorine is desired to be included, a large amount of hydrogen-containing gas may be allowed to flow. It is considered that this is because the fluorine bonded to the surface of the semiconductor layer reacts with a radical containing hydrogen, the fluorine is extracted from the semiconductor layer, and the fluorine incorporated in the semiconductor layer is relatively reduced.

When the semiconductor layer is deposited by the RFPCVD method, the capacitive coupling type RFPCVD method is suitable.

By the RFPCVD method, a doping layer, RF-
When forming the i layer, the substrate temperature in the deposition chamber is 100 to 5
00 ° C., pressure 0.1 to 10 Torr, RF power 0.1.
01-5.0 W / cm ² , deposition equipment 0.1-2 nm /
The minimum condition is sec. R for a long time
In order to maintain the F glow discharge, it is desirable that the frequency fluctuation and the ripple of the RF power source are within 2%.

Further, US Pat. No. 4,400,409 discloses roll-to-roll (Roll to Ro).
A plasma CVD apparatus that continuously forms semiconductor layers, which employs the method of (ll), is disclosed. 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. It is said that a photovoltaic element having a pin junction can be continuously manufactured by continuously transporting the substrate in the longitudinal direction while forming a semiconductor layer. In the specification, in order to prevent the source gas for containing each valence electron control agent in the semiconductor layer from diffusing into another deposition chamber and mixing into another semiconductor layer,
A gas gate is used. Specifically, 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 flown into each separation passage to prevent mutual diffusion of the source gases. ing.

The alkali metals used in the present invention are lithium, sodium, potassium, rubidium and cesium,
Lithium, sodium and potassium having a small ionic radius are preferably used.

In the above semiconductor layer forming method, when the alkali metal is sputtered to be contained in the semiconductor layer, the following compounds or a mixture thereof are suitable as the target material. When the alkali metal is contained in the semiconductor layer by the MWPCVD method or the RFPCVD method, the following compounds are suitable as the source gas containing the alkali metal. For gasification, a compound that is liquid at room temperature can be obtained by encapsulating a compound in a liquid cylinder and bubbling with an inert gas such as He or Ar, and a compound that is solid at room temperature can be encapsulated in a liquid cylinder. , Heating the liquid cylinder to melt the compound,
It can be obtained by bubbling with an inert gas such as e or Ar.

Compounds for containing lithium in the semiconductor layer include LiI.3H ₂ O and LiClO ₄ 3H.
_{2 O, LiH 2 PO 4,} Li (s-C 4 H 9) , and the like.

To include sodium in the semiconductor layer
As the compound of Na₂O₂・ 8H₂O, Na₂SO_Four・ 1
0H₂O, NaHSO_Four・ H₂O, NaPH₂O₂・ H₂O,
Na ₂PHO₃・ 5H₂O, Na₂SiO₃・ 9H₂O etc.
You can

Compounds for containing potassium in the semiconductor layer include KF · 2H ₂ O, 2KI ₃ · H ₂ O and K
[ICl ₂ ] · H ₂ O, K [IBr ₂ ], K ₂ S · 5H
₂ O, KGa (SO ₄ ) ₂ .12H ₂ O (liquid) and the like.

As the compound for containing rubidium in the semiconductor layer, AlRb (SO ₄ ) ₂ .12H ₂ O and the like can be mentioned.

For containing potassium in the semiconductor layer
AlCs (SO_Four) ₂・ 12H₂O, C
rCs (SO_Four)₂・ 12H₂O etc. are mentioned.

In addition, the above MWPCVD method and RFPCVD
In the method of forming a semiconductor layer by the method, the following gas or a compound that can be gasified by bubbling is suitable as a source gas.

As a raw material gas for containing silicon atoms in the semiconductor layer, SiH ₄ (H includes deuterium D), SiX ₄ (X: halogen atom), SiX _n H _4-n
(N is an integer), Si ₂ X _n H _{6-n and the} like. Collectively referred to as "source gas (Si)". Especially SiH ₄ , Si
D ₄ , Si ₂ H ₆ , SiF ₄ and Si ₂ F ₆ are suitable.

Source gases for containing fluorine atoms in the semiconductor layer include F ₂ , SiF ₄ , Si ₂ F ₆ and Ge.
F ₄ , CF ₄ , C ₂ F ₆ , C ₂ ClF ₅ , CCl
₂ F ₂ , CClF ₃ , CHF ₃ , C ₃ F ₈ , NF ₃ , P
F ₅ , BF ₃ , SF _{4 and the} like can be mentioned. Collectively referred to as "source gas (F)". Especially SiF ₄ , GeF ₄ , C
F ₄ , PF ₅ and BF ₃ are suitable.

CH ₄ (H includes deuterium D) and C _n are used as a source gas for containing carbon atoms in the semiconductor layer.
H _{2n +} 2 (n is an _{integer), C n H 2n, CX} 4 (X is a halogen _{atom), C n X 2n + 2} , C n X 2n, C 2 H 2, C 6 H 6 and the like. Collectively referred to as "source gas (C)". CH ₄ , CD ₄ , C ₂ H ₂ and CF ₄ are particularly suitable.

The semiconductor layer was made to contain germanium.
GeH as a raw material gas for_Four(H includes deuterium D
Mu), Ge_nH_{2n + 2}, GeX_Four(X is a halogen atom) etc.
Is mentioned. Collectively referred to as "source gas (Ge)".
Especially GeH_Four, GeD_Four, GeF _FourIs suitable.

The source gas for containing tin atoms in the semiconductor layer is SnH ₄ (H includes deuterium D), S
n _n H _{2n + 2} , SnX ₄ (X is a halogen atom), SnR ₄
(R: alkyl group), SnX _n R _{4-n and the} like.
Collectively referred to as "source gas (Sn)". Especially SnH ₄ ,
SnD ₄ , Sn (CH ₃ ) ₄ are suitable.

Examples of the valence electron control agent introduced to make the conductivity type of the semiconductor layer p-type include Group III atoms (B, Al, Ga, In, Tl) of the periodic table, and the conductivity type is n. Examples of the valence electron control agent introduced for forming the type include Group V atom (P, As, Sb, Bi) and Group VI atom (S, Se, Te) in the periodic table.

A group III atom of the periodic table is introduced into the semiconductor layer.
As a raw material gas to enter, B ₂H₆, B_FourH_Ten,
B_FiveH₉, BF₃, BCl₃, B (CH₃)₃, B (C
₂H _Five)₃, AlCl₃, Al (CH₃)₃, GaCl
₃, InCl₃, TlCl₃Etc. can be mentioned.
Collectively referred to as "source gas (III)". Especially B
₂H ₆, B (CH₃)₃, B (C₂H_Five)₃, Al (C
H₃)₃, BF₃Is suitable.

PH ₃ , P ₂ H ₄ , and PH ₂ are used as the source gas for introducing the group V atom of the periodic table into the semiconductor layer.
I, PF ₃ , PF ₅ , PCl ₃ , PCl ₅ , PBr ₃ ,
PBr ₅ , PI ₃ , AsH ₃ , AsF ₃ , AsCl ₃ ,
AsBr ₃ , AsF ₅ , SbH ₃ , SbF ₃ , Sb
F ₅ , SbCl ₃ , SbCl ₅ , BiH ₃ , BiC
l ₃ , BiBr _{3 and the} like can be mentioned. Collectively referred to as "source gas (V)". Especially PH ₃ , AsH ₃ , P
F ₅ is suitable.

Source gases for introducing Group VI atoms of the periodic table into the semiconductor layer include H ₂ S, SF ₄ , and S.
F ₆ , CS ₂ , H ₂ Se, SeF ₆ , TeH ₂ , TeF
₆ , (CH ₃ ) ₂ Te, (C ₂ H ₅ ) ₂ Te, and the like. Collectively referred to as "source gas (VI)". Especially H ₂
S and H ₂ Se are suitable.

O ₂ , CO ₂ , CO, NO, NO ₂ , as a raw material gas for containing oxygen atoms in the semiconductor layer,
_{N 2 O, H 2 O,} CH 3 CH 2 OH, CH 3 OH , and the like. Collectively referred to as "source gas (O)". Especially O
₂ , NO is suitable.

For containing a nitrogen atom in the semiconductor layer
N as source gas₂, NO, NO ₂, N₂O, NH₃
Etc. Collectively referred to as "source gas (N)".
Especially N₂, NH₃Is suitable.

[0187] Further, these source gases are used as H ₂ , D ₂ , and H
It may be appropriately diluted with a gas such as e or Ar and introduced into the deposition chamber.

The configuration of the photovoltaic element of the present invention will be described in detail below. Substrate The substrate may be made of a conductive material alone, or may be one having a conductive layer formed on a support made of an insulating material or a conductive material. As the conductive material, for example, NiCr, stainless steel, Al, Cr, M
Examples thereof include metals such as o, Au, Nb, Ta, V, Ti, Pt, Pb and Sn, and alloys thereof. In order to use these materials as a support, it is preferable that the material has a sheet shape or a roll shape in which a long sheet is wound around a cylindrical body.

As the insulating material, polyester, polyethylene, polycarbonate, cellulose acetate,
Examples thereof include synthetic resins such as polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene and polyamide, or glass, ceramics and paper. In order to use these materials as a support, it is preferable that the material has a sheet shape or a roll shape in which a long sheet is wound around a cylindrical body. 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, in the case of glass, NiC is formed on the surface.
r, Al, Ag, Cr, Mo, Ir, Nb, Ta, V,
Ti, Pt, Pb, In₂O₃, ITO (In₂O₃+
SnO ₂), ZnO and other materials or alloys thereof.
Forming an electrical layer and using a synthetic resin sheet such as polyester film
If it is a gut, NiCr, Al, Ag, Pb, Z on the surface
n, Ni, Au, Cr, Mo, Ir, Nb, Ta, V,
Form a conductive layer made of a material such as Tl or Pt or its alloy
Made of stainless steel, NiCr, Al, Ag, C
r, Mo, Ir, Nb, Ta, V, Ti, Pt, Pb,
In₂O₃, ITO (In₂O₃+ SnO₂), ZnO
A conductive layer made of a material such as the above or an alloy thereof is formed. form
The vacuum deposition method, sputtering method, and screen method
It is formed by a screen printing method or the like. The surface shape of the support is smooth
The height of the mountain is unevenness with a maximum height of 300 to 1000 nm.
Is desirable.

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, the function as a support is sufficiently exerted. Can be made as thin as possible. However, it is usually 10 μm or more in terms of mechanical strength and the like in terms of manufacturing and handling of the support.

Preferred substrate forms in the photovoltaic element of the present invention are 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.

A more desirable substrate form in the photovoltaic element of the present invention is ZnO, Sn on the light reflection layer.
O ₂ , In ₂ O ₃ , ITO, TiO ₂ , CdO, Cd ₂
This is to form a conductive layer (reflection-increasing layer) made of SnO ₄ , Bi ₂ O ₃ , MoO ₃ , Na _x WO _3, or the like. Suitable methods for depositing the reflection-increasing layer include vacuum deposition method, sputtering method, CVD method, play method, spin-on method, dipping method and the like. As for the layer thickness of the reflection increasing layer, the optimum layer thickness varies depending on the refractive index of the material of the reflection increasing layer, but the preferable layer thickness range is 5
0 nm-10 micrometers is mentioned. Further, in order to texture the reflection enhancing layer, it is preferable to raise the substrate temperature at the time of forming the reflection enhancing layer to 200 ° C. or higher. MW doping layer (MWp type layer, MWn type layer) This layer is an important layer that influences the characteristics of the photovoltaic device.

The MW doping layer is composed of an amorphous silicon semiconductor material, a microcrystalline silicon semiconductor material, or a polycrystalline silicon semiconductor material. Amorphous (a
Abbreviated as −) as a silicon-based semiconductor material is aS
i, a-SiC, a-SiGe, a-SiGeC, a-
SiO, a-SiN, a-SiON, a-SiCON, etc. are mentioned. Microcrystalline (abbreviated as μc−) silicon-based semiconductor materials include μc-Si, μc-SiC, μc-
SiGe, μc-SiO, μc-SiGeC, μc-S
iN, μc-SiON, μc-SiOCN and the like can be mentioned. Polycrystalline (abbreviated as poly-) silicon-based semiconductor materials include poly-Si, poly-SiC, and po.
Examples include ly-SiGe.

In particular, a crystalline semiconductor material with little light absorption or an amorphous semiconductor layer with a wide bandgap is suitable for the MW doping layer on the light incident side. Specifically, a-Si
C, a-SiO, a-SiN, a-SiON, a-Si
CON, μc-Si, μc-SiC, μc-SiO, μ
c-SiN, μc-SiON, μc-SiOCN, po
Ly-Si and poly-SiC are suitable.

The amount of the valence electron control agent introduced to make the conductivity type p-type or n-type is 1000 ppm to 10 ppm.
% Is mentioned as a preferable range.

Further, the contained hydrogen (H, D) and fluorine serve to compensate dangling bonds and improve the doping efficiency. Hydrogen and fluorine content is 0.1-3
An optimum amount is 0 at%. Especially when the MW doping layer is crystalline, 0.01 to 10 at% can be mentioned as the optimum amount. Further, a preferable distribution form is one in which the hydrogen content on the interface side is large, and the hydrogen content in the vicinity of the interface is 1.1 to 3 times the content in the bulk as a preferable range. . In addition, a preferable distribution form is one in which the fluorine content is small on the interface side, and a preferable range is 0.3 to 0.9 times in the bulk.

The amount of oxygen and nitrogen atoms introduced is 0.1 ppm to
20%, 0.1ppm to 1% when contained in a trace amount
Is a preferable 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 100 Ωcm or less, and most preferably 1 Ωcm or less. Furthermore, the layer thickness is 1
50 nm is preferable and 3 to 30 nm is optimum.

Further, the source gases are H ₂ , D ₂ , He, A
It may be appropriately diluted with a gas such as r and introduced into the deposition chamber.

In particular, when forming a crystalline semiconductor material having a small light absorption or an amorphous semiconductor layer having a wide band gap, the source gas is diluted 2 to 100 times with a gas such as H ₂ , D ₂ and He. However, it is preferable to introduce a relatively high MW power. RF doping layer (RFp type layer, RFn type layer) This layer is an important layer that influences the characteristics of the photovoltaic device.

The RF doping layer is composed of an amorphous silicon semiconductor material, a microcrystalline silicon semiconductor material, or a polycrystalline silicon semiconductor material. Amorphous (a
Abbreviated as −) as a silicon-based semiconductor material is aS
i, a-SiC, a-SiGe, a-SiGeC, a-
SiO, a-SiN, a-SiON, a-SiCON, etc. are mentioned. Microcrystalline (abbreviated as μc−) silicon-based semiconductor materials include μc-Si, μc-SiC, μc-
SiGe, μc-SiO, μc-SiGeC, μc-S
iN, μc-SiON, μc-SiOCN and the like can be mentioned. Polycrystalline (abbreviated as poly-) silicon-based semiconductor materials include poly-Si, poly-SiC, and po.
Examples include ly-SiGe.

Particularly, for the RF doping layer on the light incident side, a crystalline semiconductor material with little light absorption or an amorphous semiconductor layer with a wide band gap is suitable. Specifically, a-Si
C, a-SiO, a-SiN, a-SiON, a-Si
CON, μc-Si, μc-SiC, μc-SiO, μ
c-SiN, μc-SiON, μc-SiOCN, po
Ly-Si and poly-SiC are suitable.

The amount of the valence electron control agent introduced to make the conductivity type p-type or n-type is preferably 800 ppm to 8%, and is preferably less than the amount of the MW doping layer. .

Further, the contained hydrogen (H, D) and fluorine function to compensate dangling bonds and improve the doping efficiency. Hydrogen and fluorine content is 0.1-2
An optimum amount is 5 at%. Especially when the RF doping layer is crystalline, 0.01 to 10 at% is mentioned as the optimum amount. Further, a preferable distribution form is one in which the hydrogen content on the interface side is large, and the hydrogen content in the vicinity of the interface is 1.1 to 3 times the content in the bulk as a preferable range. . A preferable distribution form is one in which the fluorine content is small on the interface side, and a preferable range is 0.3 to 9 times the content in the bulk.

The introduction amount of oxygen and nitrogen atoms is 0.1 ppm to
20%, 0.1ppm to 1% when contained in a trace amount
Is a preferable 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 100 Ωcm or less, and most preferably 1 Ωcm or less. Furthermore, the layer thickness is 1
50 nm is preferable and 5 to 20 nm is optimum.

In particular, when a crystalline semiconductor material having a small light absorption or an amorphous semiconductor layer having a wide band gap is formed, the source gas is diluted 2 to 100 times with a gas such as H ₂ , D ₂ and He. However, it is preferable to introduce a relatively high RF power. i-Type Layer In the photovoltaic device of the present invention, the i-type 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 i-type layer, and is composed of an amorphous silicon semiconductor material containing hydrogen. For example, a-Si, a-SiC, a-
SiGe, a-SiGeC, a-SiSn, a-SiS
nC, a-SiSnGe, a-SiSnGeC, etc. are mentioned.

As the i-type layer of the photovoltaic element of the present invention,
It contains silicon, hydrogen and an alkali metal, and the hydrogen content and the alkali metal content change smoothly in the layer thickness direction.

As the i-type layer of the photovoltaic element of the present invention,
A valence electron control agent (a group V atom or a group VI atom of the periodic table) which contains silicon, hydrogen and an alkali metal and serves as a donor; and a valence electron control agent (group III atom of the periodic table) which serves as an acceptor. Are contained together. A desirable form is that the valence electron control agent is increased on the p-type layer and n-type layer sides. The amount of introduction of each of the group V atom, the group VI atom and the group III atom of the periodic table introduced into the i-type layer is preferably 500 ppm or less. Further, it is preferable to contain a p-type valence electron control agent and an n-type valence electron control agent so as to compensate each other.

The i-type layer of the photovoltaic element of the present invention contains silicon, hydrogen and an alkali metal, contains germanium and / or tin atoms, and has a germanium or / and tin atom content. It changes smoothly in the layer thickness direction. The preferable range of the germanium or / and tin atom content is 1 to 50%, and the preferable range of the band gap is 1.3 to 1.7 eV.

The i-type layer of the photovoltaic element of the present invention contains silicon, hydrogen and an alkali metal and also contains carbon atoms, and the content of carbon atoms changes smoothly in the layer thickness direction. It is a thing. The preferable range of the carbon atom content is 1 to 50%, and the preferable range of the band gap is 1.
It is 8 to 2.2 eV. When it further contains germanium and / or tin atoms, the preferable band gap range is 1.5 to 2.0 eV.

Hydrogen (H, D) and fluorine contained in the i-type layer serve to compensate dangling bonds in the i-type layer and improve the product of carrier mobility and lifetime in the i-type layer. It is a thing. 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 optimum content of hydrogen and fluorine in the i-type layer is 1 to 30 at%. In particular, the one in which the hydrogen content is large on the interface side is mentioned as a preferable distribution form, and the range of 1.1 to 3 times in the bulk is mentioned as a preferable range. In addition, a preferable distribution form is one in which the fluorine content is small on the interface side, and a preferable range is 0.3 to 0.9 times in the bulk.

The amount of oxygen and nitrogen atoms introduced is 0.1 ppm to
1% is a suitable range.

The layer thickness of the i-type layer largely depends on the structure of the photovoltaic element (eg, single cell, tandem cell, triple cell) and the bandgap of the i-type layer, but is 0.05 to
The optimum layer thickness is 1.0 μm.

The i-type layer of the present invention has a deposition rate of 2.5 nm.
Even if it is increased above / sec, the tail state on the valence band side
It is a little, and the tilt of the tail state is 60 me.
V or less and not determined by electron spin resonance (ESR)
Bond density is 10¹⁷/ Cm ³It is the following.

The MWPCVD method is used to form the i-type layer,
It is desirable to use RF in the MWPCVD method as described above.
Power is introduced at the same time, and more preferably RF power and DC power are introduced at the same time in the MWPCVD method as described above.

When forming a-SiC having a wide band gap, it is preferable to dilute the raw material gas 2 to 100 times with a gas such as H ₂ , D ₂ and He to introduce a relatively high MW power. RF-i layer In the photovoltaic device of the present invention, the RF-i layer is an important layer for transporting photoexcited carriers.

The RF-i layer is slightly p-type and slightly n-type.
A mold layer can also be used and is composed of an amorphous silicon semiconductor material or a microcrystalline silicon semiconductor material. Examples of the amorphous silicon-based semiconductor material include a-Si and a.
-SiC, a-SiO, a-SiN, a-SiGe, a
-SiGeC, a-SiSn, a-SiSnC, etc. are mentioned. Examples of the microcrystalline silicon-based semiconductor material include μc-Si, μc-SiC, μc-SiGe, and μc-S.
iSn, μc-SiO, μc-SiN, μc-SiO
N, μc-SiOCN and the like can be mentioned.

As shown in FIG. 2A, the RF-i layer on the light incident side is a-Si, a-SiC, a-SiO, a-Si.
The open circuit voltage of the photovoltaic element can be improved by using a semiconductor material such as N.

As shown in FIG. 2B, the RF-i layer on the side opposite to the light incident side is a-Si, a-SiGe, a-Si.
By using a semiconductor material such as Sn, a-SiGeC, or a-SiSnC, the short-circuit current of the photovoltaic element can be improved.

Hydrogen (H, D) and fluorine contained in the RF-i layer serve to compensate dangling bonds in the RF-i layer, and are the product of carrier mobility and lifetime 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 in the RF-i layer is 1 to 30 at%. In particular, the one in which the hydrogen content is large on the interface side is mentioned as a preferable distribution form, and the range of 1.1 to 3 times the content in the bulk is mentioned as a preferable range. In addition, a preferable distribution form is one in which the fluorine content is low on the interface side, and a preferable range is 0.3 to 0.9 times the content in the bulk.

As another desirable form, a valence electron controlling agent (group V atom and / or group VI atom of the periodic table) serving as a donor and a valence electron controlling agent (group III atom of the periodic table) serving as an acceptor are used. Both are included. Further, it is preferable that a valence electron control agent serving as a donor and a valence electron control agent serving as an acceptor are contained so as to compensate each other.

Periodic Table No. III to be introduced into the RF-i layer
The introduction amount of each of the group atom, the group V atom, and the group VI atom is preferably 600 ppm or less.

The amount of oxygen and nitrogen atoms introduced is 0.1 ppm to
20%, 0.1ppm to 1% when contained in a trace amount
Is a preferable range.

The optimum layer thickness of the RF-i layer is 0.5 to 30 nm or less. The tail state on the valence band side is small, and the slope of the tail state is 5.
It is 5 meV or less, and the density of dangling bonds by electron spin resonance (ESR) is 10 ¹⁶ / cm ³ or less. Transparent electrode For the transparent electrode, indium oxide (In ₂ O ₃ ), soot oxide (SnO ₂ ), ITO (In ₂ O ₃ —SnO ₂ ) are suitable materials, and even if these materials contain fluorine. Good.

For the deposition of the transparent electrode, the sputtering method and the vacuum vapor deposition method are the optimal deposition methods.

In the case of depositing by the sputtering method, a target such as a metal target or an oxide target is appropriately combined and used.

In the case of depositing by the sputtering method, the substrate temperature is an important factor, and 20 ° C. to 600 ° C. is mentioned as a preferable range. When depositing a transparent electrode by a sputtering method, as a gas for sputtering,
An inert gas such as Ar gas may 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 in the discharge space is preferably 0.1 to 50 mTorr for effective sputtering. 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.
The range is from 01 to 10 nm / sec.

Suitable vapor deposition sources for depositing transparent electrodes in the vacuum vapor deposition method include metal tin, metal indium, and indium-tin alloy. 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 necessary 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 /
If it is larger than sec, a rough film is formed and the transmittance, the conductivity and the adhesion are lowered.

The layer thickness of the transparent electrode is preferably deposited under the conditions satisfying 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. Current collector electrode In order to allow more light to enter the i-type layer, which is a photovoltaic layer, and to efficiently collect the generated carriers in the electrode, the shape of the current collector electrode (the shape viewed from the light incident direction), and 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 collector electrode is Fe, Cr, Ni, Au, Ti, P
d, Ag, Al, Cu, AlSi, C (graphite)
Etc. are usually used, and Ag, Cu, Al, which have low specific resistance,
Metals such as Cr and C, or alloys thereof are suitable.

The layer structure of the collector electrode may be composed of a single layer or may be composed of a plurality of layers.

These metals are preferably formed by vacuum vapor deposition, sputtering, plating, printing or the like.

In the case of forming by a vacuum evaporation method, a mask having a shape of a collecting electrode is brought into close contact with the transparent electrode, and a desired metal evaporation 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 the 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. By letting
A 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 thickness of the cholera metal layer is from 10 nm to
0.5 mm is mentioned as a suitable layer thickness.

Next, the power generation system of the present invention will be described.

The power generation system of the present invention comprises: the photovoltaic element of the present invention; and the electrode from the photovoltaic element to a storage battery and / or an external load for monitoring voltage and / or current of the photovoltaic element. It is composed of a control system for controlling supply, and a storage battery for storing power from the photovoltaic element and / or supplying power to an external load.

FIG. 19 shows an example of the power supply system of the present invention, which is a basic circuit for charging and power supply using a photovoltaic element. In this circuit, the photovoltaic element of the present invention is used as a solar cell module and a backflow prevention diode (D
C), a voltage control circuit (constant voltage circuit) that monitors the voltage and controls the voltage, a storage battery, a load, and the like.

In order to form a module, an adhesive sheet and a nylon sheet are placed on a flat plate, the photovoltaic elements of the present invention are further arranged on the flat sheet, serialized and parallelized, and further adhered on it. It is advisable to place an agent sheet or a fluororesin sheet on the sheet and perform vacuum lamination.

A silicon diode, a Schottky diode, or the like is suitable as the backflow prevention diode. Examples of the storage battery include a nickel cadmium battery, a rechargeable silver oxide battery, a lead storage battery and a flywheel energy storage unit.

The voltage control circuit is almost equal to the output of the solar battery until the battery is fully charged, but when the battery is fully charged, the charging current is stopped by the charging control IC.

The solar cell system using such a photovoltaic element can be used as a power source for a battery charging system for automobiles, a battery charging system for ships, a streetlight lighting system, an exhaust system and the like.

As described above, the power supply system using the photovoltaic element of the present invention as a solar cell can be used stably for a long period of time, and the photovoltaic power can be applied even when the irradiation light applied to the solar cell fluctuates. Since it functions sufficiently as an element, it exhibits excellent stability.

[0247]

EXAMPLES The photovoltaic element of the present invention will be described in detail below by making a solar cell and a photodiode made of a non-single crystal silicon semiconductor material, but the present invention is not limited to this.

[Embodiment of Claim 1] (Embodiment 1) Using the deposition apparatus shown in FIG. 11, FIG.
A solar cell having the above structure was produced. RFPCV for n-type layer
It was formed by the D method.

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. Using a sputtering method at room temperature, a light-reflecting layer of Ag having a layer thickness of 0.3 μm and a reflection-increasing layer of ZnO having a layer thickness of 1.0 μm at 350 ° C. are formed on the surface of the light-reflecting layer and the fabrication of the substrate ends It was

Next, the deposition apparatus 400 can carry out both the MWPCVD method and the RFPCVD method, and can carry out the sputtering of alkali metal at the same time. Using this, each semiconductor layer was formed on the reflection increasing layer.

A raw material 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 cylinder, SiF ₄ gas cylinder, CH ₄ gas cylinder, GeH
₄ gas cylinder, GeF ₄ gas cylinder, SnH ₄ gas cylinder, PH ₃ / H ₂ (dilution degree: 100 ppm) gas cylinder, B ₂ H ₆ / H ₂ (dilution degree: 100 ppm) gas cylinder, H ₂ gas cylinder, He gas cylinder, O ₂ / He Gas cylinder, N ₂ / He gas, LiH ₂ heated to 120 ° C.
A liquid cylinder of PO ₄ was connected. A He gas cylinder different from the He gas cylinder is connected to the liquid cylinder, and He gas can be bubbled. LiF was used as the target, it was attached to the target electrode, and the RF power source was used as the target power source.

Next, the back surface of the substrate 404 on which the reflection layer and the reflection increasing layer are formed is brought into close contact with the heater 405, the leak valve 409 in the deposition chamber 401 is closed, the conductance valve 407 is fully opened, and a vacuum (not shown) is provided. The inside of the deposition chamber 401 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 RFn type layer made of μc-Si is formed on the substrate 404.
An i-type layer made of a-Si, an RFp-type layer made of a-SiC, and a MWp-type layer made of a-SiC were sequentially formed.

To form the RFn-type layer made of μc-Si, H ₂ gas was introduced into the deposition chamber 401, and the flow rate was 30.
The mass flow controller adjusted the pressure to 0 sccm, and the conductance valve adjusted the pressure in the deposition chamber to 1.0 Torr. Substrate 404 temperature is 3
The heater 405 was set to 50 ° C., and when the substrate temperature became stable, SiH ₄ gas and PH ₃ / H ₂ gas were caused to flow into the deposition chamber 401. At this time, the SiH ₄ gas flow rate is ₂ sccm, the H ₂ gas flow rate is 100 sccm, and P
The H ₃ / H ₂ gas flow rate was adjusted to 200 sccm, and the pressure inside the deposition chamber was adjusted to 1.0 Torr. The power of the RF power source was set to 0.02 W / cm ³ , and the bias electrode 410
RF power is introduced to cause a glow discharge, the shutter is opened, the formation of the RF n-type layer is started on the substrate, and the layer thickness is 2
When the 0 nm RFn-type layer was formed, the shutter was closed, the RF power supply was turned off, the glow discharge was stopped, and the formation of the RFn-type layer was completed. SiH ₄ gas in the deposition chamber, PH ₃ /
Stopping the flow of H _2, 5 minutes, after which continued to flow H ₂ gas into the deposition chamber, the flow of H ₂ is also stopped, and vacuum evacuating the deposition chamber and the gas in the pipe up to 1 × 10 ^-5 Torr.

The i-type layer made of a-Si was formed by simultaneously performing the MWPCVD method and the alkali metal sputtering. First, 300 sccm of H ₂ gas was introduced, the pressure was 0.01 Torr, and the temperature of the substrate 404 was 35.
It was adjusted to 0 ° C. When the substrate temperature is stable,
SiH ₄ gas and He gas are introduced, the SiH ₄ gas flow rate is 150 sccm, the He gas flow rate is 150 sccm, H
_{2 The} gas flow rate was 150 sccm, and the pressure inside the deposition chamber 401 was adjusted to 0.01 Torr. Then R
The power of the F power source was set to 0.35 W / cm ³ and applied to the bias electrode. Then, the power of an MW power source (not shown) was set to 0.20 W / cm ³ , and the MW power was introduced into the deposition chamber through the dielectric window 413 to cause glow discharge. Next, the power of the target power source was set to 200 W, the target shutter 417 was opened, the shutter 415 was opened, and formation of the i-type layer on the RF n-type layer was started. Using a computer connected to the RF power source and the target power source, the RF power and the target power were changed according to the change pattern shown in FIG. 12A to form the i-type layer having a layer thickness of 300 nm. After closing, the MW power supply, the RF power supply and the target power supply were turned off to stop the glow discharge, and the formation of the i-type layer was completed. SiH
The inflow of ₄ gas and He gas was stopped, and H ₂ gas was continued to flow for 5 minutes, and then the inflow of H ₂ gas was stopped, and the deposition chamber and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr.

An RF p-type layer made of a-SiC is formed.
To H₂Gas is introduced at 300 sccm and the pressure is 1.0
Torr and the substrate temperature were set to 200 ° C. substrate
When the temperature stabilizes, SiH_FourGas, CH_Fourgas,
B₂H₆/ H₂Gas is allowed to flow into the deposition chamber and SiH_FourMoth
Flow rate is 5 sccm, CH_FourGas flow rate is 1 sccm, H
₂Gas flow rate is 100 sccm, B₂H₆/ H₂Gas flow
So that the pressure is 200 sccm and the pressure is 1.0 Torr
It was adjusted. RF power 0.06W / cm ³Set to
Then, a glow discharge is generated, the shutter is opened, and the i-type layer
The formation of the RFp type layer is started on the upper side and the
When the mold layer is formed, close the shutter and turn on the RF power source.
Turn off, stop glow discharge, and finish forming RF p-type layer
It was SiH in the deposition chamber_FourGas, CH_FourGas, B₂H₆
/ H₂Stop gas inflow for 5 minutes, H₂Keep flowing gas
After that, H₂Also stop the inflow of gas and settle
1 x 10 in the pipe^-FiveEvacuated to Torr.

To form the MWp type layer made of a-SiC, H ₂ gas was introduced at 500 sccm, the pressure inside the deposition chamber was set to 0.02 Torr, and the substrate temperature was set to 200 ° C.

When the substrate temperature became stable, SiH ₄ gas, CH ₄ gas, and B ₂ H ₆ / H ₂ gas were introduced. At this time, SiH ₄ gas flow rate is 10 sccm, CH ₄ gas flow rate is ₂ sccm, H ₂ gas flow rate is 100 sccm, and B ₂
H ₆ / H ₂ gas flow rate is 500seem, pressure is 0.02
It was adjusted to be Torr. After that, MW not shown
The power of the power supply was set to 0.40 W / cm ³ , MW power was introduced through the dielectric window to cause glow discharge, the shutter was opened, and formation of the MWp type layer on the RFp type layer was started. When a WMp type layer having a layer thickness of 10 nm is formed,
The shutter was closed, the MW power was turned off to stop the glow discharge, and the formation of the MWp type layer was completed. SiH ₄ gas, CH ₄
Gas, B ₂ H ₆ / H ₂ gas flow is stopped, H ₂
After continuing to flow the gas, the inflow of H ₂ gas was stopped, the deposition chamber and the gas pipe were evacuated to 1 × 10 ⁻⁵ Torr, the auxiliary valve 408 was closed, the leak valve 409 was opened, and the deposition chamber was leaked. .

Next, as a transparent electrode on the MWp type layer,
ITO having a layer thickness of 70 nm was vacuum deposited by a vacuum deposition method.

Next, a mask having comb-shaped holes is placed on the transparent electrode, and Cr (40 nm) / Ag (1000 nm) / C
A comb-shaped collector electrode made of r (40 nm) was vacuum-deposited by a vacuum deposition method.

The fabrication of the solar cell was completed as described above. This solar cell will be called (SC Ex 1), and Table 1 shows the conditions for forming the RFn-type layer, the i-type layer, the RFp-type layer, and the MWp-type layer.

Comparative Example 1-1 When forming the i-type layer,
A solar cell (SC) was used under the same conditions as in Example 1 except that the RF power was constant over time and the target power was also constant over time.
Ratio 1-1) was produced. Comparative Example 1-2 A solar cell (SC ratio 1-2) was produced under the same conditions as in Example 1 except that the RFp type layer was not formed and the layer thickness of the MWp type layer was 20 nm.

Solar cells (SC Ex 1) and (SC ratio 1-
1) and 6 (SC ratio 1-2) were produced, and the initial photoelectric conversion efficiency (photovoltaic power / incident light power), vibration deterioration,
Photodegradation, and vibration and photodegradation were measured in a high temperature and high humidity environment when a bias voltage was applied.

The initial photoelectric conversion efficiency can be measured by placing the manufactured solar cell under AM-1.5 (100 mW / cm ² ) light irradiation and measuring the VI characteristic. As a result of the measurement, for (SC Ex 1), (SC Ratio 1-
The initial photoelectric conversion efficiencies of 1) and (SC ratio 1-2) are as follows.

(SC ratio 1-1) 0.96 times (SC ratio 1-2) 0.95 times The vibration deterioration was measured by measuring the solar cell whose initial photoelectric conversion efficiency was measured in advance at a humidity of 50% and a temperature. Install in a dark place at 25 ° C, and vibrate with an oscillation frequency of 60 Hz and an amplitude of 0.1 mm.
AM1.5 (100 mW / cm ² ) after adding for 0 hours
It was determined by the rate of decrease in photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after vibration deterioration test / initial photoelectric conversion efficiency).

Photodegradation was measured by placing a solar cell whose initial photoelectric conversion efficiency had been measured in advance in an environment of a humidity of 50% and a temperature of 25 ° C. and applying AM-1.5 (100 mW / cm ² ) light. AM-1.5 (100 mW / c after irradiation for 500 hours
m ² ) The decrease rate of photoelectric conversion efficiency under irradiation (photoelectric conversion efficiency after photodegradation test / initial photoelectric conversion efficiency) was used.
As a result of the measurement, (SC Ex 1) (SC Ratio 1-1),
(SC ratio 1-2), the rate of decrease in photoelectric conversion efficiency after photodegradation,
The rate of decrease in photoelectric conversion efficiency after vibration deterioration was as follows.

Vibration deterioration Light deterioration (SC ratio 1-1) 0.94 times 0.92 times (SC ratio 1-2) 0.95 times 0.93 times Next, vibration in a high temperature and high humidity environment when a bias is applied. The deterioration and the light deterioration were measured. Two solar cells whose initial photoelectric conversion efficiency was measured in advance were installed in a dark place with a humidity of 90% and a temperature of 80 ° C., and a forward bias voltage of 0.
8V was applied. The above vibration was applied to one solar cell to measure vibration deterioration, and the other solar cell was irradiated with light of AM1.5 to measure light deterioration. As a result of the measurement, (SC ex 1), (SC ratio 1-1),
The decrease rate of the photoelectric conversion efficiency after vibration deterioration of (SC ratio 1-2) and the decrease rate of the photoelectric conversion efficiency after light deterioration were as follows.

Vibration deterioration Photodegradation (SC ratio 1-1) 0.95 times 0.94 times (SC ratio 1-2) 0.93 times 0.93 times The state of layer delamination was observed using an optical microscope. Delamination was not observed in (SC Ex 1) and (SC ratio 1-1), but slight delamination was observed in (SC ratio 1-2).

Next, using a glass substrate and a silicon wafer,
An i-type layer sample was prepared under the same conditions as in Example 1 except that the RF power and the target power were constant over time and the layer thickness was 1 μm. Furthermore, several samples were prepared with various RF power and target power. The band gap (Eg) of the glass substrate sample produced using the spectrophotometer was determined, and the secondary ion mass spectrometer (S
The hydrogen content of the silicon wafer sample was measured using IMS). As a result of the measurement, it was found that the band gap in the i-type layer depends on the hydrogen content.

Further, the change in the hydrogen content and the change in the alkali metal content in the layer thickness direction of the manufactured (SC Ex 1) were obtained by using SIMS, and the result was as shown in FIG. 12 (b).

Further, when the change of the band gap in the layer thickness direction was obtained by using the relationship between the hydrogen content and the band gap, it was as shown in FIG. 12 (c).

Similarly, when the hydrogen content and the alkali metal content (SC ratio 1-1) were determined, the hydrogen content did not change in the layer thickness direction and was constant, and the band gap was 1.
It was found to be 73 (eV). Similarly (SC ratio 1
When the hydrogen content and the alkali metal content of -2) were obtained, the change in the hydrogen content in the layer thickness direction was as shown in FIG.
The result is similar to that of Fig. 12 and the band gap changes.
The result was similar to that of (c).

Thus, the hydrogen content in the layer thickness direction,
It was found that the change of the band gap and the band gap depended on the introduced RF power, and the change of the alkali metal content in the layer thickness direction depended on the introduced target power.

Also, vibration deterioration and light deterioration in a high temperature environment, and vibration deterioration and light deterioration in a high humidity environment were measured. Similarly, (SC Ex 1) was (SC ratio 1-1),
It had characteristics superior to those of Comparative 1-2).

Further, when a forward bias is applied in the above environment, (SC Ex 1) becomes (SC Comp Ex 1-1) similarly,
(SC ratio 1-2) had better characteristics.

As described above, the solar cell of this embodiment (SC Ex 1) is the same as the conventional solar cell (SC Comp Ex 1-1), (SC Comp Ex 1).
It was found that it has more excellent characteristics than that of -2).

Example 2 When the i-type layer was formed in Example 1, the alkali metal content and hydrogen content were changed as shown in FIG. 3B by changing the change patterns of RF power and target power.
A solar cell (SC Ex 2) that changed as described above was produced. Therefore, when the same measurement as in Example 1 was performed, (S
It has been found that the solar cell of C Ex 2) has characteristics further superior to those of the conventional solar cells (SC ratio 1-1) and (SC ratio 1-2), as in Example 1.

Example 3 A photodiode (PD Ex 3) having the layer structure shown in FIG. 1C was manufactured.

First, a substrate was manufactured. 0.5m thickness
m, 20 × 20 mm ² glass substrate was ultrasonically washed with acetone and isopropanol, dried with warm air, and a light-reflecting layer of Al having a layer thickness of 0.1 μm was formed on the glass substrate surface at room temperature by vacuum deposition. The fabrication of the substrate was completed.

In the same manner as in Example 1, the MWn type layer (a-SiC), RFn type layer (a-SiC), i type layer (a-Si), and RFp type layer (a-SiC) were formed on the substrate. It was formed sequentially. Further, when the i-type layer is formed, the RF power and the target power are temporally changed to change the alkali metal content and the hydrogen content as shown in FIG. 3C. Was produced. Table 2 shows the layer forming conditions of the semiconductor layer.

Next, a transparent electrode and a collector electrode were formed on the RF p-type layer in the same manner as in Example 1.

(Comparative Example 3-1) When forming the i-type layer, the photodiode (under the same conditions as in Example 3 except that the RF power and the target power were not temporally changed as in Comparative Example 1-1). A PD ratio 3-1) was produced.

(Comparative Example 3-2) No RFn type layer was formed,
A photodiode (PD ratio 3-2) was produced under the same conditions as in Example 3 except that the layer thickness of the MWn type layer was 40 nm.

The ON / OFF ratio (photocurrent / dark current measurement frequency of 10 kHz when irradiated with AM1.5 light) of the manufactured photodiode was measured. This is called an initial on / off ratio. Next, the same measurement as in Example 1 was performed for the on / off ratio. As a result, the photodiode (PD Ex 3) of this embodiment is the same as the conventional photodiode (PD PD 3).
It was found that the characteristics are more excellent than those of the ratios 3-1) and (PD ratio 3-2).

Example 4 A solar cell of FIG. 1B having a nip type structure was manufactured by reversing the stacking order of the n type layer and the p type layer. As in Example 1, the RF p-type layer (μ
c-Si), i-type layer (a-Si), RFn-type layer (a-S)
iC) and a MWn type layer (a-SiC) were formed.

When the i-type layer is formed, the RF power and the target power are changed with time to change the alkali metal content and the hydrogen content as shown in FIG. 3C. 4) was produced. The conditions for forming the semiconductor layer are shown in Table 3. The layers other than the semiconductor layer and the substrate were manufactured under the same conditions as in Example 1.

Comparative Example 4-1 When forming the i-type layer,
A solar cell (SC ratio 4-1) was produced under the same conditions as in Example 4, except that the RF power and the target power were not changed with time as in Comparative Example 1-1.

(Comparative Example 4-2) No RFn type layer was formed,
A solar cell (SC ratio 4-2) was produced under the same conditions as in Example 4 except that the layer thickness of the MWn type layer was 20 nm.

When the same measurement as in Example 1 was carried out, the solar cell of this example (SC Ex 4) was found to be the same as the conventional solar cell (SC Ex.
It was found that the characteristics were more excellent than those of the ratio 4-1) and (SC ratio 4-2).

(Example 5) i-type layer, MWp-type layer, RFp
The mold layer was made to contain fluorine, and a solar cell having a minimum fluorine content near the interface was produced. When forming the i-type layer, the MWp-type layer, and the RFp-type layer, SiF ₄ is newly introduced, and the SiF ₄ gas flow rate is changed with time.
A variation pattern of the fluorine content as shown in (a) was obtained. Other than this, it produced on the same conditions as Example 1. When the same measurement as in Example 1 was performed, the solar cell (SC Ex. 5) showed (S
It was found that it had even better characteristics than C Ex 1). No delamination was observed.

Example 6 A solar cell having a maximum hydrogen content near the interface of the MWp type layer and near the interface of the RFp type layer was produced. Figure 3 by changing the MW power with time
A change pattern of hydrogen content as shown in (c) was obtained. Other than this, it produced on the same conditions as Example 1. When the same measurement as in Example 1 was performed, the solar cell (SC Ex 6) showed (SC
It was found that it has even better characteristics than Ex 1).

Example 7 A solar cell in which the content of the valence electron control agent was maximum near the interface between the MWp type layer and the RFp type layer was produced. The source gas of the valence electron control agent to be introduced was changed with time to change the content of B atom as shown in FIG. 13 (b). (A secondary ion mass spectrometer was used for this measurement.) Other than this, the sample was manufactured under the same conditions as in Example 6.
When the same measurement as in Example 1 was performed, the solar cell (S
It was found that C Ex. 7) had better properties than (SC Ex. 6).

Example 8 A solar cell having the structure shown in FIG. 1A was produced. As in Example 1, the MWn type layer (μc-Si), the RFn type layer (a-Si), the i type layer (a-Si), the RFp type layer (a-SiC), and the MWp type layer (μc) were formed on the substrate. -SiC) were sequentially laminated. The same material as in Example 1 was used except for the semiconductor layer. When the same measurement as in Example 1 was performed, it was found that the solar cell (SC Ex 8) had further excellent characteristics than (SC Ex 1).

(Example 9) Using a-SiC for the i-type layer,
A solar cell containing an alkali metal was produced by using the MWPCVD method. First, the target, target electrode, and target shutter shown in FIG. 11 were removed from the deposition chamber. When forming the i-type layer, LiH ₂ PO ₄ / He gas newly bubbled with CH ₄ gas and He gas was used.
CH ₄ gas flow rate was 20 sccm, and LiH ₂ PO ₄ /
The He gas flow rate was changed with time so that the alkali metal content was as shown in FIG. A solar cell (SC Ex 9) was manufactured under the same conditions as in Example 1 except for the above.

(Comparative Example 9-1) When forming the i-type layer, L
A solar cell (SC ratio 9-1) was produced under the same conditions as in Example 9 except that the iH ₂ PO ₄ / He gas flow rate was constant over time.

(Comparative Example 9-2) No RF p-type layer was formed,
A solar cell (SC ratio 9-2) was produced under the same conditions as in Example 9 except that the layer thickness of the MWp type layer was 20 nm.

When the same measurement as in Example 1 was carried out, the solar cell of this example (SC Ex 9) showed that the conventional solar cell (S
It was found that the characteristics were more excellent than those of C ratio 9-1) and (SC ratio 9-2).

Example 10 A solar cell was prepared in which a-SiGe was used for the i-type layer and lithium, sodium, and potassium were contained as alkali metals. First, the target was exchanged with a mixture of LiF, NaF, and KF in a ratio of 10: 5: 1.
A solar cell (SC Ex 10) was produced under the same conditions as in Example 1 except that eF ₄ gas was used, a GeF ₄ gas flow rate was introduced at 30 sccm, and the layer thickness was set to 250 nm.

(Comparative Example 10-1) When forming an i-type layer,
A solar cell (SC ratio 10-1) was produced under the same conditions as in Example 10 except that the RF power and the target power were temporally constant as in Comparative Example 1-1.

(Comparative Example 10-2) Example 1 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 10-2) was produced under the same conditions as 0.

When the same measurement as in Example 1 was carried out,
It was found that the solar cell (SC Ex 10) of the present example had better characteristics than the conventional solar cells (SC ratio 10-1) and (SC ratio 10-2).

Example 11 A solar cell was prepared in which a-SiSn was used for the i-type layer and cesium was contained as an alkali metal. First, replace the target with CsNO ₃ and
When the mold layer is formed, SnH ₄ gas is newly introduced to
A solar cell (SC Ex 11) was produced under the same conditions as in Example 1 except that the H ₄ gas flow rate was 20 sccm.

(Comparative Example 11-1) When the i-type layer was formed, the solar power was adjusted under the same conditions as in Example 11 except that the RF power and the target power were temporally constant as in Comparative Example 1-1. A battery (SC ratio 11-1) was produced.

Comparative Example 11-2 Example 1 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 11-2) was produced under the same conditions as in 1.

When the same measurement as in Example 1 was carried out, the solar cell of this example (SC Ex 11) was further improved than the conventional solar cells (SC ratio 11-1) and (SC ratio 11-2). It has been found to have excellent properties.

Example 12 Between the RF p-type layer and the i-type layer,
And a PR-i layer between the RF n-type layer and the i-type layer.
The solar cell of (c) was produced. For the other layers, a solar cell was produced in the same manner as in Example 8. The two RF-i layers are made of a-Si, the SiH ₄ gas flow rate is 2 sccm, H
₂ Gas flow rate is 50 sccm, pressure in deposition chamber is 1.0T
Orr, the RF power to be introduced was 0.01 W / cm ³ , the substrate temperature was 270 ° C., and the layer thickness was 20 nm. When the same measurement as in Example 1 was performed, it was found that the solar cell (SC Ex 12) had further excellent characteristics than (SC Ex 8).

Example 13 A triple type solar cell shown in FIG. 14 was produced using the deposition apparatus of FIG. 11 using the MWPCVD method.

First, a substrate was manufactured. As in Example 1, a 50 × 50 mm ² stainless steel substrate was ultrasonically cleaned with acetone and isopropanol and dried. A layer thickness of 0.3 is formed on the surface of the stainless steel substrate by using the sputtering method.
A light reflection layer of Ag of Ag was formed. At this time, the substrate temperature is set to 350 ° C., and the substrate surface is uneven (textured).
I chose A ZnO reflection increasing layer having a layer thickness of 2.0 μm was formed thereon at a substrate temperature of 350 ° C.

Then, the preparation for film formation was completed by the same method as in Example 1. In the same manner as in Example 1, the first MWn was formed on the substrate.
A first RFn type layer (a-Si), a first i-type layer (a-SiGe), and a first RFp type layer (a-Si layer thickness 10 nm). , The first MWp
Type layer (μc-Si layer thickness 10 nm), second RFn type layer (μc-Si), second i-type layer (a-Si), second R
Fp type layer (a-SiC layer thickness 10 nm), second MWp type layer (μc-SiC layer thickness 10 nm), third RFn type layer (a-SiC), third i type layer (a-SiC) , Third RF p-type layer (a-SiC layer thickness 10 nm), third MW
A p-type layer (μc-SiC layer thickness 10 nm) was sequentially formed. When forming each semiconductor layer, SiF ₄ gas is introduced,
By changing the SiH ₄ gas flow rate and the SiF ₄ gas flow rate with time, the change in the hydrogen content of each layer in the layer thickness direction is shown in FIG.
I did like (c). Further, the target electric power was changed with time to change the alkali metal content as shown in FIG. 3 (c).

Next, a transparent electrode and a current collecting electrode similar to those in Example 1 were formed on the third MWp type layer.

With the above, the triple type solar cell (SC Ex 13)
Has been completed.

(Comparative Example 13-1) A solar cell (SC ratio 13-1) was produced under the same conditions as in Example 13, except that the target power was constant over time when each semiconductor layer was formed.

(Comparative Example 13-2) The first RFp type layer, the second RFp type layer, and the third RFp type layer were not formed, but the first MWp type layer and the second MWp type layer were formed. A solar cell (SC ratio 13-2) was produced under the same conditions as in Example 13, except that the layer thickness and the layer thickness of the third MWp type layer were 20 nm.

When the same measurement as in Example 1 was carried out, the solar cell of this example (SC Ex 13) was further improved than the conventional solar cells (SC ratio 13-1) and (SC ratio 13-2). It has been found to have excellent properties.

Example 14 A tandem solar cell shown in FIG. 15 was produced using the deposition apparatus using the roll-to-roll method shown in FIG.

First, as the substrate, a long stainless sheet having a length of 300 m, a width of 30 cm and a thickness of 0.1 mm, both surfaces of which were mirror-polished, was used. A substrate temperature of 3 on the surface of the stainless steel substrate was measured by a sputtering device using a roll-to-roll method.
A light-reflecting layer made of Ag having a layer thickness of 0.3 μm is continuously formed at 50 ° C., and Z having a layer thickness of 2.0 μm is further formed at a substrate temperature of 350 ° C.
A reflection-increasing layer made of nO was continuously formed. It was found that the substrate surface was textured as in Example 13.

FIG. 20 is a schematic view of a continuous semiconductor layer forming apparatus using the roll-to-roll method.

In this apparatus, a substrate delivery chamber 910, a plurality of deposition chambers 901 to 909, and a substrate winding chamber 911 are sequentially arranged, and they are connected by a separation passage 912 to form a long substrate 913. Can be continuously moved from the substrate feeding chamber to the substrate winding chamber through them, and simultaneously with the movement of the substrate, respective semiconductor layers can be simultaneously formed in the respective deposition chambers.

FIG. 21B is a view of the deposition chamber viewed from above.
Each deposition chamber has a source gas inlet 914 and a source gas exhaust port 915, an RF electrode 916 or a microwave applicator 917 is attached as necessary, and a halogen lamp heater 91 for heating the substrate is further provided.
8 is installed inside. In addition, the source gas inlet 91
4 is connected to the same source gas supply device as in Example 1, and each deposition chamber has a source gas exhaust port,
A vacuum exhaust pump such as an oil diffusion pump or a mechanical booster pump is connected to each exhaust port. An RF power source is connected to each RF electrode, and a MW power source is connected to the microwave applicator.

Deposition chambers 903 and 90 which are i-type layer deposition chambers
7, a bias electrode 931 and a target electrode 930 are arranged, and an RF power source is connected to each as a power source. Furthermore, NaF was used as a target.

FIG. 21A is a side view of the deposition chamber for the i-type layer. By arranging a target having a surface area smaller than the substrate area in the deposition chamber substantially in the center of the deposition chamber, The amount of alkali metal sputtered on the substrate central portion 942 is larger than that of the substrate peripheral portion 941. By doing so, the change in the thickness direction of the alkali metal-containing layer becomes as shown in FIG.

The separation passage connected to the deposition chamber has an inlet 919 through which scavenging gas flows. In the substrate delivery chamber, there are a delivery roll 920 and a guide roll 921 for applying an appropriate tension to the substrate and keeping it always horizontal. In the substrate winding chamber, a winding roll 922 and a guide roll 923.
There is.

First, the substrate on which the light reflection layer and the reflection increasing layer are formed 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 wrapped around a substrate winding roll. The entire apparatus is evacuated by a vacuum exhaust pump (not shown), the lamp heater in each deposition chamber is turned on, and the substrate temperature in each deposition chamber is set to a predetermined temperature. When the pressure of the entire apparatus becomes 1 mTorr or less, He gas is introduced from the inlet 919 of the scavenging gas, and the substrate is taken up by the take-up roll while moving in the direction of the arrow in the figure. In the same manner as in Example 1, each source gas is caused to flow into each deposition chamber. At this time, the flow rate of the H ₂ gas flowing into each separation passage or the pressure of each deposition chamber is adjusted so that the source gas flowing into each deposition chamber does not diffuse to the other deposition chambers.

Next, RF power or MW power is introduced to cause glow discharge to form the respective semiconductor layers.

A first MWn-type layer (μc-Si layer thickness 20 nm) is formed on the substrate in the deposition chamber 901, and a first RFn-type layer (a-Si layer thickness 10 n) is further formed in the deposition chamber 902.
m), the first i-type layer (a-SiGe layer thickness 180 nm) in the deposition chamber 903, and the first RFp-type layer (a) in the deposition chamber 904.
-Si layer thickness 10 nm), first MWp in deposition chamber 905
Type layer (μc-Si layer thickness 10 nm), the second RFn type layer (μc-Si layer thickness 20 nm) in the deposition chamber 906, the second i-type layer (a-Si layer thickness 250 nm) in the deposition chamber 907,
In the deposition chamber 908, the second RF p-type layer (a-SiC layer thickness 1
0 nm), the second MWp-type layer (μc-S) in the deposition chamber 909.
The iC layer thickness of 10 nm) was sequentially formed.

The raw material gas inlets of the deposition chambers 903 and 907 for forming the first i-type layer and the second i-type layer are divided into a plurality of portions, and the raw material gas was introduced from each of the inlets. First
When forming the i-type layer, arrows change pattern for the transport direction of the substrate of the SiF ₄ gas flow rate of Fig. 21 (b) 960
Thus, the change in the hydrogen content of the i-type layer in the layer thickness direction was set as shown in FIG. 3C, and the change in the fluorine content in the layer thickness direction was set as shown in FIG. 10C. When the transfer of the substrate was completed, all MW power supplies, RF power supplies, and target power supplies were turned off, glow discharge was stopped, and inflow of raw material gas and scavenging gas was stopped. The whole device was leaked and the wound substrate was taken out.

Next, a transparent electrode made of ITO having a layer thickness of 70 nm was continuously formed at 170 ° C. on the second MWp type layer by a sputtering device using a roll-to-roll method.

Next, a part of this substrate is set to 50 mm × 50 mm.
The size is cut, and a carbon paste having a layer thickness of 5 μm and a line width of 0.5 mm is printed by a screen printing method, and a silver paste having a layer thickness of 10 μm and a line width of 0.5 mm is printed on the carbon paste to form a collector electrode. Formed.

Thus, the production of the tandem solar cell (SC Ex 14) using the roll-to-roll method is completed.

(Comparative Example 14-1) When forming the first i-type layer and the second i-type layer, a target having a large surface area was used and the alkali metal content was uniform in the layer thickness direction. A solar cell (SC ratio 14-1) was produced under the same conditions as in Example 14 except for the above.

(Comparative Example 14-2) Without forming the first RFp type layer and the second RFp type layer, the first MWp type layer,
A solar cell (SC ratio 14-2) was produced under the same conditions as in Example 14 except that the second MW p-type layer had a layer thickness of 20 nm.

When the same measurement as in Example 1 was carried out, the solar cell of this example (SC Ex 14) was further improved than the conventional solar cells (SC ratio 14-1) and (SC ratio 14-2). It has been found to have excellent properties.

Example 15 A tandem solar cell manufactured by using the deposition apparatus shown in FIG. 20 was modularized, applied to a power generation system, and subjected to a field test.

50 mm of non-irradiated light produced in Example 14
65 x 50 mm tandem solar cells (SC Ex 14)
I prepared one. EV on a 5.0 mm thick aluminum plate
Put an adhesive sheet made of A (ethylene vinyl acetate), put a nylon sheet on it, and put 65 sheets on it.
The solar cells were arranged and serialized and parallelized.
An EVA adhesive sheet was placed thereon, a fluororesin sheet was placed thereon, and vacuum lamination was performed to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured by the same method as in Example 1. An external light which was connected to the circuit of the power generation system shown in FIG. 19 and was turned on at night was used as a load. The entire system is operated by the storage battery and the power of the module. This power generation system (SBS 1
5).

(Comparative Example 15) 65 conventional tandem solar cells (SC ratio 14-1) and (SC ratio 14-2) which were not irradiated with light were modularized in the same manner as in Example 15, and the initial photoelectric conversion was performed. The efficiency was measured. This module was connected to the same power generation system as in Example 15. These power generation systems (SBS ratio 15-1), (SBS ratio 15-
2).

[0336] Each module was installed at an angle at which 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 power generation system (SBS Ex. 15) using the solar cell of the present invention is the same as the conventional power generation system (SB
It was found that the initial photoelectric conversion efficiency and field durability were even better than those of S ratio 15-1) and (SBS ratio 15-2).

Example 16 The following photovoltaic element having oxygen and nitrogen atoms in the semiconductor layer was produced.

Example 16-1 When forming an i-type layer,
O ₂ / He gas is 100 sccm, N ₂ / He gas is 2
A solar cell (SC Ex 16-1) was produced under the same conditions as in Example 1 except that 0 sccm was introduced.

(Example 16-2) When forming the RF-i layer, ₂ sccm of O ₂ / He gas and 1 of N ₂ / He gas were used.
A solar cell (SC Ex 16-2) was produced under the same conditions as in Example 1 except that sccm was introduced.

(Example 16-3) O ₂ / He gas of 100 sccm and N ₂ / He gas of 20 sccm were introduced at the time of forming the MWp type layer, and O _{2 at} the time of forming the RFp type layer.
/ He gas ₂ sccm, N ₂ / He gas 1 sccm
A solar cell (SC Ex 16-3) was produced under the same conditions as in Example 1 except that the solar cell was introduced.

When the same measurement as in Example 1 was carried out, the solar cells (SC Ex 16-1) to (SC Ex 16-3) had more excellent characteristics than the solar cell (SC Ex 1). I understood.

When the concentrations of oxygen atoms and nitrogen atoms of these fabricated solar cells were examined using SIMS, it was found that the concentrations of the introduced raw material gas (O) and the raw material gas (N) were almost the same as those of the introduced raw material gas (O). It was found to be contained.

Example of Claim 5 (Example 17) Using the deposition apparatus shown in FIG. 11, a solar cell having the structure shown in FIG. 1 (b) containing P and B atoms in the i-type layer was produced. . It was produced in the same manner as in Example 1 except for the i-type layer.

The i-type layer made of a-Si is shown below.
Sea urchin, MWPCVD method and alkali metal sputtering
Are formed simultaneously. First, H₂gas
Of 300 sccm and pressure of 0.01 Torr,
The temperature of the plate 404 was adjusted to 350 ° C. Substrate temperature
Is stable, SiH_FourGas, He gas, PH ₃
/ H₂Gas, B₂H₆/ H₂Inflow gas, SiH_Fourgas
Flow rate is 150 sccm, He gas flow rate is 150 sccc
m, H₂Gas flow rate is 150 sccm, PH₃/ H₂Gas flow
The amount is 2 sccm, B₂H₆/ H₂Gas flow rate is 2 sccm
However, the pressure in the deposition chamber 401 becomes 0.01 Torr.
I adjusted it. Next, the power of the RF power source is 0.32 W / c
m³And was applied to the bias electrode. Then unillustrated
The power of the indicated MW power source is 0.20 W / cm³Set to and invite
MW power is introduced into the deposition chamber through the electric window 413,
A low discharge was generated. Next, set the target power to 2
Set to 00W, open the target shutter 417,
Open the shutter and start forming the i-type layer on the RF n-type layer
did. After forming an i-type layer with a layer thickness of 300 nm,
Shutter, target shutter closed, MW power supply, R
Turn off the F power and target power to stop glow discharge and
The formation of the mold layer is completed.

This solar cell is called (SC Ex. 17), and Table 4 shows the conditions for forming the RFn-type layer, the i-type layer, the RFp-type layer, and the MWp-type layer.

(Comparative Example 17-1) A solar cell (SC ratio 17-1) was produced under the same conditions as in Example 17 except that PH ₃ / H ₂ gas was not introduced when forming the i-type layer. .

(Comparative Example 17-2) Example 17 was repeated except that B ₂ H ₆ / H ₂ gas was not introduced when forming the i-type layer.
A solar cell (SC ratio 17-2) was produced under the same conditions as described above.

(Comparative Example 17-3) Example 1 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 17-3) was produced under the same conditions as in No. 7.

Solar cell (SC Ex 17) and (SC ratio 17
-1) to (SC ratio 17-3) were produced in 6 pieces, respectively, and in the same manner as in Example 1, initial photoelectric conversion efficiency (photovoltaic power / incident optical power), vibration deterioration, light deterioration, and bias voltage application. We measured vibration deterioration and light deterioration in high temperature and high humidity environment.

As a result of the initial photoelectric conversion efficiency measurement, (SC Ex 1
7), (SC ratio 17-1) to (SC ratio 17-
The initial photoelectric conversion efficiency of 3) is as follows.

(SC ratio 17-1) 0.94 times (SC ratio 17-2) 0.93 times (SC ratio 17-3) 0.93 times Vibration deterioration and light deterioration measurement results (SC actual 17) On the other hand, the (SC ratio 17-1) to (SC ratio 17-3) showed the following reduction rates of the photoelectric conversion efficiency after the photodegradation and the photoelectric conversion efficiency after the vibration degradation.

Vibration deterioration Optical deterioration (SC ratio 17-1) 0.93 times 0.91 times (SC ratio 17-2) 0.93 times 0.90 times (SC ratio 17-3) 0.92 times 0. As a result of measurement of vibration deterioration and light deterioration in a high temperature and high humidity environment when a bias is applied 90 times, (S Ex 17),
The reduction ratio of the photoelectric conversion efficiency after vibration deterioration of the C ratio 17-1) to (SC ratio 17-3) and the reduction ratio of the photoelectric conversion efficiency after light deterioration were as follows.

Vibration deterioration Optical deterioration (SC ratio 17-1) 0.92 times 0.92 times (SC ratio 17-2) 0.91 times 0.91 times (SC ratio 17-3) 0.91 times 0. The state of delamination was observed using a 92 × optical microscope. In (SC Ex. 17), (SC ratio 17-1) and (SC ratio 17-2), no layer delamination was observed, but in (SC ratio 17-3) a slight layer delamination was observed.

Next, a secondary ion mass spectrometer (SIMS)
(SC Ex 17), (SC ratio 17-
The contents of P and B atoms of 1) to (SC ratio 17-3) were determined as follows.

──────────────────────────── P content B content ────────────── ─────────────── (SC Ex 17) 5ppm 10ppm (SC ratio 17-1) N. D. 10 ppm (SC ratio 17-2) 5 ppm N.V. D. (SC ratio 17-3) 5ppm 10ppm ──────────────────────────── In addition, vibration deterioration, light deterioration, and Vibration deterioration and light deterioration were measured in a high humidity environment. Similarly, (SC ex. 17) showed (SC ratio 17-1) to (SC ratio 17-
It had better properties than 3).

Further, even when a forward bias is applied in the above environment, (SC Ex 17) becomes (SC Comp Ex 17-1) similarly.
.About. (SC ratio 17-3).

As described above, the solar cell of this example (SC Ex 17) is the same as the conventional solar cells (SC ratio 17-1) to (SC).
It has been found that it has characteristics further superior to the ratio 17-3).

(Example 18) For the valence electron control agent in the i-type layer
The content changes smoothly in the layer thickness direction, and on the p-type layer side
A solar cell (SC Ex 18) having a large content was produced. PH
₃/ H₂Gas flow rate, B ₂H₆/ H₂Gas flow rate as shown in Figure 16
Under the same conditions as in Example 17, except that the solar cell was changed to
(SC Ex 18) was produced.

When the contents of P and B were obtained by SIMS in the same manner as in Example 17, it was found that the result was as shown in FIG. 5 (a). Moreover, when the same measurement as that of Example 17 was performed, it was found that (SC Ex. 18) exhibited even better characteristics than (SC Ex. 17).

Example 19 A photodiode (PD Ex 19) having the layer structure shown in FIG. 1C was manufactured.

First, a substrate was manufactured. 0.5m thickness
m, 20 × 20 mm ² glass substrate was ultrasonically washed with acetone and isopropanol, dried with warm air, and a light-reflecting layer of Al having a layer thickness of 0.1 μm was formed on the glass substrate surface at room temperature by vacuum deposition. The fabrication of the substrate was completed.

MWn was formed on the substrate in the same manner as in Example 17.
The type layer (a-SiC), the RFn type layer (a-SiC), the i-type layer (a-Si), and the RFp-type layer (μc-SiC) were sequentially formed. Table 5 shows the layer forming conditions of the semiconductor layer.

Then, a transparent electrode and a collector electrode were formed on the RF p-type layer in the same manner as in Example 17.

(Comparative Example 19-1) A photodiode (SC ratio 19-1) was produced under the same conditions as in Example 19 except that PH ₃ / H ₂ gas was not introduced when forming the i-type layer. .

(Comparative Example 19-2) Example 19 was repeated except that B ₂ H ₆ / H ₂ gas was not introduced when forming the i-type layer.
A photodiode (SC ratio 19-2) was manufactured under the same conditions as described above.

(Comparative Example 19-3) Example 1 was repeated except that the RFn type layer was not formed and the MWn type layer had a layer thickness of 40 nm.
Photodiode under the same conditions as 9 (PD ratio 19-3)
It was made.

The on / off ratio of the manufactured photodiode was measured. Next, the same measurement as in Example 17 was performed for the on / off ratio. As a result, the photodiode (PD actual 19) of this embodiment is the same as the conventional photodiode (PD ratio 1).
9-1) and (PD ratio 19-2) were found to have further excellent characteristics.

Example 20 A solar cell of FIG. 1 (b) having a nip type structure was manufactured by reversing the stacking order of the n type layer and the p type layer. As in Example 17, the RF p-type layer (μc-Si), the i-type layer (a-Si), and the RF n-type layer (a) were formed on the substrate.
-SiC) and a MWn type layer (a-SiC) were formed.

When forming the i-type layer, the target power was changed with time to change the alkali metal content in the layer thickness direction as shown in FIG. 5 (a). The conditions for forming the semiconductor layer are shown in Table 6. A solar cell (SC Ex 20) was produced under the same conditions as in Example 17, except for the layers other than the semiconductor layer and the substrate.

(Comparative Example 20-1) A solar cell (SC ratio 20-1) was produced under the same conditions as in Example 20 except that PH ₃ / H ₂ gas was not introduced when forming the i-type layer. .

(Comparative Example 20-2) Example 20 was repeated except that B ₂ H ₆ / H ₂ gas was not introduced when forming the i-type layer.
A solar cell (SC ratio 20-2) was produced under the same conditions as described above.

Comparative Example 20-3 Example 2 was repeated except that the RFn type layer was not formed and the MWn type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 20-3) was produced under the same conditions as 0.

(SC Ex 20-1) When forming the i-type layer,
A solar cell (SC Ex 20-1) was produced under the same conditions as in Example 20 except that the RF power was changed with time.

Next, using a glass substrate and a silicon wafer,
A constant RF power was applied, and an i-type layer having a thickness of 1 μm was formed on a glass substrate and a silicon wafer under the same conditions as in Example 17 to prepare samples for bandgap measurement and infrared absorption spectrum measurement, respectively. Furthermore, several samples with various RF powers were prepared. The band gap (Eg) of the glass substrate sample produced using a spectrophotometer was determined, and further the infrared absorption spectrum of the silicon wafer sample was measured to measure the hydrogen content. The relationship between the hydrogen content in the i-type layer and the band gap was obtained using the results of both.

Secondary ion mass spectrometer (SIMS)
When the hydrogen content in the layer thickness direction of (SC Ex. 20-1) produced by using was determined, it was found to be as shown in FIG. Further, when the changes in the hydrogen content and the band gap were obtained, it was found that the change was as shown in FIG.

Similarly (SC actual 20), (SC ratio 20-
When the hydrogen content of 1) to (SC ratio 20-3) was determined, it was found that there was no change in the hydrogen content in the layer thickness direction, it was constant, and the band gap was 1.73 (eV).

As described above, the hydrogen content in the layer thickness direction,
It was found that the change in bandgap and the bandgap depends on the RF power introduced.

When the same measurement as in Example 17 was carried out,
It was found that the solar cell (SC Ex 20) of this example has further excellent characteristics than the conventional solar cells (SC ratio 20-1) to (SC ratio 20-3). Also (SC real 20
It was found that -1) had even better characteristics than (SC Ex 20).

(Example 21) A solar cell was produced in which the fluorine content of the i-type layer was changed smoothly and the fluorine content was minimum near the interface with the RFp-type layer. When forming the i-type layer, the SiF ₄ gas flow rate was temporally changed to obtain a variation pattern of the fluorine content as shown in FIG. Except for this, it was manufactured under the same conditions as in Example 17. When the same measurement as in Example 17 was performed, it was found that the solar cell (SC Ex. 21) had better characteristics than (SC Ex. 17).

Example 22 A solar cell having the maximum hydrogen content near the interface between the MWp type layer and the RFp type layer was produced. By changing the RF power when forming the RFp layer,
A change pattern of hydrogen content as shown in FIG. 3B was obtained.
By changing the MW power with time, a change pattern of the hydrogen content as shown in FIG. 3C was obtained. Except for this, it was manufactured under the same conditions as in Example 17. When the same measurement as in Example 17 was carried out, it was found that the solar cell (SC Ex. 22) had further excellent characteristics than (SC Ex. 17).

(Example 23) A solar cell in which the content of the valence electron control agent was maximized in the vicinity of the interface between the MWp type layer and the RFp type layer was produced. When forming the MWp type layer and the RFp type layer, the source gas of the valence electron control agent introduced was changed with time to change the content of B atoms as shown in FIG. 13 (c). Except for this, it was manufactured under the same conditions as in Example 17. When the same measurement as in Example 17 was carried out, a solar cell (SC
It was found that Ex. 23) had even better characteristics than (SC Ex. 17).

(Example 24) A solar cell was prepared in which the MWp type layer and the RFp type layer contained fluorine, and the fluorine content was minimum near the interface. When forming the MWp type layer and the RFp type layer, SiF ₄ gas was newly introduced and the flow rate was changed with time to obtain a change pattern of the fluorine content as shown in FIG. Except for this, it was manufactured under the same conditions as in Example 17. When the same measurement as in Example 17 was performed, it was found that the solar cell (SC Ex. 24) had further excellent characteristics as compared to (SC Ex. 17).

Example 25 A solar cell having the structure shown in FIG. 1A was produced. As in Example 17, the MW was formed on the substrate.
The n-type layer (μc-Si), the RF n-type layer (a-Si), the i-type layer (a-Si), the RFp-type layer (a-SiC), and the MWp-type layer (μc-SiC) were sequentially stacked. When forming the i-type layer, the PH ₃ / H ₂ gas flow rate and the B ₂ H ₆ / H ₂ gas flow rate were changed with time so that the contents of B and P in the layer thickness direction were as shown in FIG.
So that The same material as in Example 17 was used except for the semiconductor layer. The solar cell (SC Ex 25) is (SC Ex 17)
It has been found to have even better properties.

(Example 26) Using a-SiGe for the i-type layer
Alkali metal was added using the MWPCVD method.
A solar cell was produced. First, the target and tar in Figure 11.
Get the electrode and target shutter from the deposition chamber
I removed it. When forming the i-type layer, a new GeH _FourGas and H
LiH bubbled with e-gas₂PO_Four/ Uses He gas
I was there. GeH _FourThe gas flow rate was 30 sccm, and LiH₂
PO_Four/ He gas flow rate is changed with time
The metal content is as shown in FIG. 3 (b), and the layer thickness of the i-type layer
Was 250 nm. Other conditions are the same as in Example 17.
A solar cell (SC Ex. 26) was produced in.

(Comparative Example 26-1) A solar cell (SC ratio 26-1) was produced under the same conditions as in Example 26, except that PH ₃ / H ₂ gas was not introduced when forming the i-type layer. .

(Comparative Example 26-2) Example 26 was repeated except that B ₂ H ₆ / H ₂ gas was not introduced when forming the i-type layer.
A solar cell (SC ratio 26-2) was produced under the same conditions as described above.

Comparative Example 26-3 Example 2 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 26-3) was manufactured under the same conditions as in No. 6.

When the same measurement as in Example 17 was carried out,
The solar cell (SC Ex 26) of the present embodiment is the solar cell (SC
It was found that the characteristics are more excellent than those of the ratios 26-1) to (SC ratio 26-3).

(Example 27) A solar cell was prepared in which a-SiSn was used for the i-type layer and lithium, sodium, and potassium were contained as alkali metals. First, the target was exchanged with a mixture of LiF, NaF, and KF at 10: 5: 1, and Al (CH 2
₃ ) ₃ (Trimethylaluminum TMA) A liquid cylinder is connected and He gas is bubbled with He gas.
The TMA / He gas diluted with was allowed to be introduced into the deposition chamber. When forming the i-type layer, the SiH ₄ gas flow rate was set to 1
10 sccm, SiF ₄ gas flow rate 20 sccm, Sn
H ₄ gas flow rate is 20 sccm, PH ₃ / H ₂ gas flow rate is 1
sccm, TMA / He gas was 10 sccm, the target power was changed with time, and the alkali metal content was changed as shown in FIG. It was made.

(Comparative Example 27-1) A solar cell (SC ratio 27-1) was produced under the same conditions as in Example 27, except that PH ₃ / H ₂ gas was not introduced when forming the i-type layer. .

(Comparative Example 27-2) Example 27 was repeated except that TMA / He gas was not introduced when forming the i-type layer.
A solar cell (SC ratio 27-2) was produced under the same conditions as described above.

(Comparative Example 27-3) Example 2 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 27-3) was produced under the same conditions as in No. 7.

When the same measurement as in Example 17 was carried out, the solar cell of this example (SC Ex 27) was further improved than the conventional solar cells (SC ratio 27-1) to (SC ratio 27-3). It has been found to have excellent properties.

Example 28 Between the RF p-type layer and the i-type layer,
And a PR-i layer between the RF n-type layer and the i-type layer.
The solar cell of (c) was produced. Example 25: other layers
A solar cell was produced in the same manner as in. The two RF-i layers are made of a-Si, and the SiH ₄ gas flow rate is 2 sccm,
PH ₃ / H ₂ gas gas flow rate 0.2 sccm, B ₂ H ₆ / H
₂ gas flow rate is 0.5 sccm, H ₂ gas flow rate is 50 sc
cm, pressure in the deposition chamber is 1.0 Torr, RF to be introduced
It was formed under the conditions of an electric power of 0.01 W / cm ³ , a substrate temperature of 270 ° C., and a layer thickness of 20 nm. When the same measurement as in Example 17 was performed, the solar cell (SC Ex 28) was
It has been found that it has even better properties than 5).

Example 29 A triple type solar cell shown in FIG. 14 was produced using the deposition apparatus of FIG. 11 using the MWPCVD method.

A substrate was manufactured in the same manner as in Example 13. Subsequently, a first MWn type layer (μc-Si) was formed on the substrate by the same method as in Example 17, and further the first RF was used.
n-type layer (a-Si), first i-type layer (a-SiGe),
First RF p-type layer (a-Si layer thickness 10 nm), first M
Wp type layer (μc-Si layer thickness 10 nm), second RFn
Type layer (μc-Si), second i-type layer (a-Si), second
RF p-type layer (a-SiC layer thickness 10 nm), second M
Wp type layer (μc-SiC layer thickness 10 nm), third RF
an n-type layer (a-SiC), a third i-type layer (a-SiC),
Third RF p-type layer (a-SiC layer thickness 10 nm), third
MWp type layer (μc-SiC layer thickness 10 nm) was sequentially formed. When forming the first i-type layer, the second i-type layer, and the third i-type layer, the flow rate was changed with time so that the P and B contents became as shown in FIG. 5 (a). . In other layers,
The MW power was changed with time in the layer formed by the MWPCVD method, and the RF power was changed in the layer formed by the RFPCVD method with time so that the distribution of the hydrogen content of each layer was as shown in FIG. 3C. In addition, the target electric power was changed with time during the formation of all semiconductor layers to show the change in the Li content.
(A). Next, a transparent electrode and a collector electrode similar to those in Example 17 were formed on the third MWp type layer.

[0398] Now the triple type solar cell (SC Ex 29).
Has been completed.

(Comparative Example 29-1) An example other than that PH ₃ / H ₂ gas was not introduced when forming the first i-type layer, the second i-type layer and the third i-type layer. A solar cell (SC ratio 29-1) was produced under the same conditions as 29.

(Comparative Example 29-2) In forming the first i-type layer, the second i-type layer and the third i-type layer, B ₂ H ₆ / H ₂
A solar cell (SC ratio 29-2) was produced under the same conditions as in Example 29 except that gas was not introduced.

(Comparative Example 29-3) The first RFp type layer, the second RFp type layer and the third RFp type layer were not formed, and the first RFp type layer was not formed.
A solar cell (SC ratio 29-3) was produced under the same conditions as in Example 29, except that the layer thicknesses of the MWp type layer, the second MWp type layer, and the third MWp type layer were each 20 nm.

When the same measurement as in Example 17 was carried out,
It was found that the solar cell (SC Ex 29) of the present example had better characteristics than the conventional solar cells (SC ratio 29-1) and (SC ratio 29-2).

Example 30 A tandem solar cell shown in FIG. 15 was manufactured using the deposition apparatus using the roll-to-roll method shown in FIG.

In the same manner as in Example 14, a light reflecting layer and a reflection increasing layer were continuously formed on a long stainless steel sheet.

A first MWn-type layer (μc-Si layer thickness 20 nm) is formed on the substrate in the deposition chamber 901, and a first RFn-type layer (a-Si layer thickness 10 n) is further formed in the deposition chamber 902.
m), the first i-type layer (a-SiGe layer thickness 180 nm) in the deposition chamber 903, and the first RFp-type layer (a) in the deposition chamber 904.
-Si layer thickness 10 nm), first MWp in deposition chamber 905
Type layer (μc-Si layer thickness 10 nm), the second RFn type layer (μc-Si layer thickness 20 nm) in the deposition chamber 906, the second i-type layer (a-Si layer thickness 250 nm) in the deposition chamber 907,
In the deposition chamber 908, the second RF p-type layer (a-SiC layer thickness 1
0 nm), the second MWp-type layer (μc-S) in the deposition chamber 909.
The iC layer thickness of 10 nm) was sequentially formed.

In this embodiment, when the first i-type layer and the second i-type layer are formed, as shown in FIG. 21, PH ₃ / H ₂ gas,
B ₂ H ₆ / H ₂ gas was separately introduced from the inlets 924 and 925 so that a large amount of valence electron control agent could be introduced near the interface of the i-type layer. Further, since a large amount of H ₂ gas is supplied from the separation passage to the deposition chambers for the first and second i-type layers, the amount of fluorine is small near the interface, and the change in the fluorine content in the layer thickness direction is shown in FIG. )become that way. When the transfer of the substrate was completed, all MW power supplies, RF power supplies, and target power supplies were turned off, glow discharge was stopped, and inflow of raw material gas and scavenging gas was stopped. The whole device was leaked and the wound substrate was taken out.

Next, a transparent electrode made of ITO and having a layer thickness of 70 nm was continuously formed on the second MWp type layer at 170 ° C. by a sputtering device using a roll-to-roll method.

Next, a part of this substrate is set to 50 mm × 50 mm.
The size is cut, and a carbon paste having a layer thickness of 5 μm and a line width of 0.5 mm is printed by a screen printing method, and a silver paste having a layer thickness of 10 μm and a line width of 0.5 mm is printed on the carbon paste to form a collector electrode. Formed.

The production of a tandem solar cell (SC Ex 30) using the roll-to-roll method was completed as described above. SI
When the change in the content of the valence electron control agent in the i-type layer in the layer thickness direction was examined using MS, it was found that the result was as shown in FIG. 5 (c).

(Comparative Example 30-1) First i-type layer and second layer
Of the solar cell (SC ratio 30%) under the same conditions as in Example 30 except that no PH ₃ / H ₂ gas was introduced when the i-type layer was formed.
-1) was produced.

(Comparative Example 30-2) First i-type layer and second layer
In forming the i-type layer, the solar cell (SC ratio 3) was used under the same conditions as in Example 30 except that B ₂ H ₆ / H ₂ gas was not introduced.
0-2) was prepared.

(Comparative Example 30-3) The first RFp type layer and the second RFp type layer were not formed, but the first MWp type layer and the second RFp type layer were formed.
A solar cell (SC ratio 30-3) was produced under the same conditions as in Example 30, except that the layer thicknesses of the MW p-type layers of were each 20 nm.

When the same measurement as in Example 17 was carried out,
It was found that the solar cell (SC Ex 30) of the present example had better characteristics than the conventional solar cells (SC ratio 30-1) to (SC ratio 30-3).

(Example 31) A tandem solar cell manufactured by using the deposition apparatus shown in FIG. 20 was modularized and applied to a power generation system to perform a field test.

50 mm of non-irradiated light produced in Example 30
65 x 50 mm tandem solar cells (SC Ex 14)
I prepared one. EV on a 5.0 mm thick aluminum plate
An adhesive sheet made of A was placed, a nylon sheet was placed on the sheet, and 65 solar cells were arranged on the sheet, and serialization and parallelization were performed. An EVA adhesive sheet was placed thereon, a fluororesin sheet was placed thereon, and vacuum lamination was performed to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 17. An external light that was turned on at night was used as the load, which was connected to the circuit showing the power generation system in FIG. The entire system is operated by the storage battery and the power of the module. This power generation system will be referred to as (SBS Ex 31).

(Comparative Example 31) A conventional tandem type solar cell (SC ratio 30-1) to (SC ratio 30-3), which had not been irradiated with light, was used as a module in the same manner as in Example 31, and the initial photoelectric conversion was performed. The efficiency was measured. This module was connected to the same power generation system as in Example 31. These power generation systems (SBS ratio 31-1) to (SBS ratio 31-
3).

Each module was 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 power generation system (SBS Ex 31) using the solar cell of the present invention is the same as the conventional power generation system (SB
It was found that the initial photoelectric conversion efficiency and field durability were even better than those of the S ratio 31-1) to (SBS ratio 31-3).

(Example 32) The following photovoltaic element containing oxygen and nitrogen atoms in the semiconductor layer was produced.

(Example 32-1) When forming an i-type layer,
O ₂ / He gas is 100 sccm, N ₂ / He gas is 2
A solar cell (SC Ex 32-1) was produced under the same conditions as in Example 17 except that 0 sccm was introduced.

(Example 32-2) When forming the RF-i layer, ₂ sccm of O ₂ / He gas and 1 of N ₂ / He gas were used.
A solar cell (SC Ex 32-2) was produced under the same conditions as in Example 17 except that sccm was introduced.

[Example (Part 1) According to Claim 3] (Example 32-3) O ₂ / H when forming the MWp type layer
e gas at 100 sccm, N ₂ / He gas at 20 sccc
solar cell (SC Ex 32-3) under the same conditions as in Example 17 except that O ₂ / He gas was introduced at ₂ sccm and N ₂ / He gas was introduced at 1 sccm when forming the RF p-type layer.
Was produced.

When the same measurement as in Example 17 was carried out,
The solar cells (SC Ex 32-1) to (SC Ex 32-3) are
It was found that the solar cell had better characteristics than the solar cell (SC Ex. 17).

When the concentrations of oxygen atoms and nitrogen atoms of these manufactured solar cells were examined by using SIMS, it was found that the concentrations of the introduced raw material gas (O) and the raw material gas (N) were about the same as those of the introduced raw material gas (N). It was found to be contained.

(Example 33) Using the deposition apparatus shown in FIG. 11, a solar cell having the structure shown in FIG. 1 (b) in which the Ge content in the i-type layer was changed in the layer thickness direction was produced. It was produced in the same manner as in Example 1 except for the i-type layer.

The i-type layer made of a-SiGe was formed by simultaneously performing the MWPCVD method and the sputtering of an alkali metal, as described below. First, H
300 sccm of ₂ gas is introduced and the pressure is 0.01 Tor
The temperature of the substrate 404 was set to 350 ° C. When the substrate temperature is stable, SiH ₄ gas, GeH ₄ gas, and He gas are introduced, and the SiH ₄ gas flow rate is 140 s.
ccm, GeH ₄ gas flow rate was 10 sccm, He gas flow rate was 150 sccm, H ₂ gas flow rate was 150 sccm, and the pressure inside the deposition chamber 401 was adjusted to 0.01 Torr. Next, the power of the RF power source is 0.32 W / c
It was set to m ³ and applied to the bias electrode. Then, the power of an MW power source (not shown) was set to 0.20 W / cm ³ , and the MW power was introduced into the deposition chamber through the dielectric window 413 to cause glow discharge. Next, set the target power to 2
Set to 00W, open the target shutter 417,
The shutter was opened and the formation of the i-type layer on the RF n-type layer was started. Using a computer connected to the mass flow controller, change the SiH ₄ gas flow rate and the GeH ₄ gas flow rate according to the change pattern shown in FIG.
When the i-type layer having a layer thickness of 300 nm was formed, the shutter and the target shutter were closed, the MW power supply, the RF power supply and the target power supply were turned off to stop the glow discharge, and the formation of the i-type layer was completed.

This solar cell is called (SC Ex 33), and Table 7 shows the conditions for forming the RFn-type layer, the i-type layer, the RFp-type layer, and the MWp-type layer.

(Comparative Example 33-1) When forming the i-type layer, the flow rate of SiH ₄ gas and GeH _{4 were changed} according to FIG.
A solar cell (SC ratio 33-1) was produced under the same conditions as in Example 33 except that the gas flow rate was changed.

(Comparative Example 33-2) A solar cell was formed under the same conditions as in Example 33 except that the SiH ₄ gas flow rate was 120 sccm and the GeH ₄ gas flow rate was 30 sccm when the i-type layer was formed. A battery (SC ratio 33-2) was produced.

Comparative Example 33-3 Example 3 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 33-3) was produced under the same conditions as in No. 3.

Solar cell (SC Ex 33) and (SC ratio 33
-1) to (SC ratio 33-3) were produced in six pieces, and initial photoelectric conversion efficiency (photovoltaic power / incident optical power), vibration deterioration, light deterioration, and bias voltage application were performed in the same manner as in Example 1. We measured vibration deterioration and light deterioration in high temperature and high humidity environment.

As a result of the initial photoelectric conversion efficiency measurement,
3), (SC ratio 33-1), (SC ratio 33-
The initial photoelectric conversion efficiency of 2) was as follows.

(SC ratio 33-1) 0.88 times (SC ratio 33-2) 0.92 times (SC ratio 33-3) 0.90 times Vibration deterioration and light deterioration measurement results (SC Ex 33) On the other hand, the (SC ratio 33-1) to (SC ratio 33-3) showed the following reduction rates in the photoelectric conversion efficiency after photodegradation and in the photoelectric conversion efficiency after vibration degradation.

Vibration deterioration Photodegradation (SC ratio 33-1) 0.88 times 0.86 times (SC ratio 33-2) 0.91 times 0.88 times (SC ratio 33-3) 0.91 times 0. 88 times Next, vibration deterioration and light deterioration in a high temperature and high humidity environment when a bias was applied were measured. As a result of measurement, (SC
(SC ratio 33-1) to (SC ratio 33)
The decrease rate of the photoelectric conversion efficiency after the vibration deterioration of (3) and the decrease rate of the photoelectric conversion efficiency after the light deterioration were as follows.

Vibration deterioration Light deterioration (SC ratio 33-1) 0.87 times 0.87 times (SC ratio 33-2) 0.89 times 0.91 times (SC ratio 33-3) 0.88 times 89 times The state of layer delamination was observed using an optical microscope. In (SC Ex. 33), (SC ratio 33-1), and (SC ratio 33-2), no layer peeling was observed, but in (SC ratio 33-3), slight layer delamination was observed.

Next, using a glass substrate and a stainless substrate,
A sample was prepared in which the SiH ₄ gas flow rate and the GeH ₄ gas flow rate were made constant over time. Constant flow rate, layer thickness 1μ
A sample of the i-type layer was prepared under the same conditions as in Example 33 except that m was set. Furthermore, several samples were prepared with various flow rates. The band gap (Eg) of the glass substrate sample produced using a spectrophotometer was determined, and the Ge content of the stainless substrate sample was analyzed using an Auger electron spectroscopy analyzer (AES). Using the results of both, the relationship between the Ge content in the i-type layer and the band gap was obtained.

It was also produced by using AES (SC Ex. 3
3) and (SC ratio 33-3), the change in the Ge content in the layer thickness direction was obtained, and the result was as shown in FIG.

Similarly, when the change of the Ge content and the band gap of (SC ratio 33-1) was obtained, it was as shown in FIG. 17 (d). Similarly, when the Ge content of (SC ratio 33-2) was obtained, it was found that there was no change in the Ge content with respect to the layer thickness direction, it was constant, and the band gap was 1.51 (eV).

Thus, the Ge content in the layer thickness direction,
It was found that the change in the band gap and the band gap depended on the GeH ₄ gas flow rate introduced.

Further, the vibration deterioration and the light deterioration in the high temperature environment and the vibration deterioration and the light deterioration in the high humidity environment were measured. Similarly, (SC Ex 33) is (SC ratio 33-1) to
(SC ratio 33-3) had better characteristics.

Further, even when a forward bias is applied in the above environment, (SC ex. 33) is similarly (SC ratio 33-1).
~ (SC ratio 33-3) had better characteristics.

As described above, the solar cell of this example (SC Ex 33) is the same as the conventional solar cells (SC ratio 33-1) to (SC).
It has been found that it has a further excellent characteristic than the ratio 33-3).

Example 34 A solar cell (SC Ex 2) in which the Ge content and the alkali metal content in the i-type layer varied as shown in FIG. 6B was produced. A solar cell (SC Ex 34) was produced under the same conditions as in Example 33 except that the GeH ₄ gas flow rate monotonously increased with time, the SiH ₄ gas monotonically decreased with time, and the target power monotonically increased. When the change of the band gap in the layer thickness direction was obtained by the same method as in Example 33, it was found that the result was as shown in FIG. 7B.

The same measurement as in Example 33 was carried out.
It has been found that the solar cell of (SC Ex. 34) has more excellent characteristics than the conventional solar cells (SC ratio 33-1) to (SC ratio 33-3) as in Example 33.

Example 35 A photodiode (PD real 35) having the layer structure shown in FIG. 1C was manufactured.

First, a substrate was manufactured. 0.5m thickness
m, 20 × 20 mm ² glass substrate was ultrasonically washed with acetone and isopropanol, dried with warm air, and a light-reflecting layer of Al having a layer thickness of 0.1 μm was formed on the glass substrate surface at room temperature by vacuum deposition. The fabrication of the substrate was completed.

MWn was formed on the substrate in the same manner as in Example 33.
The type layer (a-SiC), the RFn type layer (a-SiC), the i-type layer (a-SiGe), and the RFp-type layer (a-SiC) were sequentially formed. Table 8 shows the layer forming conditions of the semiconductor layer.

Then, a transparent electrode and a collector electrode were formed on the RF p-type layer in the same manner as in Example 33.

(Comparative Example 35-1) When forming the i-type layer, the flow rate of SiH ₄ gas and GeH _{4 were changed} according to FIG.
A photodiode (PD ratio 35-1) was produced under the same conditions as in Example 33 except that the gas flow rate was changed and the band gap was changed as shown in FIG.

Comparative Example 35-2 Example 3 was repeated except that the RFn type layer was not formed and the MWn type layer had a layer thickness of 40 nm.
A photodiode (PD ratio 35-2) was manufactured under the same conditions as described above.

The on / off ratio of the manufactured photodiode was measured. Next, the same measurement as in Example 33 was performed for the on / off ratio. As a result, the photodiode (PD actual 35) of this embodiment is the same as the conventional photodiode (PD ratio 3).
5-1), it was found that it has more excellent characteristics than (PD ratio 35-2).

Example 36 A solar cell of FIG. 1B having a nip type structure in which the stacking order of the n type layer and the p type layer was reversed was produced. Similarly to Example 33, the RFp type layer (μc-Si), the i type layer (a-SiGe), the RFn type layer (a-SiC), and the MWn type layer (a-SiC) were formed on the substrate.

When forming the i-type layer, the SiH ₄ gas flow rate and the GeH ₄ gas flow rate are temporally changed as shown in FIG. 17 (b) so that the position where the Ge content becomes maximum is the center of the i-type layer. It was set closer to the p-type layer side. Table 9 shows the conditions for forming the semiconductor layer. A solar cell (SC Ex 36) was produced under the same conditions as in Example 33 except for the semiconductor layer and the substrate.

(Comparative Example 36-1) When forming the i-type layer, as shown in FIG. 17A, SiH ₄ gas flow rate and GeH ₄ gas flow rate were set.
A solar cell (SC ratio 36-1) was produced under the same conditions as in Example 36 except that the gas flow rate was changed.

Comparative Example 36-2 Example 3 was repeated except that the RFn type layer was not formed and the MWn type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 36-2) was produced under the same conditions as in No. 6.

When the same measurement as in Example 33 was carried out,
It was found that the solar cell (SC Ex 36) of the present example had better characteristics than the conventional solar cells (SC ratio 36-1) and (SC ratio 36-2).

(Example 37) A solar cell in which fluorine was contained in the i-type layer and the fluorine content was minimum near the interface was produced. When forming the i-type layer, GeF ₄ gas was introduced instead of GeH ₄ gas, and SiH ₄ gas was used as in Example 33.
The gas flow rate and the GeF ₄ gas flow rate were changed with time to obtain a solar cell in which the fluorine content changed as shown in FIG. 10A and the Ge content changed as shown in FIG. 17C. Except for this, it was manufactured under the same conditions as in Example 33. When the same measurement as in Example 33 was performed, it was found that the solar cell (SC Ex. 37) had better characteristics than (SC Ex. 33). No delamination was observed.

Example 38 A solar cell having the maximum hydrogen content near the interface of the MWp type layer and near the interface of the RFp type layer was produced. When the MWp type layer was formed, the MW electric power was changed with time, and when the RFp type layer was formed, the RF electric power was changed with time to obtain a change pattern of the hydrogen content as shown in FIG. Except for this, it was manufactured under the same conditions as in Example 33. When the same measurement as in Example 33 was performed, it was found that the solar cell (SC Ex. 38) had better characteristics than (SC Ex. 33).

Example 39 A solar cell having the maximum content of the valence electron control agent near the interface between the MWp type layer and the RFp type layer was produced. When forming the MWp type layer and the RFp type layer, the raw material gas of the valence electron control agent introduced was changed with time to change the content of B atoms as shown in FIG. Except for this, it was manufactured under the same conditions as in Example 33. When the same measurement as in Example 33 was performed, it was confirmed that the solar cell (SC
It was found that Ex. 39) had even better properties than (SC Ex. 33).

(Embodiment 40) Having the structure of FIG.
Moreover, a solar cell (SC Ex 40) was produced in which the content of the valence electron control agent in the i-type layer changed smoothly in the layer thickness direction and the content increased on the p-type layer side. When the i-type layer is formed, the PH ₃ / H ₂ gas flow rate and the B ₂ H ₆ / H ₂ gas flow rate are changed with time so that the P and B atom contents are as shown in FIG. 5C. Was manufactured under the same conditions as in Example 33.

When the same measurement as in Example 33 was carried out,
It was found that the solar cell (SC Ex 40) had even better characteristics than (SC Ex 33).

(Example 41) A solar cell (SC Ex 41) having MWp type layer and RFp type layer containing fluorine was produced. When forming the MWp type layer and the RFp type layer, a new S
By introducing iF ₄ and changing the flow rate with time, the change in the fluorine content in the layer thickness direction was set as shown in FIG. Except for this, it was manufactured under the same conditions as in Example 33. When the same measurement as in Example 33 was performed, it was confirmed that the solar cell (SC
It was found that Ex 41) had even better characteristics than (SC Ex 33).

(Example 42) Using a-SiSn for the i-type layer
Alkali metal was added using the MWPCVD method.
A solar cell was produced. First, the target and tar in Figure 11.
Get the electrode and target shutter from the deposition chamber
I removed it. When forming the i-type layer, GeH_FourInstead of gas
SnH_FourGas was used and bubbling was newly performed with He gas.
LiH₂PO _Four/ He gas was used. In addition, FIG.
SiH with the same change pattern as (a)_FourGas flow time
Change, SnH_FourThe gas flow rate is GeH in FIG.
_FourAs with the gas flow rate change, it changes with time, and LiH₂PO_Four
/ He gas flow rate is changed with time to remove alkali metal
The quantity was set as shown in FIG. 6 (a). Other conditions are examples
A solar cell (SC Ex 42) was produced under the same conditions as 33.

(Comparative Example 42-1) When forming the i-type layer,
The SiH ₄ gas flow rate and the SnH ₄ gas gas flow rate were constant over time, and were set to 120 sccm and 30 sccm, respectively.
-1) was produced.

(Comparative Example 42-2) Example 4 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 42-2) was produced under the same conditions as in 2.

When the same measurement as in Example 33 was carried out,
The solar cell (SC Ex 42) of this example is a solar cell (SC
It was found that the characteristics were more excellent than those of the ratios 42-1) and (SC ratio 42-2).

Example 43 A solar cell containing lithium, sodium and potassium as alkali metals was produced. First, as a target, LiF, NaF,
When KF was replaced with a mixture of 10: 5: 1 and an i-type layer was formed, the SiH ₄ gas flow rate was 110 sccm and S
iF ₄ gas flow rate is 20 sccm, GeH ₄ gas flow rate is 2
0 sccm, the MW power and the target power were changed with time, and the change pattern of the Ge content and the alkali metal content was changed to that shown in FIG. 6C. ) Was produced. When the band gap in the layer thickness direction was obtained, it was found that it was as shown in FIG. 7 (c).

When the same measurement as in Example 33 was carried out, the solar cell of this example (SC Ex 43) was further improved than the conventional solar cells (SC ratio 33-1) to (SC ratio 33-3). It has been found to have excellent properties.

(Example 44) Between the RF p-type layer and the i-type layer,
And a PR-i layer between the RF n-type layer and the i-type layer.
The solar cell of (c) was produced. Example 40: other layers
A solar cell was produced in the same manner as in. The two RF-i layers are made of a-Si, and the SiH ₄ gas flow rate is 2 sccm,
SiF ₄ gas flow rate is 0.5 sccm, H ₂ gas flow rate is 5
0 sccm, pressure inside the deposition chamber is 1.0 Torr, RF power to be introduced is 0.01 W / cm ³ , substrate temperature is 270
It was formed under the conditions of the temperature of 20 ° C. and the layer thickness of 20 nm. When the same measurement as in Example 33 was performed, it was found that the solar cell (SC Ex. 44) had further excellent characteristics as compared to (SC Ex. 40).

Example 45 A triple type solar cell shown in FIG. 14 was produced using the deposition apparatus of FIG. 11 using the MWPCVD method.

First, in the same manner as in Example 13, a light reflecting layer and a reflection increasing layer were formed on a stainless steel substrate.

Then, a first MWn type layer (μc-Si) was formed on the substrate by the same method as in Example 33, and further, the first RFn type layer (a-Si) and the first i type layer were formed. (A-SiG
e), the first RF p-type layer (a-Si layer thickness 10 nm),
First MW p-type layer (μc-Si layer thickness 10 nm), second RFn-type layer (μc-Si), second i-type layer (a-S)
i), the second RF p-type layer (a-SiC layer thickness 10n)
m), the second MWp type layer (μc-SiC layer thickness 10n)
m), the third RFn-type layer (a-SiC), the third i-type layer (a-SiC), the third RFp-type layer (a-SiC layer thickness 10 nm), the third MWp-type layer (μc). -SiC layer thickness 1
0 nm) was sequentially formed.

The target was exchanged with NaF, each semiconductor layer was allowed to contain Na, and the change in the content was set as shown in FIG. 6 (c). When forming each semiconductor layer, a new Si layer is formed.
Introducing F ₄ gas and changing the fluorine content in the layer thickness direction
Like 0 (c). When forming the first i-type layer, S
The iH ₄ gas flow rate and the GeH ₄ gas flow rate were changed with time as shown in FIG. In other layers, MWPCVD
In the layer formed by the method, the MW power is changed with time during the formation, and in the layer formed by the RFPCVD method, the RF power is changed with the time during formation, and the distribution of the hydrogen content of each layer is shown in FIG.
(C).

Next, on the third MWp type layer, transparent electrodes and current collecting electrodes similar to those of Example 33 were formed.

[0475] With the above, the triple type solar cell (SC Ex 45)
Has been completed.

(Comparative Example 45-1) A first i-type layer is formed.
As shown in FIG. 17 (b), the SiH_FourGas flow rate, GeH
_FourSame as Example 45 except that the gas flow rate is changed with time
A solar cell (SC ratio 45-1) was produced under the conditions.

(Comparative Example 45-2) The first RFp type layer, the second RFp type layer, and the third RFp type layer were not formed, but the first MWp type layer and the second MWp type layer were formed. A solar cell (SC ratio 45-2) was produced under the same conditions as in Example 45 except that the layer and the third MWp type layer had a layer thickness of 20 nm.

When the same measurement as in Example 33 was carried out,
The solar cell (SC Ex 45) of this example is a solar cell (SC
It was found that the characteristics are further superior to those of the ratio 45-1) and (SC ratio 45-2).

Example 46 A tandem solar cell shown in FIG. 15 was produced using the deposition apparatus using the roll-to-roll method shown in FIG.

In the same manner as in Example 14, a light reflecting layer and a reflection increasing layer were continuously formed on a long stainless steel sheet.

A first MWn type layer (μc-Si layer thickness 20 nm) is formed on the substrate in the deposition chamber 901, and a first RFn type layer (a-Si layer thickness 10 n) is further formed in the deposition chamber 902.
m), the first i-type layer (a-SiGe layer thickness 180 nm) in the deposition chamber 903, and the first RFp-type layer (a) in the deposition chamber 904.
-Si layer thickness 10 nm), first MWp in deposition chamber 905
Type layer (μc-Si layer thickness 10 nm), the second RFn type layer (μc-Si layer thickness 20 nm) in the deposition chamber 906, the second i-type layer (a-Si layer thickness 250 nm) in the deposition chamber 907,
In the deposition chamber 908, the second RF p-type layer (a-SiC layer thickness 1
0 nm), the second MWp-type layer (μc-S) in the deposition chamber 909.
The iC layer thickness of 10 nm) was sequentially formed.

Na is contained in the first i-type layer and the second i-type layer, and the change in the layer thickness direction is shown in FIG. 6 (c). SiH ₄ gas and SiF ₄ gas were used to form the semiconductor layers, and fluorine was contained in all the semiconductor layers. As shown in FIG. 21B, the raw material gas inlet of the deposition chamber 903 for forming the first i-type layer is divided into a plurality of portions, and SiH ₄ gas, SiF ₄ gas, GeH ₄ gas, H ₂ are introduced from the respective inlets. Gas was flowed in. When forming the i-type layer, each mass flow controller adjusted the change pattern of the GeH ₄ gas flow rate with respect to the substrate transport direction to be the change pattern of the arrow 960 in FIG. By doing so, the change in the Ge content of the i-type layer in the layer thickness direction was as shown in FIG. 6 (c).

When the transfer of the substrate was completed, all MW power supplies, RF power supplies and target power supplies were turned off, glow discharge was stopped, and inflow of raw material gas and scavenging gas was stopped. The whole device was leaked and the wound substrate was taken out.

Next, a transparent electrode made of ITO having a layer thickness of 70 nm was continuously formed at 170 ° C. on the second MWp type layer. Subsequently, a part of this substrate is cut into a size of 50 mm × 50 mm, and a layer thickness of 5 μm and a line width of 0.5 mm are obtained by a screen printing method.
Print the carbon paste of
A silver paste having a line width of 0.5 mm was printed to form a collector electrode.

Thus, the production of the tandem solar cell (SC Ex 46) using the roll-to-roll method was completed.

(Comparative Example 46-1) A solar cell (SC) was formed under the same conditions as in Example 46 except that the GeH ₄ gas flow rate was constant with respect to the substrate transport direction when the first i-type layer was formed.
Ratio 46-1) was produced.

(Comparative Example 46-2) The first RFp type layer and the second RFp type layer were not formed, and the first MWp type layer,
Also, a solar cell (SC ratio 46-2) was produced under the same conditions as in Example 46 except that the layer thickness of the second MWp type layer was 20 nm.

When the same measurement as in Example 33 was carried out,
The solar cell (SC Ex 46) of the present embodiment is a solar cell (SC
It was found that the characteristics are further superior to those of the ratio 46-1) and (SC ratio 46-2).

(Example 47) A tandem solar cell manufactured by using the deposition apparatus shown in FIG. 20 was modularized and applied to a power generation system to perform a field test.

50 mm of non-irradiated light produced in Example 46
65 x 50 mm tandem solar cell (SC Ex 46)
I prepared one. EV on a 5.0 mm thick aluminum plate
An adhesive sheet made of A was placed, a nylon sheet was placed on the sheet, and 65 solar cells were arranged on the sheet, and serialization and parallelization were performed. An EVA adhesive sheet was placed thereon, a fluororesin sheet was placed thereon, and vacuum lamination was performed to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured by the same method as in Example 33. An external light that was turned on at night was used as the load, which was connected to the circuit showing the power generation system in FIG. The entire system is operated by the storage battery and the power of the module. This power generation system will be called (SBS Ex 47).

(Comparative Example 47) A conventional tandem-type solar cell (SC ratio 46-1) and 66 (SC ratio 46-2) which were not irradiated with light were modularized in the same manner as in Example 47, and initial photoelectric conversion was performed. The efficiency was measured. This module was connected to a power generation system similar to that in Example 47. These power generation systems (SBS ratio 47-1), (SBS ratio 47-
2).

Each module was 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 power generation system (SBS Ex 47) using the solar cell of the present invention is the same as the conventional power generation system (SB
It was found that the initial photoelectric conversion efficiency and field durability were even better than those of the S ratio 47-1) and (SBS ratio 47-2).

(Example 48) The following photovoltaic element having oxygen and nitrogen atoms in the semiconductor layer was produced.

(Example 48-1) When forming an i-type layer,
O ₂ / He gas is 100 sccm, N ₂ / He gas is 2
A solar cell (SC Ex 48-1) was produced under the same conditions as in Example 33 except that 0 sccm was introduced.

(Example 48-2) When forming the RF-i layer, ₂ sccm of O ₂ / He gas and 1 of N ₂ / He gas were used.
A solar cell (SC Ex 48-2) was produced under the same conditions as in Example 33 except that sccm was introduced.

(Example 48-3) O ₂ / He gas of 100 sccm and N ₂ / He gas of 20 sccm were introduced at the time of forming the MW p-type layer, and O _{2 at} the time of forming the RF p-type layer.
/ He gas ₂ sccm, N ₂ / He gas 1 sccm
A solar cell (SC
Example 48-3) was produced.

When the same measurement as in Example 33 was carried out,
The solar cells (SC Ex 48-1) to (SC Ex 48-3) are
It was found that the solar cell (SC Ex. 33) had even better characteristics.

When the concentrations of oxygen atoms and nitrogen atoms of these fabricated solar cells were examined using SIMS, it was found that the concentrations of the introduced raw material gas (O) and the raw material gas (N) were about the same as those of the introduced raw material gas (N). It was found to be contained.

[Example (Part 2) According to Claim 3] (Example 49) [0500] Using the deposition apparatus shown in Fig. 11, the content of C in the i-type layer was changed in the layer thickness direction. A solar cell having the configuration b) was produced. It was produced in the same manner as in Example 1 except for the i-type layer.

The i-type layer made of a-SiC was formed by simultaneously performing the MWPCVD method and the sputtering of an alkali metal, as described below. First, H ₂
Gas is introduced at 300 sccm and the pressure is 0.01 Tor
The temperature of the substrate 404 was set to 350 ° C. When the substrate temperature became stable, SiH ₄ gas, CH ₄ gas, and He gas were introduced, and the SiH ₄ gas flow rate was 120 s.
ccm, CH ₄ gas flow rate was 30 sccm, He gas flow rate was 150 sccm, H ₂ gas flow rate was 150 sccm, and the pressure inside the deposition chamber 401 was adjusted to 0.01 Torr. Next, the power of the RF power source is 0.32 W / c
It was set to m ³ and applied to the bias electrode. Then, the power of an MW power source (not shown) was set to 0.20 W / cm ³ , and the MW power was introduced into the deposition chamber through the dielectric window 413 to cause glow discharge. Next, set the target power to 2
Set to 00W, open the target shutter 417,
The shutter was opened and the formation of the i-type layer on the RF n-type layer was started. A computer connected to the mass flow controller was used to change the SiH ₄ gas flow rate and the CH ₄ gas flow rate according to the change pattern shown in FIG. 18A to form an i-type layer having a layer thickness of 300 nm. Was closed, the MW power supply, the RF power supply, and the target power supply were turned off to stop the glow discharge, and the formation of the i-type layer was completed.

This solar cell will be called (SC Ex 49), and Table 10 shows the conditions for forming the RFn-type layer, the i-type layer, the RFp-type layer, and the MWp-type layer.

(Comparative Example 49-1) A solar cell (Example 49-1) was prepared under the same conditions as in Example 49 except that the SiH ₄ gas flow rate and the CH ₄ gas flow rate were changed in accordance with FIG. 18 (b) when the i-type layer was formed. SC ratio 49-1) was produced.

(Comparative Example 49-2) A solar cell was prepared under the same conditions as in Example 49 except that the SiH ₄ gas flow rate was 130 sccm and the CH ₄ gas flow rate was 20 sccm when the i-type layer was formed. A battery (SC ratio 49-2) was produced.

(Comparative Example 49-3) Example 4 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 49-3) was produced under the same conditions as in 9.

Solar cell (SC Ex 49) and (SC Comp Ex 49
-1) to (SC ratio 49-3) were produced in six pieces, and in the same manner as in Example 1, initial photoelectric conversion efficiency (photovoltaic power / incident optical power), vibration deterioration, light deterioration, and bias voltage application. We measured vibration deterioration and light deterioration in high temperature and high humidity environment.

As a result of the initial photoelectric conversion efficiency measurement, (SC Ex 4
9), (SC ratio 49-1), (SC ratio 49-
The initial photoelectric conversion efficiency of 2) was as follows.

(SC ratio 49-1) 0.85 times (SC ratio 49-2) 0.87 times (SC ratio 49-3) 0.88 times Vibration deterioration and light deterioration measurement results (SC actual 49) On the other hand, (SC ratio 49-1) to (SC ratio 49-3) showed the following reduction rates of the photoelectric conversion efficiency after photodegradation and the photoelectric conversion efficiency after vibration degradation.

Vibration deterioration Photodegradation (SC ratio 49-1) 0.86 times 0.84 times (SC ratio 49-2) 0.87 times 0.85 times (SC ratio 49-3) 0.88 times 0. 85 times Next, vibration deterioration and light deterioration in a high temperature and high humidity environment when a bias was applied were measured. As a result of measurement, (SC
(SC ratio 49-1) to (SC ratio 49)
The decrease rate of the photoelectric conversion efficiency after the vibration deterioration of (3) and the decrease rate of the photoelectric conversion efficiency after the light deterioration were as follows.

Vibration deterioration Light deterioration (SC ratio 49-1) 0.83 times 0.84 times (SC ratio 49-2) 0.86 times 0.87 times (SC ratio 49-3) 0.85 times The state of delamination was observed using an 85 times optical microscope. In (SC Ex 49), (SC Ratio 49-1), and (SC Ratio 49-2), no layer delamination was observed, but in (SC Ratio 49-3), a slight layer delamination was observed.

Next, using a glass substrate and a stainless substrate,
A sample was prepared in which the SiH ₄ gas and the CH ₄ gas were kept constant over time. An i-type layer sample was prepared under the same conditions as in Example 49 except that the flow rate was constant and the layer thickness was 1 μm. Furthermore, several samples were prepared with various flow rates. The band gap (Eg) of the glass substrate sample produced using a spectrophotometer was determined, and further, the C content of the stainless substrate sample was analyzed using an Auger electron spectroscopy analyzer (AES). Using the results of both, the relationship between the C content in the i-type layer and the band gap was obtained.

It was also produced using AES (SC Ex. 4
9) and (SC ratio 49-3), the change of the Ge content and the change of the band gap with respect to the layer thickness direction were obtained.
It became like 8 (c).

Similarly, the change in the C content and band gap (SC ratio 49-1) was determined, and the result was as shown in FIG. 18 (d). Similarly, when the C content of (SC ratio 49-2) was determined, there was no change in the C content in the layer thickness direction,
At constant, the bandgap was found to be 1.92 (eV).

As described above, it was found that the changes in the C content and the band gap in the layer thickness direction depend on the CH ₄ gas flow rate introduced.

As described above, the solar cell of this example (SC Ex 49) is the same as the conventional solar cells (SC ratio 49-1) to (SC).
It has been found that it has even better characteristics than the ratio 49-3).

(Example 50) The C content in the i-type layer is as shown in FIG.
A solar cell (SC Ex 50) having a variation as shown in (b) was produced. A solar cell (SC Ex 50) was produced under the same conditions as in Example 49 except that the CH ₄ gas flow rate was monotonically decreased with time and the SiH ₄ gas was monotonically increased with time. When the change in the band gap in the layer thickness direction was obtained by the same method as in Example 49, it was found that it was as shown in FIG. 9B.

[0517] When the same measurement as in Example 49 was carried out,
It has been found that the solar cell of (SC Ex 50) has further excellent characteristics as in Example 49, compared to the conventional solar cells (SC ratio 49-1) to (SC ratio 49-3).

Example 51 A photodiode (PD actual 51) having the layer structure shown in FIG. 1C was manufactured.

First, a substrate was manufactured. 0.5m thickness
m, 20 × 20 mm ² glass substrate was ultrasonically washed with acetone and isopropanol, dried with warm air, and a light-reflecting layer of Al having a layer thickness of 0.1 μm was formed on the glass substrate surface at room temperature by vacuum deposition. The fabrication of the substrate was completed.

MWn is formed on the substrate in the same manner as in Example 49.
Type layer (μc-SiC), RFn type layer (a-SiC), i
The mold layer (a-SiC) and the RFp type layer (μc-SiC) were sequentially formed. Table 11 shows the layer forming conditions of the semiconductor layer.

Then, a transparent electrode and a collector electrode were formed on the RF p-type layer in the same manner as in Example 49.

(Comparative Example 51-1) When forming the i-type layer, the flow rate of SiH ₄ gas and GeH _{4 were changed} according to FIG. 18 (b).
A photodiode (PD ratio 51-1) was produced under the same conditions as in Example 49 except that the gas flow rate was changed and the band gap was changed as shown in FIG.

(Comparative Example 51-2) When forming an i-type layer, the SiH ₄ gas flow rate was 130 sccm, the CH ₄ gas flow rate was 20 sccm, and the C content and band gap in the layer thickness direction were constant. A photodiode (PD ratio 51-
2) was produced.

(Comparative Example 51-3) Example 3 was repeated except that the RFn type layer was not formed and the MWn type layer had a layer thickness of 40 nm.
A photodiode (PD ratio 51-3) was manufactured under the same conditions as described above.

[0525] The on / off ratio of the manufactured photodiode was measured. Next, the same measurement as in Example 49 was performed for the on / off ratio. As a result, the photodiode (actual PD 51) of this embodiment is the same as the conventional photodiode (PD ratio 5).
It was found that the characteristics are further superior to those of 1-1) to (PD ratio 51-3).

(Example 52) Stacking order of n-type layer and p-type layer
1b having a nip type structure in which
I made a pond. RFp type layer on the substrate as in Example 49
(Μc-Si), i-type layer (a-SiC), RFn-type layer
(A-SiC), MWn type layer (a-SiC) is formed
It was When forming the i-type layer, as shown in FIG.
_FourGas flow rate, CH _FourBy changing the gas flow rate over time, C
The position where the content is the minimum is on the p-type layer side from the center of the i-type layer
I tried to be. Table 12 shows the conditions for forming the semiconductor layer.
The layers other than the semiconductor layer and the substrate were formed under the same conditions as in Example 49.
A solar cell (SC Ex 52) was produced.

(Comparative Example 52-1) When forming the i-type layer, as shown in FIG. 18A, the SiH ₄ gas flow rate and GeH ₄ gas flow rate were changed.
A solar cell (SC ratio 52-1) was produced under the same conditions as in Example 52 except that the gas flow rate was changed.

(Comparative Example 52-2) A solar cell was formed under the same conditions as in Example 52 except that the SiH ₄ gas flow rate was 130 sccm and the CH ₄ gas flow rate was 20 sccm when forming the i-type layer. A battery (SC ratio 52-2) was produced.

Comparative Example 52-3 Example 5 was repeated except that the RFn type layer was not formed and the MWn type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 52-2) was produced under the same conditions as in 2.

When the same measurement as in Example 49 was carried out,
It was found that the solar cell (SC Ex 52) of the present example has more excellent characteristics than the conventional solar cells (SC ratio 52-1) to (SC ratio 52-3).

(Example 53) A solar cell having a minimum fluorine content in the vicinity of the interface was manufactured by incorporating fluorine into the i-type layer. When the i-type layer is formed, CF ₄ gas is newly introduced, and the CF ₄ gas flow rate is temporally changed to change the fluorine content as shown in FIG. 10A and the C content as shown in FIG. The solar cell which changes like (c) was obtained. The other conditions were the same as in Example 49. When the same measurement as in Example 49 was performed, the solar cell (SC Ex 53) showed (S
It has been found that it has even better characteristics than C Ex. 49).

Example 54 A solar cell having a maximum hydrogen content near the interface between the MWp type layer and the RFp type layer was produced. The MW electric power was changed with time when forming the MWp type layer, and the RF electric power was changed with time when forming the RFp type layer to obtain a change pattern of the hydrogen content as shown in FIG. 3B. The other conditions were the same as in Example 49. When the same measurement as in Example 49 was performed, it was found that the solar cell (SC Ex. 54) had further excellent characteristics than (SC Ex. 49).

(Example 55) A valence electron control agent serving as a donor and an valence electron control agent serving as an acceptor of the i-type layer were both contained, and the content of the valence electron control agent near the interface between the MWp-type layer and the RFp-type layer. A solar cell having the maximum value was manufactured. i
When forming the mold layer, PH ₃ / H ₂ gas and B ₂ H ₆ / H are newly added.
By introducing ₂ gases and changing the flow rate with time, the contents of P and B atoms were changed as shown in FIG. When forming the MWp-type layer and the RFp-type layer, the B ₂ H ₆ / H ₂ gas was changed with time to change the content of B atoms as shown in FIG. The other conditions were the same as in Example 49. When the same measurement as in Example 49 was performed, it was found that the solar cell (SC Ex. 55) had further excellent characteristics than (SC Ex. 49).

(Embodiment 56) Having the structure of FIG. 1 (a),
Moreover, a solar cell (SC Ex 56) was produced in which the hydrogen content in the i-type layer changed smoothly in the layer thickness direction and the hydrogen content increased near the interface. RF when forming the i-type layer
It was manufactured under the same conditions as in Example 49 except that the electric power was changed with time so that the hydrogen content was as shown in FIG.

When the same measurement as in Example 49 was carried out,
It was found that the solar cell (SC Ex 56) had even better characteristics than (SC Ex 49).

Example 57 A solar cell (SC Ex 57) was prepared in which the MWp type layer and the RFp type layer contained fluorine. When forming the MWp type layer and the RFp type layer, B is newly added.
The F ₃ / H ₂ gas was introduced, and the flow rate was temporally changed to change the fluorine content in the layer thickness direction as shown in FIG. In addition, the B ₂ H ₆ / H ₂ gas flow rate was also changed with time to change the B content in the layer thickness direction as shown in FIG. The other conditions were the same as in Example 49.
When the same measurement as in Example 49 was performed, it was found that the solar cell (SC Ex. 57) had better characteristics than (SC Ex. 49).

Example 58 An a-SiGeC was used for the i-type layer, and a solar cell containing an alkali metal was prepared by the MWPCVD method. First, the target, target electrode, and target shutter shown in FIG. 11 were removed from the deposition chamber. At the time of forming the i-type layer, LiH ₂ PO ₄ / He gas bubbled with He gas was newly used, and the SiH ₄ and CH ₄ gas flow rates were changed with time in the same change pattern as in FIG. 18 (a). The GeH ₄ gas flow rate is shown in FIG.
As in the case of the GeH ₄ gas flow rate change of (a), it is changed over time,
By changing the LiH ₂ PO ₄ / He gas flow rate with time,
The alkali metal content was set as shown in FIG. Other conditions are the same as in Example 49.
8) was produced.

(Comparative Example 58-1) When forming an i-type layer,
A solar cell (SC ratio 58-1) was produced under the same conditions as in Example 58, except that the CH ₄ gas flow rate and the GeH ₄ gas flow rate were constant over time and were 5 sccm and 7 sccm, respectively.

(Comparative Example 58-2) Example 5 was repeated except that the RFp type layer was not formed and the MWp type layer had a layer thickness of 20 nm.
A solar cell (SC ratio 58-2) was produced under the same conditions as in Example 8.

When the same measurement as in Example 49 was carried out,
The solar cell (SC Ex 58) of the present embodiment is the solar cell (SC
It was found that the characteristics were further superior to those of the ratio 58-1) and (SC ratio 58-2).

Example 59 A solar cell was prepared in which the i-type layer contained lithium, sodium, and potassium as alkali metals. First, LiF as a target,
When changing the mixture of NaF and KF to 10: 5: 1 and forming the i-type layer, the target electric power is changed with time, and the change pattern of the alkali metal content is shown in FIG. 8 (c).
A solar cell (SC Ex 59) was produced under the same conditions as in Example 49 except for the above.

When the same measurement as in Example 49 was carried out, the solar cell of this example (SC Ex 59) was further improved than the conventional solar cells (SC ratio 49-1) to (SC ratio 49-3). It has been found to have excellent properties.

(Example 60) Between an RF p-type layer and an i-type layer,
And a PR-i layer between the RF n-type layer and the i-type layer.
The solar cell of (c) was produced. Example 56: other layers
A solar cell was produced in the same manner as in. The two RF-i layers are made of a-Si, and the SiH ₄ gas flow rate is 2 sccm,
SiF ₄ gas flow rate is 0.5 sccm, H ₂ gas flow rate is 5
0 sccm, pressure inside the deposition chamber is 1.0 Torr, RF power to be introduced is 0.01 W / cm ³ , substrate temperature is 270
It was formed under the conditions of the temperature of 20 ° C. and the layer thickness of 20 nm. When the same measurement as in Example 49 was performed, it was found that the solar cell (SC Ex. 60) had further superior characteristics to (SC Ex. 56).

Example 61 A triple type solar cell shown in FIG. 14 was produced using the deposition apparatus of FIG. 11 using the MWPCVD method.

First, in the same manner as in Example 13, a light reflecting layer and a reflection increasing layer were formed on a stainless steel substrate.

Next, a first MWn type layer (μc-Si) is formed on the substrate by the same method as in Example 49, and further a first RFn type layer (a-Si) and a first i type layer are formed. (A-SiG
e), the first RF p-type layer (a-Si layer thickness 10 nm),
First MW p-type layer (μc-Si layer thickness 10 nm), second RFn-type layer (μc-Si), second i-type layer (a-S)
i), the second RF p-type layer (a-SiC layer thickness 10n)
m), the second MWp type layer (μc-SiC layer thickness 10n)
m), the third RFn-type layer (a-SiC), the third i-type layer (a-SiC), the third RFp-type layer (a-SiC layer thickness 10 nm), the third MWp-type layer (μc). -SiC layer thickness 1
0 nm) was sequentially formed.

The target was exchanged for NaF, each semiconductor layer was allowed to contain Na, and the change in the content was set as shown in FIG. 8 (c). When forming each semiconductor layer, a new Si layer is formed.
Introducing F ₄ gas and changing the fluorine content in the layer thickness direction
Like 0 (c). When forming the third i-type layer, S
The iH ₄ gas flow rate and the CH ₄ gas flow rate were changed with time as shown in FIG. In the other layers, the layers formed by the MWPCVD method change the MW power with time during formation,
In the layer formed by the RFPCVD method, the RF power was changed with time during the formation so that the distribution of the hydrogen content of each layer was as shown in FIG.

Next, a transparent electrode and a collector electrode similar to those in Example 49 were formed on the third MWp type layer.

[0549] With the above, triple type solar cell (SC Ex 61)
Has been completed.

(Comparative Example 61-1) A third i-type layer is formed.
As shown in FIG. 18 (b), the SiH_FourGas flow rate, GeH
_FourSame as Example 61 except that the gas flow rate is changed with time
A solar cell (SC ratio 61-1) was produced under the conditions.

(Comparative Example 61-2) [0551] When the i-type layer was formed, the same conditions as in Example 61 were used except that the SiH ₄ gas flow rate was 130 sccm and the CH ₄ gas flow rate was 20 sccm. A battery (SC ratio 61-2) was produced.

(Comparative Example 61-3) The first RFp type layer, the second RFp type layer, and the third RFp type layer were not formed, but the first MWp type layer and the second MWp type layer were formed. A solar cell (SC ratio 61-3) was produced under the same conditions as in Example 61 except that the layer and the layer thickness of the third MWp type layer were 20 nm.

[0553] When the same measurement as in Example 49 was performed,
The solar cell (SC Ex 61) of this example is a solar cell (SC
It was found that the characteristics were further superior to the ratios 61-1) to (SC ratio 61-3).

(Example 62) A tandem solar cell shown in Fig. 15 was produced using the deposition apparatus using the roll-to-roll method shown in Fig. 20.

In the same manner as in Example 14, the light reflecting layer and the reflection increasing layer were continuously formed on the long stainless steel sheet.

A first MWn-type layer (μc-Si layer thickness 20 nm) is formed on the substrate in the deposition chamber 901, and a first RFn-type layer (a-Si layer thickness 10 n) is further formed in the deposition chamber 902.
m), the first i-type layer (a-SiGe layer thickness 180 nm) in the deposition chamber 903, and the first RFp-type layer (a) in the deposition chamber 904.
-Si layer thickness 10 nm), first MWp in deposition chamber 905
Type layer (μc-Si layer thickness 10 nm), the second RFn type layer (μc-Si layer thickness 20 nm) in the deposition chamber 906, the second i-type layer (a-Si layer thickness 250 nm) in the deposition chamber 907,
In the deposition chamber 908, the second RF p-type layer (a-SiC layer thickness 1
0 nm), the second MWp-type layer (μc-S) in the deposition chamber 909.
The iC layer thickness of 10 nm) was sequentially formed.

Na is contained in the first i-type layer and the second i-type layer, and the change in the layer thickness direction is shown in FIG. 8 (c). SiH ₄ gas and SiF ₄ gas were used to form the semiconductor layers, and fluorine was contained in all the semiconductor layers. The raw material gas inlet of the deposition chamber 907 for forming the second i-type layer is divided into a plurality of portions, and SiH ₄ gas, CH ₄ gas, and H ₂ gas were introduced from the respective inlets. When forming the i-type layer, CH
_The change patterns of the _four gas flow rates with respect to the substrate transport direction were adjusted by the respective mass flow controllers so as to be the change pattern of the arrow 960 in FIG. By doing so, the change in the C content of the i-type layer in the layer thickness direction was as shown in FIG. 8 (c).

When the transfer of the substrate was completed, all MW power supplies, RF power supplies and target power supplies were turned off, glow discharge was stopped, and inflow of raw material gas and scavenging gas was stopped. The whole device was leaked and the wound substrate was taken out.

Next, a transparent electrode made of ITO having a layer thickness of 70 nm was continuously formed at 170 ° C. on the second MWp type layer. Subsequently, a part of this substrate is cut into a size of 50 mm × 50 mm, and a layer thickness of 5 μm and a line width of 0.5 mm are obtained by a screen printing method.
Print the carbon paste of
A silver paste having a line width of 0.5 mm was printed to form a collector electrode.

The production of a tandem solar cell (SC Ex 62) using the roll-to-roll method was completed as described above.

(Comparative Example 62-1) A solar cell (SC) was formed under the same conditions as in Example 62 except that the CH ₄ gas flow rate was kept constant in the substrate transport direction when the second i-type layer was formed. Ratio 62-1) was prepared.

(Comparative Example 62-2) The first RFp type layer and the second RFp type layer were not formed, but the first MWp type layer,
A solar cell (SC ratio 62-2) was produced under the same conditions as in Example 62 except that the second MWp type layer had a layer thickness of 20 nm.

When the same measurement as in Example 49 was carried out,
It was found that the solar cell (SC Ex 62) of the present example had better characteristics than the conventional solar cells (SC ratio 62-1) and (SC ratio 62-2).

(Example 63) A tandem solar cell manufactured by using the deposition apparatus shown in FIG. 20 was modularized and applied to a power generation system to perform a field test.

[0565] Light-irradiated 50 mm produced in Example 62
65 x 50 mm tandem solar cell (SC Ex 62)
I prepared one. EV on a 5.0 mm thick aluminum plate
An adhesive sheet made of A was placed, a nylon sheet was placed on the sheet, and 65 solar cells were arranged on the sheet, and serialization and parallelization were performed. An EVA adhesive sheet was placed thereon, a fluororesin sheet was placed thereon, and vacuum lamination was performed to form a module. The initial photoelectric conversion efficiency of the manufactured module was measured in the same manner as in Example 49. An external light that was turned on at night was used as the load, which was connected to the circuit showing the power generation system in FIG. The entire system is operated by the storage battery and the power of the module. This power generation system is called (SBS Ex 63).

(Comparative Example 63) 66 conventional tandem type solar cells (SC ratio 62-1) and (SC ratio 62-2) which were not irradiated with light were modularized in the same manner as in Example 63, and initial photoelectric conversion was performed. The efficiency was measured. This module was connected to the same power generation system as in Example 63. These power generation systems (SBS ratio 63-1), (SBS ratio 63-
2).

[0567] Each module was 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 power generation system (SBS Ex 63) using the solar cell of the present invention is the same as the conventional power generation system (SB
It was found that it has more excellent initial photoelectric conversion efficiency and field durability than the S ratio 63-1) and (SBS ratio 63-2).

Example 64 The following photovoltaic element having oxygen and nitrogen atoms in the semiconductor layer was produced.

(Example 64-1) When forming an i-type layer,
O ₂ / He gas is 100 sccm, N ₂ / He gas is 2
A solar cell (SC Ex 64-1) was produced under the same conditions as in Example 49 except that 0 sccm was introduced.

(Example 64-2) When forming the RF-i layer, ₂ sccm of O ₂ / He gas and 1 of N ₂ / He gas were used.
A solar cell (SC Ex 64-2) was produced under the same conditions as in Example 49 except that sccm was introduced.

[0572] When forming (Example 64-3) MWp-type layer, when 100sccm the O ₂ / the He gas, the N ₂ / the He gas was introduced 20 sccm, to form a RFp-type layer, O ₂
/ He gas ₂ sccm, N ₂ / He gas 1 sccm
A solar cell (SC
Example 64-3) was produced.

When the same measurement as in Example 49 was carried out,
The solar cells (SC Ex 64-1) to (SC Ex 64-3) are
It was found that the solar cell had better characteristics than the solar cell (SC Ex 49).

When the concentrations of oxygen atoms and nitrogen atoms of these fabricated solar cells were examined by SIMS, it was found that the concentrations of the introduced raw material gas (O) and the raw material gas (N) were about the same as the concentrations of the raw material gas (N) with respect to the raw material gas (Si). It was found to be contained.

As described above, it was proved that the effect of the photovoltaic element of the present invention was exhibited regardless of the element structure, element material, and element manufacturing conditions.

[0576]

[Table 1]

[0577]

[Table 2]

[0578]

[Table 3]

[0579]

[Table 4]

[0580]

[Table 5]

[0581]

[Table 6]

[0582]

[Table 7]

[0583]

[Table 8]

[0584]

[Table 9]

[0585]

[Table 10]

[0586]

[Table 11]

[0587]

[Table 12]

[0588]

INDUSTRIAL APPLICABILITY According to the present invention, photo-excited carriers are prevented from being recombined, the open-circuit voltage and the carrier range of holes are improved, and the sensitivity of short-wavelength light and long-wavelength light is improved. It becomes possible to provide a power device.

Further, the photovoltaic element of the present invention can suppress light deterioration and vibration deterioration. Further, the photovoltaic element of the present invention can suppress photodegradation and vibration degradation even when it is placed in a high temperature and high humidity environment by applying a forward bias. Further, in the photovoltaic element of the present invention, the layers are not separated even when the photovoltaic element is placed in the above environment. Furthermore, the photovoltaic element of the present invention can increase the deposition rate of the photovoltaic element,
Further, since the raw material gas utilization efficiency is high, the productivity can be dramatically improved.

Further, according to the present invention, it is possible to provide a power generation system having high field durability. .

[Brief description of drawings]

FIG. 1 is a schematic view showing a layer structure of a photovoltaic element of the present invention.

FIG. 2 is a schematic view showing a layer structure of the photovoltaic element of the present invention.

FIG. 3 is a graph showing changes in hydrogen content and alkali metal content in the layer thickness direction.

FIG. 4 is a graph showing changes in bandgap in the layer thickness direction.

FIG. 5 is a graph showing changes in B and P contents and alkali metal contents in the layer thickness direction.

FIG. 6 is a graph showing changes in Ge content and alkali metal content in the layer thickness direction.

FIG. 7 is a graph showing changes in band gap in the layer thickness direction.

FIG. 8 is a graph showing changes in carbon content and alkali metal content in the layer thickness direction.

FIG. 9 is a graph showing changes in bandgap in the layer thickness direction.

FIG. 10 is a graph showing changes in fluorine content in the layer thickness direction.

FIG. 11 is a schematic view showing an example of a deposition apparatus.

FIG. 12 is a graph showing changes over time in the power applied to the target and the bias electrode, and changes in the hydrogen and Li contents and the band gap in the layer thickness direction.

FIG. 13 is a graph showing changes in the content of the valence electron control agent in the doping layer in the layer thickness direction.

FIG. 14 is a schematic view showing a layer structure of a triple solar cell.

FIG. 15 is a schematic view showing a layer structure of a tandem solar cell.

FIG. 16 is a graph showing changes with time of B ₂ H ₆ / H ₂ and PH ₃ / H ₂ gas flow rates.

FIG. 17 is a graph showing changes over time in the SiH ₄ and GeH ₄ gas flow rates and changes in the band gap in the layer thickness direction.

FIG. 18 is a graph showing changes over time in the flow rates of SiH ₄ and CH ₄ gases and changes in the band gap in the layer thickness direction.

FIG. 19 is a block diagram showing an example of a power generation system.

FIG. 20 is a schematic view showing an example of a roll-to-roll deposition apparatus.

FIG. 21 is a schematic view showing the structure of a deposition chamber.

[Explanation of symbols]

101, 111, 121 Substrate 102, 122 MWn type layer 103, 123 RFn type layer 104, 114, 124 formed by MWPCVD method,
I-type layer containing alkali metal 105,115 RFp-type layer 106,116 MWp-type layer 107,117,127 transparent electrode 108,118,128 collector electrode 112 n-type layer 125 p-type layer 130-132 RF-i layer 400 Deposition apparatus 401 Deposition chamber 402 Vacuum gauge 403 RF power supply 404 Substrate 405 Heater 406 Waveguide 407 Conductance valve 408 Auxiliary valve 409 Leak valve 410 Bias electrode 411 Gas introduction tube 412 Applicator 413 Dielectric window 414 Sputtering power supply 415 Shutter 416 Target 417 Target shutter 418 Target electrodes 901 to 909 Deposition chamber 910 Substrate delivery chamber 911 Substrate winding chamber 912 Separation passage 913 Long substrate 914 Raw material gas inlet 915 Raw material gas Exhaust port 916 RF electrodes 917 microwave applicators 918 halogen lamp heater 919 feed inlet 920 for flowing a scavenging gas roll 920,923 guide roll 922 winding roll 931 bias electrode 930 target electrode 941 substrate peripheral portion 942 substrate central portion.

Claims (29)

[Claims] 1. A microwave plasma CVD in which a p-type layer, an i-type layer, and an n-type layer made of a non-single crystal silicon semiconductor material containing hydrogen are stacked, and the i-type layer contains an alkali metal. In the photovoltaic element formed by the method, the alkali metal and hydrogen contents of the i-type layer change smoothly in the layer thickness direction, and at least one of the p-type layer and the n-type layer is a microwave. Layer formed by plasma CVD method (MW doping layer) and RF plasma CVD
And a layer (RF doping layer) formed by a method, wherein the RF doping layer is arranged so as to be sandwiched between the MW doping layer and the i-type layer. Electromotive force element. 2. The photovoltaic element according to claim 1, wherein the i-type layer contains tin. 3. A microwave plasma CVD in which a p-type layer, an i-type layer, and an n-type layer made of a non-single-crystal silicon semiconductor material containing hydrogen are laminated, and the i-type layer contains an alkali metal. In the photovoltaic element formed by the method, the i-type layer contains at least one of germanium, tin, and carbon, and the contents of germanium and tin change smoothly in the layer thickness direction and the maximum content is Position is i
The carbon content is shifted from the center position of the i-type layer to the p-type layer, the carbon content changes smoothly in the layer thickness direction, and the position where the carbon content is minimized is offset from the center position of the i-type layer to the p-type layer i And at least one of the p-type layer and the n-type layer is a layer formed by a microwave plasma CVD method (MW.
And a layer formed by an RF plasma CVD method (RF doping layer), and the RF doping layer is disposed so as to be sandwiched between the MW doping layer and the i-type layer. Photovoltaic device characterized by the above. 4. The photovoltaic element according to claim 1, wherein the i-type layer contains both a valence electron control agent which serves as a donor and a valence electron control agent which serves as an acceptor. Power element. 5. A microwave plasma CVD method in which a p-type layer, an i-type layer, and an n-type layer made of a non-single-crystal silicon semiconductor material containing hydrogen are stacked, and the i-type layer contains an alkali metal. In the photovoltaic element formed by the method, the i-type layer is an i-type layer containing both a valence electron control agent that serves as a donor and a valence electron control agent that serves as an acceptor.
At least one of the p-type layer and the n-type layer is a layer formed by a microwave plasma CVD method (MW doping layer) and a layer formed by an RF plasma CVD method (R
F doping layer), and the RF doping layer is arranged so as to be sandwiched between the MW doping layer and the i-type layer. 6. The photovoltaic element according to claim 5, wherein the i-type layer contains tin. 7. The content of the valence electron control agent serving as the donor and the valence electron control agent serving as the acceptor change smoothly in the layer thickness direction. Photovoltaic device according to. 8. The content of the valence electron control agent serving as the donor and the valence electron control agent serving as the acceptor is maximum near at least one interface. Photovoltaic device according to. 9. The hydrogen content in the i-type layer changes smoothly in the layer thickness direction.
8. The photovoltaic element according to any one of items 8. 10. The hydrogen content of the i-type layer is maximized in the vicinity of at least one of the two interfaces of the i-type layer. 2. The photovoltaic element according to item 1. 11. The RF doping layer and / or M
The photovoltaic element according to any one of claims 1 to 10, wherein the hydrogen content is maximized near at least one of the two interfaces of the W-doped layer. 12. The RF doping layer and / or M
The photovoltaic power according to any one of claims 1 to 11, wherein the content of the valence electron control agent is maximized in the vicinity of at least one of the two interfaces of the W-doped layer. element. 13. The RF doping layer and / or M
13. The photovoltaic element according to claim 1, wherein the W doping layer contains an alkali metal. 14. The RF doping layer and / or M
The content of the alkali metal contained in the W doping layer is
The photovoltaic element according to claim 13, which has a minimum value in the vicinity of at least one interface. 15. The i-type layer, MW doping layer, RF
At least one of the doping layers contains oxygen and / or nitrogen.
14. The photovoltaic element according to any one of 14 above. 16. The i-type layer, MW doping layer, RF
The photovoltaic element according to claim 1, wherein at least one layer of the doping layers contains fluorine. 17. The photovoltaic element according to claim 16, wherein the content of fluorine is minimum near at least one interface. 18. An i-type layer (R formed by an RF plasma CVD method) between the i-type layer and the RF doping layer.
Photovoltaic device according to any one of claims 1 to 17, having a F-i layer). 19. The photovoltaic element according to claim 18, wherein the RF-i layer contains both a valence electron control agent that serves as a donor and a valence electron control agent that serves as an acceptor. 20. The content of the valence electron control agent serving as a donor and the valence electron control agent serving as an acceptor contained in the RF-i layer changes in the layer thickness direction and becomes maximum at at least one interface. 20. The photovoltaic element according to claim 19, which is characterized in that. 21. The hydrogen content of the RF-i layer is maximized in the vicinity of at least one of the two interfaces of the RF-i layer.
The photovoltaic element according to any one of 1. 22. The photovoltaic element according to claim 18, wherein the RF-i layer contains an alkali metal. 23. The photovoltaic element according to claim 22, wherein the content of the alkali metal contained in the RF-i layer is minimum near at least one interface. 24. The photovoltaic element according to claim 18, wherein the RF-i type layer contains fluorine. 25. The photovoltaic element according to claim 24, wherein the content of fluorine contained in the RF-i type layer is minimum near at least one interface. 26. The photovoltaic power generation device according to claim 18, wherein the RF-i layer is made of amorphous silicon tin (a-SiSn) containing tin. element. 27. The RF-i layer contains oxygen or / and nitrogen.
The photovoltaic element according to any one of 1. 28. The alkali metal according to claim 1, wherein the alkali metal is at least one element selected from lithium, sodium and potassium.
The photovoltaic element according to the item. 29. The photovoltaic element according to any one of claims 1 to 28, and the photovoltaic element to a storage battery and / or an external load by monitoring the voltage and / or current of the photovoltaic element. A power generation system comprising a control system for controlling the supply of electric power from the element and a storage battery for accumulating the electric power from the photovoltaic element and / or supplying the electric power to an external load. .