JPH10275922A - Optoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and efficient optoelectric conversion device. SOLUTION: In an optoelectric conversion device P1, a crystal oxide layer 2 containing at least one type of aluminum, magnesium, and calcium and a silicon semiconductor layer S1 consisting of a plurality of layers with a pn junction are sequentially laminated on the other main surface of a translucent substrate 1 where one main surface forms a light reception surface, and at the same time output is led from the p and n layers of the silicon semiconductor layer S1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion device such as a thin-film polycrystalline silicon solar cell and an optical sensor.

[0002]

2. Description of the Related Art Conventionally, a crystalline silicon solar cell using a crystalline silicon wafer has been put into practical use in the field of a solar cell which is one of photoelectric conversion devices, but it is necessary to use a large amount of crystalline silicon wafer. Therefore, there is a problem of shortage of raw materials and a problem of raw material cost. Development and commercialization of low-cost and high-efficiency thin-film polycrystalline silicon solar cells using thin-film polycrystalline silicon that can solve these problems are expected. I have.

In general, the first requirement for manufacturing a thin film solar cell at low cost is that the substrate to be used is low in cost. Substrates meeting this requirement include glass substrates and SUS substrates, and have already been put to practical use in amorphous silicon solar cells characterized by a low-temperature process. Also in a thin-film polycrystalline silicon solar cell, it is desired that a low-cost substrate such as a glass substrate or a SUS substrate can be used by setting the device process at a relatively low temperature.

As an example of research conducted in this direction, in Japan, p-C is deposited on a thin film polycrystalline silicon underlayer formed on a glass substrate by a laser annealing method.
Method 1 for forming a thin film polycrystalline silicon photoactive layer by VD method (Proc. 1st. WCPEC (1994) 1575-1578;
3957, see JP-A-7-94766).
-Amorphous silicon formed by CVD
(Solid-phase crystallization) method 2 (Pro
c.1st.WCPEC (1994) 1315-1318, JP-A-2-28315, JP-A
6-204539, JP-A-7-135332 and JP-A-7-335660).

[0005] Outside Japan, a method of growing a thin-film polycrystalline silicon from a liquid phase on a glass substrate using the LPE method 3 (Proc. 1st. WCPEC (1994) 1579-1582, So
lid State Phenomena 37-38 (1994) 459-464, Journal of
Material Science: Materials in Electronics .5 (199
4) 305-309, J. Electrochem. Soc. Vol. 140, No. 11 (1993)
3290-3293).

Next, a second requirement for manufacturing a thin-film solar cell at low cost is that the conversion efficiency of the device is higher. This is because the higher the conversion efficiency, the lower the manufacturing cost per watt. As one of the measures for improving the conversion efficiency, there is a method of minimizing the reflection loss light by reducing the area of the metal electrode existing on the light incident surface side as much as possible. In this regard, in a device using a single crystal or polycrystalline silicon substrate, the light incident side metal electrode is used as a fine pattern to reduce the area of the metal electrode, reduce the amount of light reflected on the metal surface, and increase the amount of incident light. Attempts have been made to introduce GaN into crystalline silicon (see the 3rd High Efficiency Solar Cell Workshop (Toyama, 1992) 28). Also, research has been conducted on an element structure in which a high-quality substrate is used, and a pn junction, a positive electrode, and a negative electrode are arranged on the opposite side of the light incident surface to eliminate light reflection loss due to a metal electrode. (RASinton et al, Electron Device Letters, vo
l.EDL-7 (1986) 567, RRKinget al, 20th IEEE Photovo
ltaic Specialists Conf., Las Vegas (1988) 538). On the other hand, an amorphous silicon solar cell uses a transparent conductive film and has a structure in which a metal electrode with high reflectivity does not need to be arranged on the light incident side, so that at least incident light is prevented from being blocked by the metal electrode. is made of.

Further, as one of the other measures for increasing the efficiency, a method of reducing the reflectance of incident light on a surface other than the electrode portion is being studied. In this method, a method of reducing the surface reflectance by forming an antireflection film such as a silicon nitride film or a silicon oxide film has been more widely implemented than in the past. Research on a light trapping structure (light confinement structure) that can be performed and that can reduce the probability that light once entering the inside of the silicon is separated from the silicon surface again has been promoted. A typical example of this light trapping structure is a texture structure formed by utilizing the fact that the etching rate differs depending on the crystal plane orientation when wet etching silicon with a specific liquid (J. Haynos et al, Int.
Conferenceon Photovoltaic Power Generation (Hambur
g, 1974) 487) and RI, a dry etching technology
Random and fine surface structures formed using the E method (K. Fukui et al, Technical Digest of the Internati
onal PVSEC-9 (1996) 93-96 and 109-110).

As described above, in order to be able to manufacture a thin-film polycrystalline silicon solar cell at low cost, it is desirable to be able to use an inexpensive substrate such as a glass substrate. In order to further increase the conversion efficiency, it is desirable that the area of the metal electrode on the light incident side is as small as possible, and it is even more desirable if the arrangement of the metal electrode on the light incident side can be avoided. It is also desirable that a light trapping structure can be introduced.

[0009]

Problems to be solved by the above-mentioned method when manufacturing a thin film polycrystalline silicon solar cell by using a low cost material and increasing the efficiency are as follows.

In the method 1, a glass substrate is used to reduce the cost of the material, but the large area recrystallization rate in the laser annealing method used for forming a thin polycrystalline silicon layer thereon is slow. Therefore, it is not suitable for mass production at low cost. Further, the crystal grain size of the recrystallized crystal cannot be sufficiently increased to a maximum of about 1 μm, and the existence of crystal grain boundaries increases. Therefore, the influence of recombination there increases, and this is not suitable for high efficiency. Furthermore, in the formation of the photoactive layer by the p-CVD method, it takes several hours to make the film quality sufficient for the quality of the photoactive layer level, which is not suitable for cost reduction. In addition, although an ITO film, which is a transparent conductive film, is used as an electrode layer on the light incident surface side, some metal electrode terminals are formed in the extraction electrode portion, and light incident on this portion is reflected. There is a problem of loss. In addition, since an extraction portion of the element rear surface side electrode is also formed on the light incident surface side, there is a problem that incident light corresponding to the area of this portion cannot be used. In addition, since the metal electrode is not formed on the back surface of the solar cell element, a considerable amount of the light that reaches the back surface of the element is transmitted as it is, and there is a problem that the utilization efficiency of incident light is low.

[0011] In the method 2, a low cost material is achieved by using a SUS substrate. However, it takes several hours to form an amorphous silicon layer to which the SPC method is applied, and about ten hours to solid phase crystallization. In short, there is a problem in low-cost mass production. In addition, since the recrystallized crystal grain size is about 1 μm at the maximum and cannot be made sufficiently large, and the existence of crystal grain boundaries increases, the amount of recombination there increases, which is not suitable for high efficiency.

Although an ITO film, which is a transparent conductive film, is used as the electrode layer on the light incident surface side, some metal electrode terminals are formed in the extraction electrode portion.
There is a problem that the light incident on this portion is reflected and lost.

In method 3, the cost is reduced by using a glass substrate. However, in the current LPE method, there is a difficulty in developing a device suitable for a solar cell class large-area element, and the film forming speed is not sufficient. Therefore, there is a problem in mass production at low cost.
In addition, since the film quality has not been sufficient, no report on element fabrication research has been made at this time.
There is no known research example regarding the method of forming the back electrode.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a low-cost and high-efficiency photoelectric conversion device.

[0015]

In order to achieve the above-mentioned object, a photoelectric conversion device according to the present invention comprises an aluminum, magnesium, aluminum, magnesium,
And a crystal oxide layer containing at least one of calcium and calcium, and a silicon semiconductor layer composed of a plurality of layers having a pn junction are sequentially laminated, and an output is derived from the p layer and the n layer of the silicon semiconductor layer. It is characterized by the following.

Thus, a glass substrate as a low-cost material can be used by performing a relatively low-temperature element process.

That is, at least one of aluminum, magnesium and calcium is formed on a glass substrate.
A thin-film polycrystalline silicon solar cell comprising a seed-containing crystalline oxide layer formed thereon and a plurality of polycrystalline silicon thin-film layers formed thereon with respect to impurity concentration, comprising a pn junction, a positive electrode, and a negative electrode. Electrodes are formed on the thin-film polycrystalline silicon layers, respectively, and incident light is taken in from the glass surface side. by this,
Light reflection loss due to the metal electrode on the light incident side can be eliminated, and the utilization efficiency of incident light can be increased.

Further, the lower layer in contact with the crystal oxide layer of the silicon semiconductor layer is in a polycrystalline state, and has an average grain size of 3 μm or more in a direction parallel to the other main surface of the light transmitting substrate. I do. The lower layer in contact with the crystal oxide layer of the silicon semiconductor layer is in a polycrystalline state, and its crystal orientation is mainly <111> oriented in a direction perpendicular to the other main surface of the light-transmitting substrate. It is characterized by the following.

That is, taking advantage of the fact that crystal growth is carried out through a liquid phase, at least the crystalline silicon grains in the lower layer in contact with the crystalline oxide layer among the plurality of silicon semiconductor layers have a grain size of the substrate. The average particle size is 3 μm or more with respect to the horizontal direction (substrate surface direction). Particularly preferably, those having a relatively large grain size of about 10 μm or more mainly exist, and the crystal orientation is mainly oriented in the <111> orientation with respect to the direction perpendicular to the substrate. . Thereby, high efficiency can be obtained especially in a thin-film polycrystalline silicon solar cell.

It is desirable that the carrier lifetime in the thin-film polycrystalline silicon is at least about 0.1 μsec or more, and more preferably about 1 μsec or more. Although it depends on the degree of passivation in the field, it is preferably about 10 to 30 μm or more (see Kojiya et al .: The 5th High Efficiency Solar Cell Workshop (1995) Nagano pp. 19-22). The thin-film polycrystalline silicon of the present invention satisfies these conditions and is suitable for high efficiency. In addition, since the crystal orientation is mainly oriented in the <111> direction with respect to the direction perpendicular to the substrate, even if the crystalline silicon is polycrystalline, the surface can be made almost flat, and When a random and fine uneven structure is formed on the surface of the crystalline silicon layer, the structure can be formed almost uniformly and easily over the entire substrate.

Further, a lower layer of the silicon semiconductor layer which is in contact with the crystal oxide layer is in a polycrystalline state and has a doping impurity concentration of 10 ¹⁶ to 10 ²² / cm ³ . If the lower limit of the doping impurity concentration is exceeded, recombination on the light incident surface side of the device becomes large, resulting in deterioration of characteristics such as reduction of open-circuit voltage in solar cell characteristics.

The photoelectric conversion device according to the present invention is characterized in that the total thickness of the plurality of polycrystalline silicon layers is 1 to 50 μm. If the thickness of the polycrystalline silicon layer is too thin, the incident light cannot be used sufficiently, so that the short-circuit current decreases.On the other hand, if the thickness is too thick, the dark current generally increases, depending on the film quality, and the open-circuit voltage decreases. In addition, since the moving distance of the photo-generated carriers due to the diffusion to the electrode becomes longer, the probability of recombination during the diffusion movement increases, which may adversely affect the short-circuit current.

The layer of the silicon semiconductor layer which is in contact with the positive electrode or the negative electrode is rough and has a reflectance of 400 to 400 nm.
It is characterized by being 5% or less with respect to light of 1000 nm. That is, the contact surface of the thin-film polycrystalline silicon layer in contact with the positive and negative electrodes in the semiconductor layer has a random and fine uneven structure, and the reflectance when the contact surface is the surface has a wavelength of 400 to 1000 nm. 5% or less of the light. In the case of a solar cell, it is important to introduce a light trapping structure in order to improve the characteristics, but in the present invention, the surface of the thin-film polycrystalline silicon layer in contact with the electrode is dry-etched by RIE, With a fine and random irregular structure, the effect of light scattering on the back of the device is enhanced to achieve a favorable light trapping structure with excellent solar cell efficiency, making it much more efficient than conventional thin film devices It is possible to manufacture a simple solar cell.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG.
In the photoelectric conversion device P1 of the present invention, aluminum, magnesium, and calcium are formed on the other main surface 1b of the glass substrate 1, which is one of the light-transmitting substrates whose one main surface 1a forms a light receiving surface for receiving incident light. Among them, a crystal oxide layer 2 containing at least one kind and a silicon semiconductor layer S1 composed of a plurality of layers having a pn junction are sequentially laminated, and an output is derived from the p layer and the n layer of the silicon semiconductor layer S1. In addition, a positive electrode and a negative electrode are provided side by side.

As the glass substrate 1, a 7059 substrate and a 1737 substrate manufactured by Corning Incorporated, and a soda glass substrate most commonly commercialized by each glass manufacturer are used. The following description is based on an example using a 7059 substrate, except that a difference due to a glass substrate poses a problem, but the present invention is not limited to this. Further, an example in which aluminum oxide is used as the crystal oxide layer will be described.

First, an aluminum oxide layer 2 which is a crystalline oxide layer is formed on a glass substrate 1 by 10 nm to 5000 nm.
It is formed with a film thickness of about. In forming this layer, a known vacuum film forming technique such as an evaporation method, a CVD method, and a sputtering method can be used.

Next, a first silicon layer 3, which is a thin film polycrystal, is formed on the aluminum oxide layer 2 to a thickness of about 0.1 to 5 μm. However, when the second silicon layer 4 described later is not formed, the first silicon layer
The thickness is about 50 μm. In forming the first thin-film polycrystalline silicon layer, crystal growth is performed at a relatively low temperature via a liquid phase, and relatively large crystal grains are grown.

That is, a liquid phase is formed at a relatively low temperature by the eutectic phenomenon of Si and a metal element forming a eutectic system with Si, and crystal growth through the liquid phase is utilized. To grow a crystal having a relatively large grain size.

At this time, as a method of supplying and reacting the Si and the eutectic metal, a method of supplying a mixture of Si and the eutectic metal powder onto the glass substrate 1 and performing a heat treatment, or a method of vaporizing the eutectic metal and Si are used. There is a method of simultaneously forming a film in a phase state or forming a Si layer after forming a eutectic metal layer and performing a heat treatment during or after the film formation. Here, as a metal element forming a eutectic system with Si, aluminum (Al), tin (Sn), indium (In), antimony (Sb),
There are bismuth (Bi), gallium (Ga), and the like, and mixtures thereof.

The formation of the liquid phase is realized by setting the temperature to be equal to or higher than the eutectic temperature of Si and the eutectic metal element. For example, in a system composed of Si and Al, heat treatment is performed at a temperature of 577 ° C. or higher, which is the eutectic temperature of Si and Al. The atmosphere may be an inert gas atmosphere such as an argon (Ar) gas or a nitrogen (N ₂ ) gas, or a gas atmosphere in which a reducing hydrogen (H ₂ ) gas and an inert gas are mixed at an appropriate ratio. I do.
The pressure is preferably a reduced pressure condition such as a vacuum, but may be a normal pressure. The heat treatment time is about 5 minutes to 60 minutes, excluding the time for raising and lowering the temperature.

In particular, when a metal containing Al is used as a eutectic metal, Al can be used as a doping element. Therefore, in forming an element, the first silicon layer 3 is required to function as a p ++ layer. Can be. p +
The presence of the + layer has a function of forming a built-in electric field on the light incident surface side of the second silicon layer 4 to be described later and reducing recombination of photogenerated carriers on the light incident surface side, and thus is suitable for high efficiency. It becomes something. At this time, the doping impurity concentration in the first silicon layer 3 (the lower layer of the silicon semiconductor layer S) is preferably about 10 ¹⁸ to 10 ²² / cm ³ , but the doping impurity concentration is 10 ¹⁶ to 10 ¹⁸ When the density is about / cm ³ , the effect described above is reduced, but does not hinder the use as a solar cell. The crystal grain size obtained at this time is mainly a crystal grain having an average grain size of 3 μm or more in a direction parallel to the substrate (substrate surface direction) and a relatively large grain size of about 10 μm or more. Was. This reduces the abundance of the crystal grain boundaries and reduces carrier recombination at the crystal grain boundaries, which is more suitable for increasing the efficiency of the solar cell.
Further, the aluminum oxide layer 2 is suitable as a base layer for growing polycrystalline silicon, and also has a function of preventing the above-mentioned liquid phase from reacting with the glass substrate. Further, the presence of the aluminum oxide layer 2 can give the crystal orientation of the polycrystalline silicon layer an orientation. In the present invention, the thin-film polycrystalline silicon grown on the aluminum oxide layer 2 is mainly <
111> The orientation is selected.

Next, the second silicon layer 4, which is a thin-film polycrystal, is combined with the first silicon layer 3 on the first silicon layer 3 by using a vacuum film forming technique such as a CVD method or a sputtering method. To a total film thickness of 1 to 50 μm. Here, the doping concentration of the second silicon layer 4 is about 10 < ¹⁴ > to 3 * 10 < ¹⁸ > / c so as to suitably function as a photoactive layer.
and m ^3. As a method of forming the second silicon layer 4 at a relatively high speed at a relatively low temperature, there is a cat-CVD method. Further, the second silicon layer 4 is formed of the first silicon layer 3
May be formed by the above-described method used in forming the. However, the eutectic metal used is mainly Sn or I
n and other elements that are not originally involved in doping.
l (p-type doping element) and Sb (n-type doping element) are adjusted and introduced by a necessary amount so as not to deviate from the above-mentioned doping concentration condition and to improve the quality as a photoactive layer. Try not to lose. When the second silicon layer 4 is not formed, the thickness of the first silicon layer 3 is set to 1 to 50 μm, and the doping impurity concentration is set to about 10 ^{16 to} 3 × 10 ¹⁸ / cm ³ .

Next, the front surface of the second silicon layer 4 (on the back side as an element) is subjected to RIE (Reactive I
A random and fine concavo-convex structure is formed by using a dry etching technique by an on-etching method.

The surface structure obtained by the RIE method provides an excellent light trapping effect, and is very effective particularly when there is a demand for increasing the efficiency of using incident light in a thin film state such as a thin film polycrystalline silicon solar cell. is there.

Here, the formation of the random and fine concavo-convex structure by the RIE method is performed on the surface of the first silicon layer 3 when the first silicon layer 3 is formed. Is also good. In that case, the second silicon layer 3 described above is laminated according to the random and fine uneven structure formed on the surface of the first silicon layer 3,
A light trapping structure similar to the case where the RIE method is applied to the surface of the second silicon layer 4 can be formed. Of course, a random and fine uneven structure may be formed on both the surface of the first silicon layer 3 and the surface of the second silicon layer 4 by the RIE method.

As described above, the layer in contact with the positive electrode or the negative electrode, which will be described later, of the silicon semiconductor layer 7 has a rough surface, and the reflectance thereof is 5% or less with respect to light having a wavelength of 400 to 1000 nm. A solar cell can be realized.

Next, the second silicon layer 4 which is a photoactive layer
A third silicon layer 5 having a conductivity type opposite to the conductivity type of the second silicon layer 4 is formed in a predetermined upper region to form a pn junction. Regarding the formation of the third silicon layer 5,
A known vacuum thin film forming technique such as a CVD method and a sputtering method can be used. Here, the third silicon layer 5 may be a crystalline silicon film or an amorphous silicon film. 100 to 2 in the case of a crystalline silicon film
It is formed to a thickness of about 000 nm, and in the case of an amorphous silicon film, to a thickness of about 5 to 1000 nm. In the latter case, a so-called heterojunction is formed. However, when an intrinsic type amorphous silicon layer is inserted between the second silicon layer 4 and the third silicon layer (amorphous silicon layer) 5 with a thickness of 2 to 40 nm, the characteristics are improved. Is more suitable.

Next, the second silicon layer 4 which is a photoactive layer
A fourth silicon layer 6 having the same conductivity type as that of the second silicon layer 4 and a higher doping concentration is formed in a specific region different from the region where the third silicon layer 5 is formed. Film. The fourth silicon layer 6 is formed by CVD
A known vacuum thin film forming technique such as a sputtering method or a sputtering method can be used. Here, the fourth silicon layer 6 may be a crystalline silicon film or an amorphous silicon film. 100-2000 for a crystalline silicon film
In the case of an amorphous silicon film, it is formed with a thickness of about 5 to 1000 nm. In the latter case, a so-called heterojunction is formed, but the second silicon layer 4 and the fourth silicon layer (amorphous silicon layer) 6
In between, an intrinsic type amorphous silicon layer having a thickness of 2 to 4
Inserting at 0 nm is more suitable for improving characteristics. In addition,
Even if the fourth silicon layer 6 is not formed, it does not prevent formation of an element having a pn junction.

Next, the first and second metal electrodes 7 and 8 serving as the first and second extraction electrodes are formed on the third and fourth silicon layers 5 and 6 by vacuum film forming technology and printing. Then, a known technique such as a sintering technique and a plating technique is combined to form a thin-film polycrystalline silicon solar cell.

Here, in order to take out photogenerated carriers more effectively, the third and fourth silicon layers 5 and 5 shown in FIG.
6 may be made narrower, and the arrangement of the third and fourth silicon layers 25 and 26 may be made finer as in the photoelectric conversion device P2 shown in FIG. 2A is a top view of FIG. 3A and FIG. 3B is a perspective view of FIG.
In FIG. 2, reference numeral 27 denotes a first comb-shaped metal electrode;
This is a comb-shaped second metal electrode having a polarity different from that of the metal electrode.
The silicon semiconductor layer S2 includes a first silicon layer 3, a second silicon layer 4, a third silicon layer 25, and a fourth silicon layer 26. In addition, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1 and the description thereof is omitted.

In the case where the arrangement of the third and fourth silicon layers has a limit in miniaturization or the quality of the second silicon layer 4 has a limit in improving the efficiency alone, it is not possible to achieve high efficiency. Is to make the region where the third silicon layer 35 is formed sufficiently larger than the region where the fourth silicon layer 36 is formed, as in the photoelectric conversion device P3 shown in FIG. What is necessary is just to make the 1st silicon layer 3 and the 4th silicon layer 36 contact directly. FIG.
In the above, 37 is a first metal electrode, and 38 is a second metal electrode having a different polarity from the first metal electrode. Silicon semiconductor layer S3
Is composed of a first silicon layer 3, a second silicon layer 4, a third silicon layer 35, and a fourth silicon layer 36. Other configurations similar to those in FIG.
The same reference numerals are given and the description is omitted.

Even when the fourth silicon layer is not formed, there is a limit in miniaturization of the arrangement of the third silicon layer and the second extraction electrode and a limit in improving the quality of the second silicon layer. In the case where high efficiency cannot be achieved by using only these, the region where the third silicon layer 45 is formed, as in the photoelectric conversion device P4 shown in FIG.
The third silicon layer 45 is set to be sufficiently wider than the area where the third silicon layer 45 is not formed, and the second metal electrode 48 serving as the second extraction electrode is brought into direct contact with the first silicon layer 3. I just need. In FIG. 5, reference numeral 47 denotes a first metal electrode, and 48 denotes a second metal electrode having a polarity different from that of the first metal electrode. The silicon semiconductor layer S4 includes a first silicon layer 3, a second silicon layer 4, and a third silicon layer 45. In addition, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1 and the description thereof is omitted.

As described above, it is possible to provide a photoelectric conversion device which is very suitable for a low-cost and high-efficiency thin-film polycrystalline silicon solar cell using a glass substrate.

[0044]

As described above in detail, according to the photoelectric conversion device of the present invention, since both the positive electrode and the negative electrode are arranged on the surface opposite to the light receiving surface, the metal electrode of the incident light Surface reflection caused by the light can be completely eliminated, and a photoelectric conversion device suitable for a high-efficiency solar cell or the like and having extremely high use efficiency of incident light can be obtained.

In addition, since the structure is such that a crystalline silicon layer is formed on a substrate via a crystalline oxide layer, crystalline silicon is formed by a crystal growth method via a liquid phase while preventing a reaction with the substrate. be able to. For this reason, an inexpensive glass substrate can be used as the substrate, and the crystal growth method via the liquid phase facilitates a sufficient enlargement of the silicon crystal grain size. The crystal orientation of the crystalline silicon layer grown thereon can be selectively oriented to a specific orientation.

Further, by setting the impurity doping concentration of the crystalline silicon layer in contact with the crystalline oxide layer to a specific range, a function suitable for increasing the efficiency of a photoelectric conversion device such as a solar cell can be provided.

Further, by introducing an excellent light trapping structure by the RIE method, the utilization efficiency of incident light can be increased, and a highly efficient photoelectric conversion device can be formed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a photoelectric conversion device according to the present invention.

FIG. 2 is a cross-sectional view illustrating another photoelectric conversion device according to the present invention.

3A and 3B are views for explaining another photoelectric conversion device according to the present invention, wherein FIG. 3A is a top view and FIG.

FIG. 4 is a cross-sectional view illustrating another photoelectric conversion device according to the present invention.

FIG. 5 is a cross-sectional view illustrating another photoelectric conversion device according to the present invention.

[Explanation of symbols]

 1: glass substrate (translucent substrate) 2: aluminum oxide layer (crystal oxide layer) 3: first silicon layer 4: second silicon layer 5, 25, 35, 45: third silicon layer 6, 26, 36: fourth silicon layer S1 to S4: silicon semiconductor layer P1 to P4: photoelectric conversion device

Claims (5)

[Claims] 1. A light-transmitting substrate having one main surface serving as a light-receiving surface, a crystal oxide layer containing at least one of aluminum, magnesium, and calcium, and a plurality of layers having a pn junction on another main surface of the light-transmitting substrate. A photoelectric conversion device, wherein a silicon semiconductor layer is sequentially laminated and an output is derived from a p-layer and an n-layer of the silicon semiconductor layer. 2. The photoelectric conversion device according to claim 1, wherein the lower layer of the silicon semiconductor layer is in a polycrystalline state, and has an average particle size of 3 μm or more in a main surface direction of the translucent substrate. Conversion device. 3. The method according to claim 1, wherein the lower layer of the silicon semiconductor layer is in a polycrystalline state, and its crystal orientation is selectively oriented mainly in the <111> direction in a direction perpendicular to the main surface of the translucent substrate. The photoelectric conversion device according to claim 1. 4. A method according to claim 1, wherein the lower layer of the silicon semiconductor layer is in a polycrystalline state and has a doping impurity concentration of 10 ^{16 or} less.
2. The photoelectric conversion device according to claim 1, wherein the value is 10 ²² / cm ³ . 5. The silicon semiconductor layer in contact with the positive electrode or the negative electrode has a rough surface, and has a reflectance of 400 to 1 in wavelength.
The photoelectric conversion device according to claim 1, wherein the ratio is 5% or less with respect to light of 000 nm.