JPS59123279A - Manufacture of photoelectric conversion device - Google Patents

Abstract

PURPOSE:To improve the photoelectric conversion efficiency of the side of a photo irradiation light surface by a method wherein a granular mask material is selectively formed on a photo transmitting substrate, and the first electrode having a photo transmitting conductive film, non-single crystal semiconductor, and the second electrode are formed on the uneven surface formed by etching. CONSTITUTION:An insular cluster form 29 is formed on the main surface of the substrate 1. In the substrate having his mask, fibrous projections are formed by selective etching, and further the projection is made semi-shperical. The first CTF2 is formed thereon, further thereafter the non-single crystal semiconductor 4 having at least one of a P-I-N or a P-N junction, the second CTF9, and the electrode 19 are formed. Thereby, the photoelectric conversion efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a first electrode comprising a transparent conductive film on the main surface of a transparent substrate, and at least one KP junction or PN junction on the electrode. A non-single crystal semiconductor that generates photovoltaic force upon irradiation, and a second electrode (back electrode) on the semiconductor.
The present invention relates to a photoelectric conversion device (hereinafter referred to as PVO) K having the following.

The present invention provides unevenness on the main surface of the light-transmitting substrate, thereby increasing its surface area, making it long-lasting for light and short for carriers, especially holes. In addition, the purpose is to improve the light iK conversion efficiency on the light irradiation surface side.

In order to provide such unevenness, the present invention has a height difference of 300 to 4000X, preferably 800 to 2000.
0X, and the convex portion has a circular shape with an average diameter of 200 to 2oooi.

In the present invention, the total area of the convex portion/the total area of the concave portion is 0.2 to
5, preferably 0.5 to 2.

By doing this, the light-transmitting conductive film (hereinafter referred to as OTF) constituting the first electrode on the light-transmitting substrate and the semiconductor can be made to have holes for scattering the incident light on the surface. In addition, reflection at the interface between the substrate and CT 11' can be reduced. As a result, it has become possible to reduce the amount of reflected incident light to 6-8%K compared to the conventional 20-30K, which reduces the conversion efficiency by 10K.
I was able to improve my score by ~15 inches.

Furthermore, the present invention is characterized by improving the quantum efficiency of light incident on the semiconductor at short wavelengths.

That is, by increasing the optical path length for short wavelengths of 500 nm or less,
In addition, by shortening the diffusion length of one of the electron-hole pairs generated by this photoexcitation, particularly preferably the hole, the quantum The efficiency was 85% at 400nm and 500nmK compared to the conventional 60chi at 400nm and 80chi at 500nmVc.
We were able to increase this to 95%. As a result, we were able to increase the conversion efficiency by 15 to 20 inches compared to the conventional structure.
Under irradiation of 0 mW/cm), it was possible to increase the temperature up to -11.5%K.

In the present invention, a mask material is formed in the form of particles on a transparent substrate, and the substrate is etched using this as a mask to form concave portions9.As a result, the average diameter of the convex portions is 200 to 2000λ and the difference in height is small. 300-4oooi preferably 800-
It has a diameter of 2,000 mm or more and is provided in the form of a fiber.

For this purpose, the present invention involves selectively forming tin oxide into particles by a spray method, and then etching the glass substrate with hydrofluoric acid. Therefore, a major feature of the manufacturing process is that the photoetching process used in conventional integrated circuits, etc., is not used to create this uneven surface, so there is no increase in the manufacturing cost of PVO especially with this foot''L. has.

- It is known to form one layer or two layers by a vapor deposition method or a spray method. When forming this OTF by a spray method, TO (indium oxide tin oxide compound)
(3) 1500-2000λ of 1500-2000H
tin oxide (4) on the top surface.
is formed to a thickness of 200 to 600λ. Then this OT
The surface of F' can have a convex shape (11) with an average grain size of 0.2 to 0.1 μm. Therefore, a semiconductor, that is, a P-type semiconductor, e.g., S i x O,−, (O iX<'1) (5), factory semiconductor (6), N-type semiconductor (
)) Non-single crystal semiconductor with good P-N junction (4)
When forming the second electrode (8), the incident light (10) is radiated into the semiconductor like Φ・1'
3 things are possible.

It is known that as a result, the incident light 121) can be diffusely reflected in the semiconductor, so that particularly long wavelength light can be effectively used.

However, in such a conventional example, the process simply uses a convex surface made of clusters of positions by spraying, so the uneven surface has a smooth scaly shape (
When viewed under an electron microscope, it has a curved surface similar to that of a fish scale (so called scaly), and there is a need to actively utilize this shape.

In such a conventional method, the photoelectric conversion efficiency (hereinafter simply referred to as efficiency) was only up to 7% (7 to 1.9%), and the maximum was only 93 cm.

The present invention provides p6 by diffusely reflecting such long wavelength light.
In addition to increasing the quantum efficiency of long wavelength light of 00 nm or more, it also effectively uses short wavelength light, and in addition, the substrate-0TF interface,
It is characterized by further increasing the short length w''1 to 1.5 to IK by double reflecting the reflection due to the difference in refractive index at the 0TF-semiconductor interface.

In particular, short wavelength light of 300 to 500 nm has a wavelength of 200 nm in semiconductors.
Although 90 inches or more are photoelectrically converted up to 0, the holes, which are carriers on the other side, cannot reach the 40 inches or more electrode K with a flat surface electrode. In other words, optical path length (optical length OL)/carrier diffusion length (tiffusion length DL) a tiO/DI,
The photoexcited carriers live in the O/D1 where the light penetrates +'ilf term l coveler exposure (diffuses the same length to the electrode).However, according to the present invention, the O/D1. 5-7 Generally 2-・
4, so the resulting 300-50
It is now possible to improve quantum efficiency at 0 nmK.

FIG. 2 shows a vertical sectional view of A0 of the present invention. In the drawings, glass is used here as the transparent substrate (1). Further, the main surface of this substrate has a convex portion 04 and a concave portion (1 U), and the convex portion has a circular or circular surface, and the diameter thereof is 200 to 2600^ preferably 1000 to 150 mm.
0A, and the height difference between the convex and concave parts is 300~400O
A Generally it was 1000-2000^. Furthermore, the upper part of this convex part was made to have a hemispherical shape to prevent abnormal growth of the coating at the end of this convex part. Furthermore, OT on this uneven surface
F (2) has a thickness of 1500 to 200 OA, and its surface is mainly composed of tin oxide.

Furthermore, this OTF K is closely attached to a P-type non-single-crystal semiconductor obtained by plasma OVD, for example, S with a thickness of about 100λ.
i x O,-,, <O<X<'1 e.g. x = 0
．． 8)' (5), and the upper surface is covered with 10 to 1 boron.
For example, an amorphous or semi-amorphous silicon semiconductor doped with hydrogen or a halogen element made by a glow discharge method is
a non-monocrystalline semiconductor (4) having one P-N junction, such as an N-type polycrystalline or microcrystalline silicon semiconductor (7) having a thickness of O11μ and further having a thickness of approximately 100λ; , and then a second 0TF (
9) For example, TO is formed to have an average thickness of 900 to 1300 λ, preferably 1050 λ, and the reflective electrode U on the upper surface thereof is provided with aluminum or silver as a main component.

The characteristics obtained in this structure are compared with the conventional structure shown in FIG. 1 as follows.

Conventional example Invention open circuit voltage (V) 0.84 0.92 Short circuit current (mA/cm) 15°3 19°8 Fill factor (%) 61°7 ~6 days, Q conversion efficiency (%)
7゜9312゜O'7 The above efficiency has an area of 1゜05 cm
AM 1 (100
This is the characteristic when irradiated with irradiation light of mW/cm).

In view of this, the present invention has the great feature of being able to improve efficiency by 50% compared to the conventional method.

FIG. 3 is a summary showing the effects of the present invention.

In the drawing, the convex part α → and the concave part α turn O of the glass substrate (1)
T F (2), P layer (5), 1 layer (6), N layer (7)
Semiconductor with good P-N junction (4) Back electrode (8
).

In the drawing, the incident light (No. 93 or more light enters into the glass, ie, reflection can be effected only at the air-glass interface.

Furthermore, since the incident light (1A) has - reflection at the glass-0TF interface, this remains as reflected light.In any case, it is clear that the reflectance can be extremely reduced compared to the conventional example.

I get into it.

In addition, in a semiconductor, a hole (1'I) to an electron α generated by photoexcitation is located at the center (t) of the recess a4.
(the most stable for electrons -t 4itf
L-'V) to the second electrode (8)K. Since the diffusion length of electrons is 1000 times longer than that of holes, one layer (6) is 0.
．． Even if it is 3 to 0°8μ, for example 0.5μ, there is no problem with the drift.

On the other hand, holes, which are only about 1/1000 of electrons, have a drift distance (b) that is very close to the OTF, and as a result, they are prevented from being captured by the recombination center and annihilated. For this reason, it can be seen that the present invention, in which oL/DL21 is particularly set to 2 to 10, is extremely important.

Furthermore, the uneven surface of this substrate is the surface of the semiconductor (4) made by plasma OVD or LPOVD (semiconductor (7)
) - electrode (8) interface) to induce unevenness, and since this uneven surface has a height difference of 200 to 2000X, the reflected light (c) of long wavelength light α on the back surface also lengthens its optical path. can do. Therefore, it can be done at the back electrode interface. Especially for long wavelength light of 600nm or more) for a long time (
(Long optical path) It was possible to confine it in a semiconductor, and it was possible to promote improvement of quantum efficiency in the long wavelength region.

If no metal is used as the main surface and only 0TIII' is used, long-wavelength light can be emitted to the back surface, and another important application is to use a solar heat utilization device above the back surface.

Regarding this long wavelength light, it is natural that the reflection efficiency can be further improved by using the back electrode as an OTF and a reflecting electrode as shown in FIG.

FIG. 4 shows the manufacturing process for making the PVA of the present invention.

Figure (4) shows the process in the drawing.
mm was used. Tin chloride was formed into islands on the upper surface by a spray method. This tin chloride has a concentration of 450 to 600 in the air.
It was baked at 500°C for 30 minutes to 2 hours. Then, this stannide metamorphoses into stable tin oxide and forms the substrate (1).
Island-like clusters (c) were formed on the main surface. This cluster has a diameter of 200 to 0.5μ, some of which may be continuous islands.

In this way, a tin oxide mask was made.

Which mask is made with silane and ammonia (Z') '700
It is also effective to form silicon nitride into islands by a vapor phase method at a temperature of ~800°C. This gas phase method is performed at atmospheric pressure and can create a cluster structure.

Regarding this mask material, it is also effective to produce only silane by a vapor phase method and form silicon into islands. In this way, an island-shaped mask (c) was formed of tin oxide, silicon nitride, or silicon.

Thereafter, the substrate with this mask was immersed in hydrofluoric acid. By selectively etching the immersed glass, it was possible to form fibrous convex portions. Thus, by controlling the etching time to 5 to 25 minutes, the difference in height of the uneven portion can be reduced to 300 to 400 OA, for example, 20 OA.
It was set to 00i. Furthermore, after this, apply the mask material to O'F++02.
The glass was then etched lightly with hydrofluoric acid diluted to 1/10 with water to make the ends of the protrusions curved and hemispherical.

Furthermore, as shown in FIG. 4 φ) on this upper surface, the first OT
F(2) was formed using an electron beam evaporation method or a plasma vapor phase method. For example, in the plasma vapor phase method, indium chloride and tin chloride are mutually introduced into a reactor together with an oxide gas, and a plasma reaction of 13° 56 MHz results in 0.0
Performed at a pressure of 5 to 1 tOrr, 1000 to 2000
It was formed to a film thickness of ＾. Furthermore, this formed film was heated in vacuum for 30 minutes.
Heat at 0 to 500°C, and then
OT whose main component is tin oxide with a thickness of 200~500^
F was formed by a reduced pressure gas phase method.

To form this OTF, OF, SnO~ containing Br, is heated at 450 to 600°0, for example, 500°, together with an oxide gas.
It may be formed to a thickness of 1000 to 2500^ at 0 and 1 to 3 t o r r.Furthermore, as shown in Fig. 4 (0), silane and methane are formed by a plasma vapor phase method. Yop F31xO, -i (
o<x<x). Sara K B7H, 0.5~
IPPM is added and silane is removed by public money/kuplasma vapor phase method.
．． It is formed to have a thickness of 4 to 0.8 microns, for example 0.5 microns. At this time, it had a curved line, and the difference in height was nearly 1 oooi. Furthermore, the KN type semiconductor is PFvB i H,='1
%.

5IVH210 by plasma vapor phase method.

Thereafter, a second 0TF (9) was formed using a known electron beam evaporation method to have a thickness of 900-1300^, for example, 1o5oi on average. Furthermore, an electrode (one of which was formed by a vacuum evaporation method and an OVD method) mainly composed of aluminum for reflection was formed.

In this manner, the structure shown in FIG. 4(0) was obtained.

The characteristics obtained in FIG. 4 (0) are shown in correspondence with FIG. By selectively etching the substrate using a substrate, it was possible to have an uneven surface on the side of the incident light surface. It is also effective as a tandem structure with an N junction.

Further, the semiconductor was made into a valve single-crystal body made of silicon as a main component by plasma vapor phase method. However, 5iXGe+-((0
<X < 1) S i X S nH-x (0 <
X <'l) S 1jN4-x (3doX<, 4)
You can also use it as

As is clear from the above description, the present invention uses a glass plate with a thickness of 0.5 to 3 mm as a transparent substrate. However, it is also effective to use flexible glass (quartz) with a thickness of 1 to 10 microns as the substrate. Furthermore, this substrate may be made of a transparent organic resin such as polyimide or polyamide.

[Brief explanation of drawings]

FIG. 1 shows a vertical sectional view of a conventional photoelectric conversion device. FIG. 2 shows a photoelectric conversion device of the present invention. FIG. 3 shows another photoelectric conversion device of the present invention. Figure 4 shows the method for manufacturing the photoelectric conversion device of the present invention *Figure 1

Claims (1)

[Scope of Claims] 1. A step of selectively forming a granular mask material on a light-transmitting substrate, a step of selectively etching the substrate to form an uneven surface, and a step of forming a light-transmitting mask material on the uneven surface. a step of forming a first electrode having a conductive film; a step of forming a non-single crystal semiconductor having at least one PiN or PN junction; and a step of forming a second electrode on the semiconductor. A photoelectric conversion device 1 and a method for manufacturing the device. 2. Patent;:l'j In the first item, a tin compound is formed by a spray method on a transparent substrate mainly composed of glass, and the tin oxide is masked by heating and baking in an oxidizing atmosphere. 1. A method for manufacturing a photoelectric conversion device, comprising the steps of: forming a material; and selectively etching the substrate with an oxygen liquid to form four parts.