JPS5818972A - Photoelectric converting device - Google Patents

Abstract

PURPOSE:To reduce the surface reflection factor in a wide wavelength region by a method wherein a reflection preventing film of metal oxide, having titanium oxide as a main ingredient, smoothed irregularities and the thickness of 600- 1,000A, is provided on the light-irradiating surface of a photoelectromotive force generating substrate, and an irregular reflection is generated in the film. CONSTITUTION:A PSG film containing high density of p is deposited on a p type substrate 1 consisting of single crystal or polycristalline semiconductor, and an n<+> type layer 2 is formed by diffusing said p in the substrate 1 by performing a heat treatment. Then, a comb type electrode 7 and an external lead-out electrode 6 are formed by performing a screen printing on the surface of the layer 2 using the paste such as Ag, Al, Ni and the like, and a reflection-preventing film 3 of 600-1,000A in thickness is deposited on the whole surface including said electrodes 6 and 7 by performing a screen printing using the ink having Ti oxide. The size of meshes and the viscosity of the ink used for the above screen printing are to be properly selected, and a number of concavities 15 and convexities 14 are formed on the surface of the film 3. Subsequently, a back side electrode 4 is deposited on the back side of the substrate 1 using similar material.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a metal oxide anti-reflection film having smooth irregularities on the light irradiation surface of a semiconductor that generates photovoltaic force, thereby causing incident light to be diffusely reflected within this anti-reflection film. In particular, it is intended to further reduce reflection on the light irradiation surface and, in turn, completely improve the conversion efficiency of the photoelectric conversion device.

This invention provides an anti-reflection film (hereinafter referred to as A) having unevenness as described above.
In order to form an anti-reflection film containing a metal oxide, a film for an anti-reflection film containing a metal oxide is printed using a screen printing method, preferably using a plate having a mesh of 50 to 8 oo mesh, and smooth irregularities corresponding to the mesh are formed. ARP having a thickness of %K of 600 to 100OA (D) is to be formed.

Conventionally known methods for forming an antireflection film include a coating method using a spinner, a vacuum deposition method using vacuum evaporation such as 810, and a spray method in which a film is formed by spraying.

However, 90% of the materials used in all of these materials were wasted without being effectively utilized, which became a very serious factor in increasing costs when trying to make low-cost solar cells.

Furthermore, in the coating method, when the peripheral part does not have a circular or similar shape, for example, in the case of a rectangular semiconductor with the highest area efficiency, the thickness at the peripheral part is locally thick.
The reflectance as an anti-reflection film was also high, and the color tone changed in appearance, lowering the product value.

When I tried to create a flexible window, it was completely impossible, and I had no choice but to selectively etch it using a photo-etching method after it was formed.

However, the present invention not only overcomes all of these drawbacks, but also eliminates the problem of providing unevenness on the surface of the ARP.
,>ARP has the characteristic of reducing the reflectance of the semiconductor surface in a wide wavelength range by causing light to be reflected one or more times, that is, diffusely reflected.

In other words, on a flat surface, the wavelength range for a reflectance of 10 cm or less was 450-600 nm, but now it is 400-750 nm.
When extended to K, a peak is formed, which has a synergistic effect in that the reflectance of the apparent dust wavelength light is lowered in the concave portions, and the reflectance of long wavelength light is lowered in the convex portions.

In the present invention, silicon oxide may be further added to the screen printing ink and titanium oxide for adjusting the refractive index, and tantalum oxide may be used instead of butane oxide to prevent light absorption in the short wavelength region.

Furthermore, ARII' may be used in combination with a dopant as a diffusion source of impurities in the semiconductor immediately below it.
In that case, for example, phosphorus glass or boron glass may be added at the same time to diffuse impurities together with sintering after screen printing.

The present invention will be explained in detail below.

FIG. 1 is a vertical sectional view showing the method for manufacturing a photoelectric conversion device of the present invention.
cm semiconductor (1) (single crystal or polycrystalline semiconductor) 1
A semiconductor layer (2) having a conductivity type of 7 was provided on the substrate with a thickness of 1□ to 40011 mm or 100 mm.

This semiconductor layer was formed by coating high-concentration phosphorus glass with a spinner and heating and diffusing it at a temperature of 850 to 950°C. Sheet resistance 10-100 Yuno; X≦
0.5μ typically 0.2μ.

Furthermore, a square-shaped electrode was formed on this upper surface by screen printing using silver paste, aluminum paste, or nickel paste.

One electrode was 0.2 to 0*3trx m with an electrode spacing of 3 to 5 mm. After printing the electrode (7) and the external lead electrode (6) in this way, 150 to 30
Prebaking was carried out at 0@C, and an antireflection film (3) was printed on the upper surface by screen printing to a thickness of 600 to 1000A (for example, 800±5OA (thickness after baking)). Furthermore, pre-bake this ARP (150 ~
300°030 minutes) and then repeat these steps at 400° to 950°.
Temperature in °C typically 10-3 at 500-75060
It was sintered for 0 minutes and fired.

When performing this screen printing, the external extraction electrode (6)
A plate was used in which a mask was formed to prevent ARP from being printed in the area.

In this way, conventional ARII' could be coated on the entire surface, which greatly contributed to lower prices.

FIG. 2 is an enlarged view of a part of the photoelectric conversion device shown in FIG.

That is, a transparent dielectric type semiconductor layer (
2), electrode (7), external extraction electrode (6), back electrode (
4) shows an anti-reflection film (3) with concave and convex portions. , vertical pitch.Furthermore, the electrode of the ARP of the present invention is covered with an oxide metal to improve water resistance and durability, and the external lead electrode (6) can be used with other photoelectric conversion devices. In order to modularize and connect in series or parallel, the electrodes are exposed and soldered using lead wires.

The photoelectric conversion device thus obtained was AMI (100 m W
/c mt), open voltage 0.55~0.60V short circuit current' 35~40rn A/cm m', conversion efficiency 14
~16% can be obtained, compared to conventional coating methods, etc.
It was possible to improve P by 910-15% from 13-14.5%. Furthermore, the manufacturing cost is 220m per 100m' using a conventional 100mD substrate (unit price 1000 yen).
0 yen (1) OOFl/W) becomes 1800 yen (1300F1/'W) and the unit IW at 2 price is 40
A major feature is that we were able to lower the price by as much as 0 yen.

The embodiment of the present invention is a P
An N'' junction type solar cell has been shown. However, even if this is in the lateral direction, the present invention can also be applied to other structures such as P-N junction, M-S structure, etc. It goes without saying that the invention should be applied to all photoelectric conversion devices, such as photo sensors, arrays, and image sensors.

[Brief explanation of the drawing]

FIGS. 1(4) and 1(B) are vertical sectional views of a photoelectric conversion device showing the present invention. FIG. 2 is a vertical sectional view of the photoelectric conversion device, partially enlarged from FIG. 1(B). kjjoi regret 2

Claims (1)

[Scope of Claims] 1. A photoelectric conversion device characterized in that an antireflection film of a metal oxide having smooth irregularities is provided on the light irradiation surface of a semiconductor that generates photovoltaic force. 2. In claim 1, the metal oxide is provided so as to cover the upper surface of the electrode selectively provided in contact with the upper surface of the semiconductor, and to expose the external lead electrode portion of the electrode. Photoelectric conversion device. 3. A photoelectric conversion device according to claim 1, wherein the semiconductor has a rectangular shape. 4. In claim 1, the anti-reflection film contains 60%
A photoelectric conversion device characterized in that it is made of a metal oxide whose main component is titanium oxide and has a thickness of 0 to 100 OA.