JPS5835989A - Amorphous photo-semiconductor device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to an amorphous optical semiconductor device.

Optical semiconductor devices such as solar cells that convert sunlight into electrical energy and optical sensors that detect optical signals as electrical signals are now equipped with amorphous semiconductors instead of conventional single crystal semiconductors. It's here.

Such amorphous semiconductors are formed using a manufacturing method such as a plasma discharge method that is completely different from single crystal semiconductors, and their manufacturing energy and processes are simple, allowing for continuous mass production, and they use fewer materials. It has many excellent features such as ease of use.

The first @ shows a conventional optical semiconductor device comprising an amorphous semiconductor, (1) is a transparent substrate made of an insulator such as a heat-resistant resin, and (2) is the substrate (1). - A transparent electrode film of tin friend oxide 5nOv, indium oxide InzO5, indium tin oxide n20s-8nO2, etc. deposited on the main surface, (
31ut! IN Ming N * Ml (21 upper Vc Shihun E3
The semiconductor film (3) is an amorphous semiconductor film such as amorphous yycon (a-8i) formed by defsumer discharge in a 1Hs atmosphere, and the semiconductor film (3) is impurities such as VpofunB2H6@7rnufuinPH1 and the like for 5IHs. By adding it to the atmosphere, it is possible to control P-type and N-type, and this conventional example has a five-layer structure in which P-type, T-type, and Nfil layers are laminated. (4) is above the amorphous semiconductor @ (3)! ! Applied 7/Mfi: 17AAl, back metal film such as gold Au, (
5) a first lead wire fixed to the back metal film (4) by ultrasonic bonding and silver paste with a conductive adhesive; (6) dlllll first lead 11 (5);
A by ultrasonic bonding, conductive adhesive as well as
1. Transparent electrode film (2) via electrode pad (7) made of Au etc.
), (8) is connected to the back metal '! II (41 etc.) is an epoxy-based mode μ mode body.

In the amorphous optical semiconductor device having such a structure, a transparent substrate (1) and a transparent electrode [! II(z) is transmitted through the amorphous semiconductor layer (
When 3) is irradiated with light, holes and/or electrons are generated in the semiconductor layer (3), and a photovoltaic force is generated between the transparent electrode film (2) and the back metal film (4). Ru. and.

The above photovoltaic force is the first and second glued @ (51(6)
It is taken out to the outside via.

However, according to such a structure, -rIlj of the back surface gold IEII (4) present on the back surface of the amorphous semiconductor layer (3) when viewed from the light irradiation surface of the transparent substrate (1) is covered by the mold body). Although it is difficult to understand! 1! When viewed on a long-term scale, the mode body (8) allows moisture to pass therethrough, albeit to a small extent, so there is a risk that the metal film on the rear surface (4) may be corroded. In particular, the amorphous semiconductor film (31) to which the other side of the back metal film (4) is adhered has more lattice defects than a single crystal semiconductor, generally lacks crystallinity, and is porous! IC,
@The thickness is usually on the order of microns or less, forming a thin film. Therefore, as schematically shown in FIG. 2, if a part of the back pot 11 (4) is corroded by moisture, the moisture permeates through the corroded part (9) and the buyer conductor layer (3
) due to its porous and thin film shape, it diffuses over the entire area of 8rNJ between the semiconductor layer (1) and the back metal film (4), and begins to erode the back metal film (4) from the interface direction as well. In other words, the back metal 11(4) is corroded by moisture from both the exposed surface and the interface, and has a disadvantage in terms of reliability compared to conventional single crystal semiconductors.

The present invention has been made in consideration of these points, and is as follows:
An embodiment of the present invention will be described in detail with reference to 1lI311 and tv#.

The third factor is a sectional view showing an embodiment of the present invention, which corresponds to the conventional example shown in FIG.
A number is attached. That is, (1) is a transparent substrate.

(2) is a transparent film [11, (3) is an amorphous semiconductor film, (4
) is the back metal film, (5) is the first lead wire, (6) is the second lead wire, (7) is the electrode pad, and is different from the above back metal! (4) is coated with a protective metal film αG'''C which is more moisture resistant than the back metal film (4) in order to prevent corrosion due to moisture.

In this way, the present invention is based on the back metal I! (4) and insulation metal film (
The moisture resistance of the metal composition that forms the

Therefore, the present inventor has developed metal aluminum Al, gold Au, silver Ag, copper Ou, which can form both metal films (4) and (2).
yke IvNi, tin Sn, lead p'b, yke IvNi, tin Sb,
FiiZn, Indium En, Titanium T1, Molybdenum MO% Tungsten W% are empirically classified into Groups 1 (hereinafter abbreviated as G1) to Group 4 (hereinafter abbreviated as G4) based on those with good moisture resistance as shown in the table below. did.

The material of the protective metal film ao may be appropriately selected from G5, and if used as the Out-back metal film (4) of G2, it may be selected from G1. As another example of a combination, the back metal film (4) is made of t-Al-, and the protective metal is an alloy of A1 and the metals in 01 to G3, for example, Al-T
It may be formed of Ti, Al-Au, etc., and may also be formed of other alloys such as Ti.
-Ag, Mo-Ag, etc. may be used.

In this way, the back metal film (4) and the protective metal film αO can be made of a single substance or an alloy of the metal if the protective metal film αO is a metal with higher moisture resistance than the metal forming the back metal all (4). I don't mind. Furthermore, the protective metal film α0rs is not limited to one layer, but may be multilayered. In this case, if the ohmic properties are good, the order of lamination is, for example, backside metal film (4) force; A1, protective metal at (2) MO, Sn multilayer. Structure (MO and Sn
The moisture resistance may be reversed.

Incidentally, the E#13G1 to G40 metals are appropriately selected and formed by a method such as vacuum evaporation, electron beam evaporation, or spar/9 ring.

Next, a specific embodiment of the present invention is shown in FIG. The amorphous optical semiconductor device of the present invention shown in FIG. 4 has a PINIP composite a-
It includes an amorphous semiconductor film (3) of Sl, a back metal film (4) made of Al, an MO layer (10a), and a Sn layer (1).
It has a protective metal film (to) with a multilayer structure in which 0b) is laminated in sequence. The above amorphous semiconductor film (3) t! - Machining on main surface
TOS-8nOz 03m Bright Electrode A transparent substrate (1) made of glass covered with an electrode (2) is placed between the electrodes of the plasma reactor, and by adding B2H6 to SiH4 gas, a thickness of 50~ 2 layers (5p) of about 100A, 1 layer (31) of about 5000 to 7000A using only Sir4 gas, and N layer (3n) of 500A or less by adding Sj and Ha gas KPH5 after m. It can be deposited on the light-transmitting substrate (1).

Then, the back metal film (4) of A1 is formed with a thickness of 1μJllK by vacuum evaporation method, and the MO layer (10aJm and KS
n-layer (I Qb) O 1 [i Gold JII film ω was deposited with a thickness of 2000 mm by electron beam evaporation method and d vacuum evaporation method, respectively.
~3000A, 3000~5000A stacked.

This issue 1' [ffl such MOMl (IQa) and 5nl
Protective metal WIIa consisting of a multilayer structure of II (101))
In order to compare the device of the present invention equipped with an IJ and the conventional device without the above-mentioned protective metal film ω, a gi degree of 60°C and a humidity of 9
A reliability experiment was conducted in which the device was left in a constant temperature and humidity atmosphere of 0% for a long period of time, and the following results were obtained.

As described above, in the present invention, no defects occur even after 1000 hours of standing time, and even after 2000 hours and 4000 hours, the defective rate can be suppressed to 1/3 or less of that of the conventional device.

By the way, in the conventional device, the first and second glue dots j1 (S
) (@) fllE1m III (4) and the electrode pad (7) are fixed by ultrasonic bonding or a conductive adhesive. When performing ultra-f wave bonding to the back metal film (4) on the amorphous semiconductor@r3), there was a risk that the amorphous semiconductor layer (3) below the amorphous semiconductor layer (3) would be destroyed due to the ultra-f vibration. This is due to the fact that the amorphous semiconductor #(1) is a thin film of micron ohm or less.
It has been confirmed that the time-varying efficiency of an ultra-thin film of d microns or less is the highest when used as a solar cell as shown in the *m example above. It is relatively high.

On the other hand, those using conductive adhesive have very poor workability.

However, according to the present invention, the uppermost layer KS of the protective metal film αG
By disposing a solderable metal such as n, Ag, Ni, etc., the first lead wire (5) can be fixed by soldering, and a thin film-like amorphous semiconductor @ (3
), it is possible to firmly connect the two mechanically without damaging the joints or impairing workability. In this case, if a metal film α1) made of the same material as the protective metal film αG is formed on the electrode pad (7) as shown in FIGS. 3 and 4, the second lead wire (6) and the electrode pad (7) ) can be soldered in the same way as the first y-domain wire (6).

As is clear from the above description of the amorphous optical semiconductor device of the present invention, the back Iff metal film laminated on the amorphous semiconductor film is a protective metal film that is more moisture resistant than the back metal film! lI
Since the metal film on the back surface is covered with water, corrosion due to moisture can be prevented and a highly reliable device can be obtained.

[Brief explanation of drawings]

1(2) is a sectional view of the conventional device, FIG. 2 is a schematic diagram for explaining the drawbacks of the conventional device, FIG. 6d is a sectional view of an embodiment of the device of the present invention, and FIG. Example cross-sectional views are shown, respectively. (1)...---Transparent substrate, (3)...Thin film-like amorphous semiconductor film, (41----back metal film, α
υ・・・Protective metal film.

Claims (1)

[Claims] (1) ii. At least a thin amorphous semiconductor film and a back metal film are sequentially laminated on one main surface of the photosensitive substrate, and the back metal film is covered with a protective metal film having higher moisture resistance than the back metal film. Nine amorphous optical semiconductor devices characterized by: