JPH04111474A - Optical converter - Google Patents

Abstract

PURPOSE:To arrange static electricity to bypass a grounding electrode and hence protect a semiconductor film even when high voltage is applied between electrodes by installing a grounding electrode to at least one party of electrodes out of two electrodes in parallel in a photoelectric conversion device which is provided with a light received plane electrode on a transparent insulation board, and a semiconductor film thereon and a rear side electrode on the semiconductor film. CONSTITUTION:A light received plane electrode 2 which forms two light received regions 2a and 2b on a transparent insulation board 1 which receives light L, is installed where the light received plane electrode 2 and a grounding electrode 3 are patterned and installed. A semiconductor film 4 with an opening respectively is installed o these electrodes 2 and 3. Furthermore, patterned rear sided electrodes (5a, 5b, and 5c) on the semiconductor film 4 are installed. The rear sided electrode 5c is covered so that the grounding electrode 3 may be common with the negative electrode of the semiconductor.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to photoelectric conversion devices such as light receiving elements and solar cells;
More specifically, the present invention relates to a photoelectric conversion device in which damage to a semiconductor film due to static electricity is prevented by providing a ground electrode.

[Conventional technology]

A conventional amorphous silicon (A-3i) solar cell has indium tin oxide (Int.

= ・S n Ot ; I To) light-receiving surface electrode 11
, a-3T film 12 with pin type structure, metal back electrode 13
and a resin protective film 14 are sequentially laminated.

However, when a statically charged human body or the like touches the protective film 14 or the glass substrate 10, which is an insulator, that area becomes locally charged. Therefore, the light-receiving surface electrode 11 and the back surface electrode 1
A high voltage is applied between a-3ig! When a current flows through the structural defects (such as cracks and minute pinholes) in the a-3i film 12, the a-3i film 12 is destroyed and its characteristics are significantly degraded.

Therefore, in order to avoid the above problem, conventionally, the glass substrate 1
0 and the light-receiving surface electrode 11 with an insulating film interposed therebetween (see Japanese Patent Laid-Open No. 59-54269, etc.), or a protective film 14 with an insulating adhesive interposed between the ground electrode and the ground electrode. Structure in which conductive foil is applied (Utility Model Application No. 61-1)
34058, etc.), even if static electricity is applied between the light-receiving surface electrode 11 and the back surface electrode 13, current is caused to flow through the ground electrode.

[Problem to be solved by the invention]

However, the above technology requires a special manufacturing process to provide the ground electrode, which has previously caused problems (such as having adverse thermal and mechanical effects on the formed light-receiving surface electrode and semiconductor film, and even causing the ground electrode to By providing this, new problems have arisen, such as an increase in the size of the entire device.

Therefore, the present invention was devised in view of the above problems, and it is possible to easily form a ground electrode by using conventional manufacturing processes, and also to prevent the device from becoming larger even if a new ground electrode is provided. The purpose of this invention is to provide a photoelectric conversion device.

[Means to solve the problem]

The above problem is solved by the means described below.

That is, a photovoltaic device in which a light-receiving surface electrode is provided on a light-transmitting insulating substrate, a semiconductor film that receives transmitted light from the insulating substrate side is provided on the light-receiving surface electrode, and a back surface electrode is provided on the semiconductor film. The above problem is solved by a photoelectric conversion device characterized in that a ground electrode connected to the semiconductor film is arranged in parallel with at least one of the two electrodes.

[Effect]

In the photoelectric conversion device of the present invention, since the ground electrode is provided within the electrodes at both ends of the semiconductor film, and is arranged in parallel with at least one electrode and in contact with the semiconductor film, even if a high voltage is applied between the light-receiving surface electrode and the back surface electrode Even if static electricity is applied, it bypasses the ground electrode, and the semiconductor film is not destroyed by static electricity that has no place to escape, unlike in the conventional case.

In addition, no special manufacturing process is required to form the ground electrode, and the ground electrode can be formed at the same time as the electrode of the semiconductor film, allowing photoelectric conversion without increasing the number of conventional manufacturing steps. The device can be manufactured easily.

〔Example〕

An embodiment according to the present invention will be described in detail based on the drawings.

The photoelectric conversion device Sl of this embodiment is an a-3i photodiode for cameras that can sense the amount of received light with two light receiving sections, and an exploded perspective view thereof is shown in FIG. Reference numeral 1 denotes a light-transmitting insulating substrate that receives light, on which a light-receiving surface electrode 2 with two light-receiving regions 2a and 2b formed is provided, and the light-receiving surface electrode 2 and a ground electrode 3 arranged in parallel thereto are patterned. A semiconductor film 4 having an opening is provided on each of the electrodes 2 and 3, and a back electrode 5 (5a, 5b, 5c) patterned on the semiconductor film 4 is provided. In addition,
The back electrode 5C is coated so that the ground electrode 3 and the cathode side of the semiconductor are common.

A second plan view of the photoelectric conversion device S1 seen from the back electrode 5 side.
As shown in the figure. However, for simplicity, illustration of the semiconductor film 4 and back electrode 5 is omitted, and only the insulating substrate 1, the light-receiving surface electrode 2, and the grounding electrode 3 are shown.

Here, the light-receiving surface electrode 2 has a center diameter of about 0.3 to 0.6 mm.
A central light receiving part 2a formed in a circular shape, a peripheral light receiving part 2b having a circular shape at the center and a rectangular shape with a length of about 1.5 mm and a width of about 2.5 mm, and a central light receiving part 2a and a peripheral light receiving part 2b. and a ground electrode 3 arranged in parallel between the two and connected to a ground (not shown). Here, the central light receiving section 2a and the peripheral light receiving section 2
The distance from b is about 200 μm or less, preferably about 50 μm
The following shall apply.

Next, a method for manufacturing the photoelectric conversion device Sl will be explained for each layer.

Insulating Substrate 1> As the insulating substrate 1, a well-cleaned glass substrate with a thickness of about 0.2 to 5 mm is used. If the glass substrate contains a large amount of impurity elements such as alkali metals, first coat the surface with an insulating film such as silicon oxide (SiO□) to prevent the impurities from diffusing into the light-receiving surface electrode 2. good.

Light-receiving surface electrode 2 and ground electrode> To form the light-receiving surface electrode 2 and ground electrode 3 on the insulating substrate 1, the temperature of the insulating substrate 1 is heated to approximately 50 to 600°C, and tin oxide (SnO2 ) or the light-receiving surface electrode 2 and the ground electrode 3 are coated with a transparent conductive film mainly made of ITO. These electrodes 2 and 3 are formed to a thickness of approximately 0.03 to 0.5 μm by various chemical manufacturing methods (spray method, CVD method, etc.) or physical manufacturing methods (electron beam evaporation method, sputtering method, etc.).

In this example, first, the electrode 2 is
, 3 such that the fluorine (F) concentration is approximately 0.05 to 30 wt%.

Mixed gas such as hydrogen fluoride (HF), oxygen (02), or S n C141 water vapor (H20), oxygen (02),
1.l-difluoroethane (CH3CHF2), nitrogen (
The film thickness is approximately 0.06μm by using a mixed gas consisting of N2) etc.
A doped layer of F is formed.

Furthermore, an undoped layer of about 0.05 .mu.m or less, more preferably about 0.02 .mu.m or less, containing no F is formed using only a mixed gas such as 5nCI4.02, for example, on this layer. Here, the F doped layer is an impurity mainly for improving the film quality of the light-receiving surface electrode 2, and this impurity may be antimony (Sb) or the like in addition to F. However, if a substance such as sb is mixed into the semiconductor film instead of F but does not impair the characteristics of the semiconductor film, the undoped layer is approximately 0.01
It may be an extremely thin layer of μm or less. By providing a non-doped layer of F in this manner, the incorporation of F into the semiconductor film 3 is prevented as much as possible, thereby avoiding deterioration of the characteristics of the semiconductor film 4. Here, the patterning of the electrode 2.3 is performed by photo-etching or the like to form two light-receiving parts 2a and 2b, but the light-receiving surface electrode 2 can be further divided to form more light-receiving parts. I don't mind if you do. In addition, the electrode 2
, 3 can be modified and implemented as appropriate if both are arranged side by side.

In this embodiment, since the material and thickness of the ground electrode 3 are the same as those of the light-receiving surface electrode 2, the ground electrode 3 can be formed at the same time as the conventional light-receiving surface electrode 2. Furthermore,
The ground electrode 3 does not necessarily have to be present on the same substrate surface as the light-receiving surface electrode 2.

Further, its material and thickness do not necessarily have to be the same as those of the light-receiving surface electrode 2, and it does not have to be translucent as long as it has conductivity, so it may be made of, for example, a metal film or a conductive paste.

Semiconductor film 4> On the insulating substrate l, the light-receiving surface electrode 2, and the ground electrode 3,
Hydrogenated amorphous silicon (a-3i) with a thickness of about 1 μm
:H) A semiconductor film 4 is formed. This semiconductor film 4 has three layers of p-1-n structure, and each layer is made of plasma carbon.
Formed by VD method.

First, a p layer is formed. For example, a-3i:H film forming gas such as silane (SH4, etc.) and impurity doping gas such as borane (B286 etc.) are mixed so that, for example, B zHs/S i H4 is 0.1 or less. The amount of impurity doped is controlled by setting the flow rate ratio of the impurity doping gas to the a-3i:H film forming gas.

In this state, due to glow discharge, the thickness is about 0.005~0.
A p-layer with a thickness of about 0.03 μm is formed. Note that the impurity doping gas in this case may be one containing, for example, a group Ⅰ element that acts as a p-type dopant for silicon.

Next, an i-layer is formed on the p-layer. That is, the a-3i:H film is formed without using the impurity doping gas as described above. Here, the thickness of the i layer is approximately 0.3 to 1 μm.
That's about it.

Next, an n layer is formed on the i layer. That is, a-3i
:H For example, silane (SiH4, etc.) is used as a gas for forming the film, and phosphine (PH, etc.) is used as an impurity doping gas.
etc.), and the amount of impurity doped is controlled by setting the flow rate ratio of the impurity doping gas to the a-3i:H film forming gas so that, for example, PHI/SiH4 is less than o, i.

In this state, due to glow discharge, the thickness of about 0.02 to 0.1
An n-layer with a thickness of approximately μm is formed. Note that the doping gas may be one containing, for example, a group Ⅰ element that acts as an n-type dopant for silicon. Further, the method for forming each layer of the semiconductor film is not limited to the above method, but may be a sputtering method or the like.

Back Electrode 5> Next, the back electrode 5, which is a metal film, is formed on the semiconductor film 4 by patterning. That is, aluminum (AI
), nickel (Ni), chromium (Cr), titanium (Ti
), a single metal such as silver (Ag), or an alloy made of a combination thereof is formed by a vacuum evaporation method or the like.

Next, a description will be given of the result when static electricity is applied to the photoelectric conversion device S1 having the above configuration.

If no ground electrode 3 is provided, the maximum electrostatic withstand voltage is about ±50V at most, but for a photoelectric conversion device with the above configuration, for example, if static electricity of ±200V and 200pF is applied between the light-receiving surface electrode and the back surface electrode. Even after three times of application, the semiconductor film 4 was not destroyed and its characteristics did not deteriorate. this is,
This is because static electricity flows to the ground through the ground electrode 3.

FIG. 3 shows a schematic sectional view of the central part of a photoelectric conversion device S2 of another embodiment, and FIG. 4 shows a back electrode 5 of the photoelectric conversion device S2.
A plan view seen from the side is shown.

In this embodiment, instead of arranging the ground electrode 3 in parallel with the light-receiving surface electrode 2 as in the photoelectric conversion device S1, a ground electrode 6 is provided in parallel with the back electrode 5 to achieve the same function as the photoelectric conversion device S1. The photoelectric conversion device S2 shown in FIG.

Therefore, the manufacturing process of the photoelectric conversion device S2 is almost the same as the manufacturing process of the photoelectric conversion device S1 described above, and the main difference is that the light-receiving surface electrode 2 is formed without photo-etching, The electrode 5 and the ground electrode 6 are photo-etched to create desired separation areas (5a, 5b).
, 6). In addition, photoelectric conversion device S1
In this embodiment, the back surface electrode 5 serving as a cathode was a common electrode with the ground electrode 3, but in this embodiment, the light receiving surface electrode 2 serving as an anode is a common electrode with the ground electrode 6. A ground electrode 6 arranged in parallel with the back electrode 5 and in contact with the semiconductor film 4 is connected to the ground E.

In this example as well, the semiconductor film 4 was not destroyed even when static electricity was applied under the same conditions as in the photoelectric conversion device Sl. This is also because static electricity flows to the earth E through the earth electrode 6.

In this embodiment, a ground electrode is provided in parallel with either the light-receiving surface electrode 2 or the back surface electrode 5, but a ground electrode may be provided in parallel with both the electrodes 2 and 5. Further, in this embodiment, an example of an a-3i photodiode for a camera is shown as an optical semiconductor device, but it goes without saying that the present invention can also be applied to photoelectric conversion devices such as color sensors and solar cells.

〔Effect of the invention〕

As explained above, the photoelectric conversion device of the present invention can be realized by providing a ground electrode in parallel with at least one of the light-receiving surface electrode and the back surface electrode, and in contact with the semiconductor film, even if the light-receiving surface electrode Even if high-voltage static electricity is applied between the back electrodes, the static electricity is smoothly discharged through the ground electrode, making it possible to prevent electrostatic damage and property deterioration of the semiconductor film as much as possible.

In addition, the formation of the ground electrode can be performed at the same time as the conventional electrode manufacturing process, so there is no need for special processes unlike in the past, and there is no need to prepare a special substrate or material for electrostatic withstand voltage. An inexpensive and compact photoelectric conversion device can be provided.

Furthermore, the provision of the ground electrode does not increase the size of the entire device, and is particularly suitable for photodiodes for cameras, which require extremely small light-receiving areas and high reliability.

[Brief explanation of the drawing]

FIGS. 1 to 4 are diagrams showing embodiments according to the present invention,
Fig. 1 is an exploded perspective view showing one embodiment of the photoelectric conversion device, Fig. 2 is a plan view showing the positional relationship between the light-receiving surface electrode and the ground electrode, and Fig. 3 shows another embodiment of the photoelectric conversion device. The longitudinal sectional view and FIG. 4 are plan views seen from the back electrode side of FIG. 3. FIG. 5 is a longitudinal sectional view of a conventional photoelectric conversion device. Transparent insulating substrate, light-receiving surface electrode, ground electrode, semiconductor film, back electrode.

Claims (1)

[Claims] A photoelectric conversion device comprising a light-receiving surface electrode provided on a light-transmitting insulating substrate, a semiconductor film for receiving transmitted light from the insulating substrate side provided on the light-receiving surface electrode, and a back electrode provided on the semiconductor film. A photoelectric conversion device characterized in that a ground electrode connected to the semiconductor film is arranged in parallel with at least one of the two electrodes.