JPH031577A - Photoelectric converter - Google Patents

Abstract

PURPOSE:To facilitate manufacture and to enhance its efficiency by composing transparent electrodes in part or all of first and second electrodes on the face of a semiconductor layer of the side to be irradiated with a light, and providing the layer and the first or second electrode with an end of schematically the same shape on a substrate. CONSTITUTION:A conductive electrode 2 is selectively formed on an insulating board 1, and its upper face is coated with a semiconductor layer 3 and a second electrode material 4 made of a transparent conductive electrode. The semiconduc tor layer is so manufactured as to generate photovoltaic power by irradiating a PN junction, a PIN junction, etc., with a light. Thereafter, a semiconductor layer 12 and a transparent conductive electrode 11 of unnecessary parts are removed with the same mask by etching. Thus, the layers 12, 12' are etched schematically in the same shape as those of the patterns 11, 11' of the transpar ent electrodes. That is, with the transparent electrode as a mask the semiconduc tor layer is etched, and a trapezoidal shape and its side periphery are taper etched. As a result, the shape of a lead to a bus line of a substrate does not allow possible disconnection along the side periphery of the semiconductor layer by the first electrode, thereby enhancing its reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a first electrode on a soft or hard insulating substrate, a non-single crystal semiconductor doped with hydrogen or a halogen element that generates photovoltaic force, and a first electrode on the first electrode. The present invention relates to a photoelectric conversion device in which a transparent electrode constituting part or all of one electrode and a semiconductor in close contact with the electrode have approximately the same shape in a semiconductor device having two electrodes.

The present invention provides a semiconductor device that generates a plurality of photovoltaic forces on an insulating substrate, and uses one of the transparent electrodes as a mask to selectively remove the semiconductor below it, or uses the semiconductor as a mask to selectively remove the transparent electrode. The present invention relates to a method for manufacturing a photoelectric conversion device in which a transparent electrode and a semiconductor are formed into substantially the same shape at some end portions by removing the transparent electrode and the semiconductor.

In order to reduce reverse leakage around the side of the semiconductor constituting the backflow prevention diode and the semiconductor that generates photovoltaic force, the present invention has a trapezoidal tapered or beveled shape around the side, and such a structure. During the plasma etching process of the semiconductor layer, one electrode is placed vertically, horizontally,
It is characterized by etching while vibrating back and forth.

That is, in order to configure a photoelectric conversion device as a system that is less expensive and has high reliability, it is necessary to provide (1) first and second electrodes, (2) a semiconductor layer that generates photovoltaic force, and (3) the device. (4) Terminals for electrical connection with the outside, (5) Various mechanical adhesion properties of the terminals to the substrate, (6) (7) The first and second electrodes and the semiconductor layer are guaranteed against mechanical strain; (8) The semiconductor layer has high photoelectric conversion efficiency. , is necessary.

In addition, as a photoelectric conversion device, (9) the manufacturing cost of the semiconductor layer is low; (10)
A conversion device using a semiconductor layer is easy to manufacture and has a simple structure; (11) this accessory equipment is not expensive compared to a semiconductor layer; (12) the conversion device is easy to handle; (13) ) High long-term reliability is important.

However, in the case of conventional photoelectric conversion devices, the semiconductors that generate photovoltaic power themselves are expensive, and therefore no consideration has been given to the device as a system that includes its auxiliary equipment.

In order to meet these various requirements, the present invention aims to make a transparent electrode and a thin film of a non-single crystal semiconductor doped with hydrogen or halogen elements have approximately the same shape, and to pursue ease of manufacturing and high efficiency. This is what I did.

Conventionally, for example, if you try to make a solar cell using the current CZ (Czochralski) slice, it costs 10KW/year, and assuming that the silicon raw material is 8000 tons/year, it costs 1KW/year.
It costs 4,160 yen per person. Moreover, the cost increases by 74%, or 3,070 yen, in the cell section that generates photovoltaic force. Furthermore, other modular equipment costs 1,090 yen (26%).

However, this price is 4160 yen/1/100
There are many difficulties in reducing the price to 40 yen/-. For example, the wafer used for the cell part has the precision of a substrate having mechanical strength. Therefore, when the cell part is made of a semiconductor, if the thickness of the semiconductor such as silicon used for the cell part is 1 to 2 .mu.m, a substrate is always required. In addition, terminals for connecting external leads from the substrate cannot be directly bonded to the semiconductor layer.

For this reason, the semiconductor layer is simply sold at 1/10 from 3070 yen/W.
Even if it were possible to reduce the cost to 0.30 yen/-, it would end up costing more than ever to make it modular.

In order to eliminate such drawbacks, the present invention looked at conventional solar cells in a larger system and considered the necessary requirements there. As a result, in the past, there was no need to assemble multiple silicon slices, and even if some solar cells were damaged, backflow prevention diodes were required to prevent the solar cells from shorting out and causing loss of power. However, in the present invention, the loss of such a system is used as a substrate, and a semiconductor layer on the upper side of which is the same as the semiconductor layer that generates photovoltaic force is used as a backflow prevention diode, and in addition, this substrate is used as a substrate that ensures mechanical distortion of the semiconductor layer. In addition, an external lead-out end is also attached, and at least two pass lines, one positive and one edible, are provided on this substrate, and a plurality of semiconductor layers arranged in a matrix are formed into a matrix by using these pass lines. The feature is that the entire system is integrated into one.

Another major feature of the present invention is that it uses etching, photoetching, or selective printing for such low-cost manufacturing, and can be completed in three to four mask steps. In particular, the manufacturing process is simplified by making the semiconductor layer and the transparent electrode of one of the first or second electrodes approximately the same shape, and the electrode is provided apart above the substrate surface along the side surface of the semiconductor layer. It has features such as the provision of leads that reach the substrate.

The present invention will be explained below with reference to the drawings.

FIG. 1 shows the manufacturing process of the conversion device of the present invention using a longitudinal sectional view.

In the drawing, (A) shows a conductive electrode (
2) is selectively formed. If a photo-etching process is used, use the ■th photomask. However, selective plasma etching or printing may be used to simplify and reduce costs.

As the substrate material, methacrylic resin, epoxy resin, especially glass-epoxy composite material (commonly known as GALA-EPO), fluororesin, polycarbonate, glass, alumina and other ceramics, and hard substrates were used. Polyimide, polyester, silicone resin, etc. were used as the flexible and soft substrate.

For the first conductive electrode, a material with excellent adhesion to the substrate was used. For example, it may be a two-layer film in which chromium is formed on a glass substrate and aluminum is further formed on the top surface.

In FIG. 1(B), this upper surface is coated with a second electrode material (4) consisting of a semiconductor N (3) and a transparent conductive electrode.

The semiconductor layer is a PN junction, a PIN junction, a PINPIN junction,
PNPN...A PN junction, a PI IN junction, etc. were prepared in such a way that a photovoltaic force could be generated by light irradiation.

The semiconductor layer used in this example is a non-single crystal semiconductor such as polycrystalline or amorphous, and its energy gap (Eg) is continuous light such as sunlight or fluorescent light, and this continuous light can be efficiently used. A W-N structure was used to ensure good photo-electrical conversion. In other words, increase the Eg on the light irradiation side, that is, 2 to 3 of W-Eg (WIDE Eg).
ev, and reduce Eg on the opposite side, that is, N-Eg (
NALLOW Eg ) was set at 0.7 to 1.5 eV.

As a semiconductor material, silicon is the main component, and C+
N, 0. Ge+ Sn, pb, In+ Sb
+Te was added as needed. In addition, the semiconductor layer was mainly formed using a low pressure CVD method or a glow discharge method. For these, patent applications for inventions by the present inventor, Japanese Patent Application No. 53-0868671086868, Japanese Patent Application No. 54-03
No. 20701032071 and is described in Japanese Patent Application No. 49-071738.

Thereafter, as shown in FIG. 1(C), unnecessary portions of the semiconductor layer (12) and the transparent conductive electrode (11) were removed using the same mask in a second etching step (2). This etching creates transparent electrode patterns (11) (1
Semiconductor layer (12) (12') in approximately the same shape as 1')
was etched. That is, the semiconductor layer was etched using the transparent electrode as a mask. Further, this semiconductor layer has a trapezoidal shape, and the periphery of the trapezoid is tapered etched. Actually, a fluorine-based plasma elastomer was used. That is, in a plasma etching apparatus having parallel plate type electrodes,
The part where the metal mask is used as a transparent electrode and the semiconductor layer is left (11) (
11') (12) (12'), and plasma discharge was selectively applied only to the part to be removed. At that time, plasma discharge was caused between one common electrode under the substrate and ten opposing electrodes on the substrate slightly spaced apart from the substrate transparent electrode. In this way, there is no need to use a photoresist or the like, and the transparent electrode and semiconductor layer are not mechanically damaged in any way. During this selective plasma etching, if the ten opposing electrodes are periodically vibrated and moved up and down or left and right and back and forth at a speed of 1 to 10 c/s with a width of 1ffllll to 1 cm, the edge of the discharge becomes blurred, and as a result, the semiconductor The periphery of the side of the layer can be tapered into a trapezoidal shape, and in addition, the angle of this taper can be approximately 45° relative to the substrate when the etch rate is the same, and when doubled, it can beveled to approximately 30°. did it.

As a result, the lead formation from the first electrode to the pass line of the substrate along the side periphery of this semiconductor layer can be made extremely reliable without the possibility of disconnection. Furthermore, in the case of the reverse current prevention diode, it was possible to increase its reverse breakdown voltage and substantially expand the depletion layer at the PIN junction interface.

In FIG. 1, a first pass line (5) + a photo-N converter (6), and another photoelectric converter (7) connected in series.
), backflow prevention diode (8), second pass line (
9). Two photoelectric conversion devices are connected in series to double the output voltage.

FIG. 1(D) is completed by selectively forming a conductor to become a part of the second electrode on the upper side of FIG. 1(C). In the drawing, light (10) was incident on the substrate (1) from above. A first pass line (16) provided in close proximity to the substrate
and the first electrode (13) of the photoelectric conversion device (6) are connected by a lead (17). In addition, the second electrode, the counter electrode (referring to the troublesome electrode that is irradiated with light), is overlapped with the transparent electrode (11) and other auxiliary electrodes (30) such as a grid line pattern, a crosshatch pattern, a fishbone pattern, etc. The aim is to reduce the series resistance. This auxiliary electrode (30) for connection is provided at 20% or less, preferably about 5% of the total effective area irradiated with light. This auxiliary electrode (30) extends onto the substrate along the tapered surface around the side of the semiconductor layer (12) and is connected in series to the first electrode of another conversion device (7). The opposing electrode (11°) of this photoelectric conversion device (7) also consists of a transparent electrode (11) and an auxiliary electrode (22).

Furthermore, this transparent electrode (11") and the auxiliary electrode overlap to constitute one electrode of a backflow prevention diode (8). The semiconductor layer (12') of this diode is the same as the semiconductor layer of the converter (7). They are made of the same material. This is clear from the manufacturing process shown in FIG. A backflow prevention diode (8) is provided on the same plane as the photoelectric conversion devices (6) and (7), which prevents the entire system from becoming inoperable when the conversion device is damaged or short-circuited. It is a feature of the present invention that no new process is required to manufacture this diode. Also, the other electrode (13") of this diode is connected to the base metal (15) constituting the second pass line (9). and an electrode (1 day).

Although this figure shows an example in which two converters are connected in series, the features of the present invention can be further utilized by creating a plurality of converters on the same board and connecting them in series or in parallel. Further, in the present invention, two electrodes having different heights sandwiching a semiconductor layer are connected to each other in the same plane configuration without introducing any new process. This is important for the production of industrially very simple and low cost devices.

FIG. 2 shows another embodiment of the invention. The light passes through the substrate side and is irradiated onto the semiconductor layer from below.

In FIG. 2(A), there is an electrode (37) on the substrate (1) that is part of the first electrode and constitutes part of the counter electrode.
37') (37") was selectively formed using the first mask (2). Furthermore, a transparent electrode (4) and a semiconductor layer (3) were formed on the upper surface in the same manner as in the example shown in FIG. 2(B) was obtained. In FIG. 2(C), a second electrode (34) was formed on the upper surface.

(34') (34'') is formed using the second mask ■, and then the semiconductor layer (3) is formed using this second electrode as a mask.
was selectively etched, and then the transparent electrode (4) was further etched. Therefore, in this example as well, a self-line configuration in which the semiconductor layer and the transparent electrode had approximately the same shape could be achieved. Similarly to FIG. 1, the periphery of the semiconductor N(3) was made into a tapered shape to eliminate disconnections in the wiring.

FIG. 2(D) is a completed diagram of the device of the present invention. The first pass line (5) and the second pass line (9) are provided on the transparent insulating substrate (1), and the photoelectric conversion devices (6) and (7)
generates a photovoltaic force in response to light irradiation through the substrate.

A backflow prevention diode is provided at (8). The area around the (12) (12') side of the semiconductor is an insulator (35) (
35”), and the leads (36”
) (36") to electrically connect the photoelectric conversion devices. Opposing electrodes include transparent electrodes (11) (11') and auxiliary electrodes (37) (37") such as lattice line patterns and cross line patterns. ') (37'') (37). In this case, the substrate material used is a light-transmitting material, typically glass or transparent organic resin.

Examples of the present invention will be shown below based on more specific numbers.

Specific example 1 2 is a longitudinal cross-sectional view of the photoelectric conversion device shown in FIG. 1. FIG.

Glass (thickness: 1.4 mm) was used as the substrate. Furthermore, chromium was formed on the upper surface for a first electrode to a thickness of 2000 mm by electron beam evaporation. Etching was performed using a chrome etch solution.

Thereafter, a non-single crystal semiconductor having a PIN junction was laminated on this upper surface. That is, N-type non-single crystal semiconductor (pH3/5i1
14=0.01, thickness 200 people, Eg 1.7eV),
I-type non-single crystal semiconductor (Si84 100%, thickness 0.5
μ, Eg 1.8eV) Silicon doped with P-type carbon (
C! I4: 5tHn= 1: IBz116/5i
l14=0.003, thickness 100 people, Eg 2.1e
V). These are processed using the glow discharge method (frequency 13.56
MHz.

Output 10W, pressure 0.1 torr, film growth rate 2.1
people/second.

The substrate temperature was 210°C). Furthermore, a transparent conductive film was formed by applying tin oxide to a thickness of 700 mm by electron beam evaporation.
Formed as a person. Plasma etching was performed on the transparent electrode using gas CF, frequency 13.56 M11z, and etching temperature room temperature. Also, semiconductors use gas CF4.
+02 (5%) The etching was performed at a frequency of 13.56 MHz and an etching temperature of room temperature.

Furthermore, the auxiliary electrodes (30) and (22) shown in FIG. 1(B) were fabricated by aluminum vacuum evaporation using a stainless steel mask.

The properties obtained are as follows.

Open circuit voltage 0.7V (2 stages in series) Short circuit current 23μA Fill factor 0.5 Irradiation light White fluorescent lamp 300lx Cell area
10mm x 15mm anti-reverse diode area
In the above description, the transparent electrode was made by doping SnO□ with indium, antimony, or tellurium. However, the electrode on the counter electrode side may be a Schottky electrode or may be an extremely thin insulating film of 20 to 50 layers for forming a Schottky diode.

In this Schottky electrode, a metal with a large work function such as platinum is used instead of a transparent electrode, which is thin enough to allow light to pass through.
It was formed to a thickness of 25 to 100 people.

In addition, in MIS type photoelectric conversion devices, an insulating film is thin enough to allow the tunneling current of 20 to 50 people to flow (11).
A counter auxiliary electrode (22) is provided on which a grid-like or other metal electrode is provided, for example, as shown in FIG. 1(D).
Needless to say, it would be better to set it as .

In the embodiments of the present invention, two pass lines were installed on only one surface of the insulating substrate. However, one pass line or a part of two pass lines were formed by using through holes on the insulating substrate. , it goes without saying that it may be formed using the opposite side or the back side. However, in that case, there is a disadvantage that the price becomes high.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal cross-sectional view of a photoelectric conversion device according to the present invention in which light irradiation is performed from above a substrate, and also shows the manufacturing process thereof. FIG. 2 shows a longitudinal cross-sectional view of a photoelectric conversion device according to the present invention in which light is irradiated from below through a substrate, and also shows the manufacturing process thereof. Figure 1

Claims (1)

[Claims] 1. A photovoltaic device having a first electrode provided on an insulating substrate, a non-single crystal semiconductor layer doped with hydrogen or a halogen element that generates a photovoltaic force on the electrode, and a second electrode on the semiconductor. In the semiconductor device in which a plurality of conversion devices are connected in series or in parallel, a transparent electrode covers part or all of the first or second electrode on the side of the semiconductor layer that is irradiated with light. 1. A photoelectric conversion device characterized in that the semiconductor layer and the first or second electrode in each photoelectric conversion device are provided on the substrate with end portions having substantially the same shape.