JPH0261158B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention comprises a flexible insulating substrate provided with two bus lines, and a semiconductor layer sandwiched between two electrodes to generate a photovoltaic force. The method relates to providing the above two electrodes with corresponding polarity and connecting them to two bus lines. Specifically, transparent electrodes are provided on both sides of the semiconductor layer where light is irradiated, and the transparent electrodes are connected to each other with corresponding polarity. and the semiconductor layer have approximately the same shape, and furthermore, there is a counter layer on the electrode to electrically connect the electrode and one of the bus lines, and to further reduce the sheet resistance on the transparent electrode side. This relates to a photoelectric conversion device in which an electrode with a grid line pattern, crosshatch pattern, fishbone pattern, etc. is provided as part of the electrode in an area that occupies less than 20% of the area of the transparent electrode, and the photoelectric conversion device is incorporated into the system. The present invention relates to a photoelectric conversion device that reduces the total cost and allows easy extraction of solar energy even when an amateur performs wiring work for the device of the present invention.

[Prior art and its problems]

In order to configure a photoelectric conversion device as a cheaper and more reliable system, the following are required: (1) the first and second electrodes, (2) the semiconductor layer that generates photovoltaic force, and (3) the mechanical aspects of the device. (4) A terminal for electrical connection to the outside, (5) Various mechanical adhesion properties of the terminal to the substrate, (6) One of the two electrodes is optically transparent. (7) The first and second electrodes and the semiconductor layer must be guaranteed against mechanical distortion; (8) The semiconductor layer must have high photoelectric conversion efficiency. .

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

However, in conventional photoelectric conversion devices, the semiconductor that generates photovoltaic force itself is expensive, and
There was no consideration given to the system as a system including the attached equipment.

Previously, for example, attempts were made to create solar cells using current CZ (Czyochoralski) slices.
Assuming 10KW/year and 8000 tons/year of silicon raw material, the cost is 4160 yen per 1W.
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, there are many difficulties in reducing this price from 4,160 yen/W to 40 yen/W, which is 1/100th of that price.
For example, the wafer used for the cell portion has the precision of a substrate with 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 μm, 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 1/W from 3070 Yen/W.
Even if it were possible to reduce the cost to 30 yen/W for 100, it would have cost more than ever to make it modular.

[Purpose of the invention]

The present invention aims to eliminate such drawbacks and form a matrix of a plurality of semiconductor layers on an insulating substrate at a low cost. Furthermore, by making the substrate a flexible substrate, continuous production is possible. It is also intended to make it possible.

[Summary of the invention]

In order to achieve the above object, a plurality of photoelectric conversion devices each include a substrate-side electrode provided on an insulating substrate, a non-single crystal semiconductor on the substrate-side electrode, and an electrode on the non-single-crystal semiconductor, Either or both of the substrate-side electrode and the electrode on the non-single crystal semiconductor cover a metal auxiliary electrode having a lattice line pattern, a crosshatch pattern, a fishbone pattern, etc., and at least a part of the auxiliary electrode. A photoelectric conversion device comprising a single crystal semiconductor and a transparent conductive film provided in close contact with each other, and each of the plurality of photoelectric conversion devices adjacent to each other is connected to each other via an auxiliary electrode. The structure is as follows.

On the other hand, even if some of the solar cells are damaged or the stage on which multiple silicon slices are assembled,
A backflow prevention diode or the like is required to prevent the solar cells from shooting and losing power due to backflow, but the present invention uses a carrier as a substrate as such a system and generates photovoltaic power on the upper side. The same semiconductor layer as the semiconductor layer is used as a backflow prevention diode, and in addition, this substrate is used as a substrate that guarantees mechanical distortion of the semiconductor layer.In addition, an external lead-out end is also attached, and positive and negative voltages are provided on this substrate. At least two bus lines are provided, and the bus lines are used to form multiple semiconductor layers into a matrix to unify the entire system.Continuous production is also possible by using a bendable substrate. It is characterized by being made possible.

In addition, the present invention uses etching or photoetching or selective printing for such low-cost manufacturing, and can be completed in 3 to 4 mask steps, and in particular, the semiconductor layer and the first or second electrode. The manufacturing process is simplified by making one transparent electrode approximately the same shape, and furthermore, the present invention provides a lead leading to the substrate from the electrode provided above the substrate surface along the side surface of the semiconductor layer. It has the following characteristics.

〔Example〕

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 is a conductive electrode 2 on an insulating substrate 1.
are selectively formed. If a photoetching process is used, a second photomask is used. However, selective plasma etching or printing methods may be used to simplify and reduce costs.

Substrate materials include polyimide, polyester,
Silicone resin etc. were used.

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 polyimide substrate and aluminum is further formed on the upper surface.

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

The semiconductor layer was a PIN junction and was fabricated so that 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 perform light-to-electrical conversion. In other words, increase Eg on the light irradiation side, that is, 2 to 3 eV of W-Eg (WIDE Eg), and reduce Eg on the opposite side, that is, N-Eg (NALLOW Eg).
The voltage was set to 0.7 to 1.5 eV. As a semiconductor material, silicon is the main component, and C, N, O, Ge, Sn,
Pb, In, Sb, and Te were added as necessary. Furthermore, the semiconductor layer was mainly formed using a low pressure CVD method or a glow discharge method. For these, patent applications and Japanese patent applications No. 53-086867/
086868 (Japanese Unexamined Patent Publication No. 13938/13937)
54-032070/032071 (Unexamined Japanese Patent Publication No. 1983-124275/124272
No. 49-071738 (Japanese Unexamined Patent Publication No. 51-890).

Thereafter, as shown in FIG. 1C, unnecessary portions of the semiconductor layer 121 and the transparent conductive electrode 111 were removed by a second etching process using the same mask. As a result of this etching, the semiconductor layer 1 is formed into approximately the same shape as the patterns 111 and 112 of the transparent electrodes.
21,122 were 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. Actually, fluorine-based plasma etchant was used. That is, in a plasma etching apparatus having parallel plate type electrodes, a metal mask is used as a transparent electrode, and a portion 11 where a semiconductor layer is left is used.
1, 112, 121, and 122, and selectively caused plasma discharge only in the portions to be removed. At this time, a plasma discharge was caused between a common electrode under the substrate and a positive counter electrode located slightly apart from the substrate transparent electrode on the substrate. 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 + counter electrode is periodically vibrated and moved up and down or left and right and back and forth in a width of 1 mm to 1 cm at a speed of 1 to 10 c/s, 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 is approximately 45° relative to the substrate when the etch rate is the same, and the angle of the taper is approximately 45° relative to the substrate when the etch rate is the same as the etch rate.
When doubled, it was possible to create a bevel shape of approximately 30°.

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

In FIG. 1, a first bus line 5, a photoelectric conversion device 6, another photoelectric conversion device 7 connected in series, a backflow prevention diode 8, and a second bus line 9 are provided. Two photoelectric conversion devices are connected in series to double the output voltage.

FIG. 1D is completed by selectively forming a conductor that will become a part of the second electrode on the upper side of C.
In the drawing, the light 10 is incident on the substrate 1 from above. A base metal 15 constituting the first bus line 5 provided closely to the substrate and a first electrode 131 of the photoelectric conversion device 6 are connected by a lead 17. In addition, the counter electrode (the electrode on the side where light is irradiated) which is the second electrode is the transparent conductive electrode 11.
1 and other auxiliary electrodes 30 such as a lattice line pattern, a crosshatch pattern, a fishbone pattern, etc. to reduce the series resistance. This auxiliary electrode 30 for connection is 20% of the total effective area irradiated with light.
% or less, preferably about 5%. This auxiliary electrode 30 extends onto the substrate along the tapered surface around the side of the semiconductor layer 121 and is connected in series to the first electrode of another conversion device 7 . The transparent conductive electrode 112 of this photoelectric conversion device 7 also consists of a transparent conductive electrode 111 and an auxiliary electrode 22.

Further, the transparent conductive electrode 112 and the auxiliary electrode overlap to constitute one electrode of the backflow prevention diode 8. Semiconductor layer 12 of this diode
2 is made of the same material as the semiconductor layer of the photoelectric conversion device 7. This is clear from the manufacturing process shown in FIG. 1B, which was obtained by selectively etching the same semiconductor layer 3. That is, on the same insulating substrate, 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 shot due to damage or the like. A feature of the present invention is that no new process is required to manufacture this diode. Further, this diode-side electrode 14 constitutes an electrode on a base metal 15 constituting the second bus line 9 with the electrode 14 as a lead.

Although this drawing 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 arranging them in series or in parallel. Furthermore, the present invention connects two electrodes sandwiching a semiconductor layer and having different heights in the same plane 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 board and the numbers of each part are the same as in the embodiment shown in FIG. This example is also a case where light is irradiated from above.

In FIG. 1, the leads from the counter electrodes were in close contact with the side surfaces of the semiconductor layers 121, 121 and extended onto the substrate. That is, in this case, the lengths 281 and 282 of the contact portions in FIG. It is necessary that the size be large enough. In other words, when the thickness of the semiconductor layer is 1 to 3 μm, the thickness
It requires 3 mm to 3 cm, which is 10 ² to 10 ⁴ times. Therefore, in order to avoid wasting this area, the periphery of the side of the semiconductor layer having the junction portion was covered with an insulating material, although it added one step. In FIG. 2, insulators 331, 332, and 333 are interposed between the leads and the semiconductor to provide electrical insulation and stability. The reliability of the semiconductor layer is improved because the bonding portion is covered with an insulator, but it has the disadvantage of requiring a new step of selectively coating the insulator. This insulator also constitutes a mechanical protection layer 20 for the converter devices 6,7.

FIG. 3 shows another embodiment of the invention. Light passes through the substrate side and is irradiated onto the semiconductor layer from below.
In the drawing, an electrode A is formed on the substrate 1, and is a first electrode and also constitutes a part of the counter electrode. Furthermore, a transparent electrode 4 and a semiconductor layer 3 are formed on the upper surface in the same manner as in FIG. Furthermore, after forming second electrodes 341, 342, and 343 on top of the semiconductor layer 3, the semiconductor layer 3 was selectively etched using the second electrodes as a mask, and the transparent electrode 4 was further etched. Therefore, in this example as well, a self-aligned structure 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 layer 3 was tapered to remove disconnections in the wiring.

D is a completed diagram of the photoelectric conversion device of the present invention. The first bus line 5 and the second bus line 9 are provided on an insulating substrate, and the conversion devices 6 and 7 generate a photovoltaic force in response to light irradiation through the substrate. A backflow prevention diode is provided at 8. 12 of the semiconductor layer
The periphery of the 1,122 side is surrounded by insulators 352, 353, and the leads 361, 36 on this insulator
2 electrically connects the two devices. The opposing electrodes include transparent electrodes 111, 112, a grid line pattern, a cross line pattern, etc.
1,372,373,374.

FIG. 4 shows the relationship between the bus line and external connection terminals in the present invention.

In A, a base metal 15 and a metal lead 18 are provided on the upper surface of the base metal 15 on a substrate 1, and a wire 41 having a diameter of 100 to 200 μm is bonded 40 to the base metal 15.
B and C are 0.2~1mm wire 41 soldered 4
7, and in particular B is secured by a resin coating 42 after soldering. In D, only a portion of the resin coating 42 is selectively removed and the wire 41 is ultrasonically bonded. A hole E is made in the board, a bolt 44 is fixed thereon, and two nuts 451 and 452 are used to extract a larger amount of power to the outside. The converter section is protected by 42.

FIG. 5A shows four photoelectric conversion devices arranged in parallel and has a square shape with sides of 10 to 100 cm. In addition, Fig. 5B shows two devices arranged in series,
Furthermore, they are arranged in two parallel arrays. FIG. 5B has two bus lines 50, 51, which are provided on a substrate 59. Backflow prevention diodes are provided at 531, 532, and 54, and one diodes 531, 532 may be provided in each device, and one diodes 54 may be provided in this system. In either case, when one device or one series becomes short due to destruction or the like, the purpose is to prevent the electric potential from lowering and the current from flowing backwards. Furthermore, the backflow prevention diode is connected to the external connection terminal 5, which is the output terminal, when the system is no longer irradiated with light, such as at night.
The potential of 6 and 57 may be higher than the potential of the converter or system, causing current to flow backwards, but this is intended to prevent such a situation.

One of the features of the present invention is that this backflow prevention diode is formed on the substrate at the same time as the photoelectric conversion device.
Moreover, as is clear from FIGS. 1 to 5, when considering the current density of this diode, it is sufficient to use one tenth or less of that of the photoelectric conversion device. Even if the area occupied on the substrate was 1/50 to 1/100, it was sufficient. In order to improve the reverse breakdown voltage of the diode and to prevent soft breakdown of the diode, it is extremely important to form a bevel around the side of the diode.

In the above description, the transparent electrode was fabricated by doping SnO ₂ with indium, antimony, or tellurium. However, the electrode on the counter electrode side may be a shot electrode or an extremely thin insulating film with a thickness of 20 to 50 Å for forming a shot diode.

In this shotgun electrode, instead of a transparent electrode, a metal with a high work function, such as platinum, was formed to a thickness of 25 to 100 Å and thin enough to allow light to pass through.

In addition, in MIS type photoelectric conversion devices, 20 to 50
It goes without saying that an insulating film thin enough to allow a tunnel current of 1.5 Å to flow may be provided corresponding to 11, and a lattice-shaped or other metal electrode may be provided thereon as a counter electrode, for example, as shown in FIG. 1 D22. do not have.

In the embodiment of the present invention, at least two bus lines are provided on only one surface of the insulating substrate. However, it goes without saying that one bus line or a portion of two bus lines may be formed by using through holes in the insulating substrate and using the opposite or back surface thereof.

The present invention is characterized in that one of the two bus lines is electrically connected to a second electrode located at a distance from the surface of the substrate by a semiconductor layer, and a special process is performed for the connection. The reason is that it is treated as if it were the first electrode without requiring it. That is, the side surfaces of the semiconductor layer are tapered, the transparent electrode and the semiconductor have a self-aligned structure, and so on, so that they can be handled on the same surface.

〔Effect of the invention〕

According to the photoelectric conversion device of the present invention, multiple semiconductor layers can be easily and inexpensively connected on the same substrate, and a backflow prevention diode can also be formed at the same time, so a systemized photoelectric conversion device can be created. can do. Further, since the insulating substrate is made flexible, mass production of the systemized photoelectric conversion device described above becomes possible by continuous production by winding the flexible substrate such as a polymer film into a roll.

[Brief explanation of drawings]

FIGS. 1 and 2 show a longitudinal section of a photoelectric conversion device according to the present invention in which light irradiation is performed from above, and also show the manufacturing process thereof. FIG. 3 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. FIG. 4 is an embodiment showing the relationship between the substrate, bus lines, and external connection terminals of the present invention.
FIG. 5 shows a photoelectric conversion device when used as a stack or a system. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Conductive electrode, 3... Semiconductor layer, 4... Second electrode material, 5... First bus line, 6, 7... Photoelectric conversion device, 8... Backflow Prevention diode, 9...Second bus line, 10...
...Light, 111,112,113...Transparent conductive electrode, 121,122,123...Semiconductor layer, 13
...First electrode.

Claims (1)

[Scope of Claims] 1. A plurality of photoelectric conversion devices having a substrate-side electrode provided on an insulating substrate, a non-single crystal semiconductor on the substrate-side electrode, and an electrode on the non-single-crystal semiconductor, Either or both of the substrate-side electrode and the electrode on the non-single crystal semiconductor cover a metal auxiliary electrode having a lattice line pattern, a crosshatch pattern, a fishbone pattern, etc., and at least a part of the auxiliary electrode. A plurality of photoelectric conversion devices constituted by a single crystal semiconductor and a transparent conductive film provided in close contact with each other, and a backflow prevention diode constituted by the same non-single crystal semiconductor as the photoelectric conversion devices are provided. . A photoelectric conversion device, wherein adjacent photoelectric conversion devices of the plurality of photoelectric conversion devices are each connected via the auxiliary electrode. 2. The photoelectric conversion device according to claim 1, wherein the plurality of photoelectric conversion devices on the insulating substrate are each connected in series or in parallel.