JPS60200577A - Photoelectric conversion semiconductor device - Google Patents

Abstract

PURPOSE:To improve the visual merchandise value as the entire device by electrically coupling between adjacent elements by forming an opening hole or groove in an active region, and forming a contact in the hole. CONSTITUTION:A nonsingle crystal semiconductor is formed in homogeneous film thickness on the all upper surfaces of an electrode 3 and a groove 16, and the side 17 of the first electrode is exposed without damaging the surface of a film by forming a laser light. Then, the second electrode 5 is formed on the semiconductor 4 by an electron beam depositing method, and the conductive oxide of ITO is ohmically contacted with the side or upper surface 17 of the first conductive film 3. Thereafter, a laser scribing 10 is executed to form a groove at the position of the second cell side 13. The groove 13 is formed by removing the semiconductor thereunder, forming a groove, and electrically isolating between the second electrodes without the first electrode, further light transmission organic resin 28 is coated on the upper surface of the first electrode, and eventually cut at the boundary 70, and forming photoelectric converters.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to composite photoelectric conversion elements or cells (hereinafter simply referred to as cells) on a flexible substrate having an insulating surface. ) can be easily discerned with the naked eye (less than 100μ, preferably 10 to 50μ), with the aim of improving the visual commercial value of the device as a whole.

This invention provides a thin film having an insulating surface, such as an organic resin thin film, on a bendable substrate such as a stainless steel substrate, and a first electrode made of stainless steel, chromium, or a heat-resistant material mainly composed of chromium, on the substrate ↓ having such an insulating surface. The electrode is made of a composite electrode consisting of a reflective metal (hereinafter simply referred to as chromium) thin film, a reflective metal such as aluminum, and a translucent conductive (conductive) dust such as tin oxide on its upper surface. It has been experimentally found that there are conditions under which no damage is caused to the first electrode-formable thin film, for example, the resin cylinder 13, and this fact is utilized to fabricate semiconductor devices, particularly photoelectric conversion devices. It's a serious thing.

For this reason, in the present invention, a first electrode is provided on a substrate of an organic resin thin film (hereinafter referred to as OF) in a cell provided in an active region, and a non-single electrode that generates a photovoltaic force by light irradiation is provided on this electrode. When arranging a plurality of devices consisting of a crystalline semiconductor and a second electrode on the semiconductor in series, electrical connection between adjacent devices is established by opening or opening/aS ( The present invention is characterized in that it has been achieved by providing an opening (hereinafter simply referred to as an opening) and providing a contact using this opening.

2. Description of the Related Art Flexible thin films having an insulating surface have been used as substrates for inexpensive, mass production of photoelectric conversion devices.

For this reason, the present invention is a heat-resistant OF film made of a thin stainless steel film (thickness 50-150μ) that can be stretched by curling or heat treatment and has no shrinkage, and a polyimide resin (which may be opaque) on top of it.
The substrate was made into a flexible substrate that was inexpensive and had good stability.

The present invention provides such an OF and a conductive material having sublimation properties thereon. l
In particular, for conductive oxide films containing metals containing chromium, indium oxide, or tin oxide,
We experimentally investigated the conditions under which the conductive thin film on the leaves could be selectively removed without turning the leaves into trJ when irradiated with laser light. We have found that it is possible to remove only this conductive material for electrodes by optimizing the scanning speed and without irradiating the electrode for several tens of milliseconds or more.

That is, by irradiation with laser light, the leaf has a low thermal conductivity (generally 1 to 7 x 1O-4 Cal / sec /
ca! / °C/cm), so when laser pulses are repeatedly applied to the same position, heat is accumulated in this organic resin,
This heat carbonizes the resin and causes it to be cut. However, if this process is repeated once or several times, the thermal conductivity of this leaf is 1/10 that of a conductive thin film (hereinafter referred to as CF), such as a composite film of chromium or aluminum and CTF. It has been found that only the areas irradiated with laser light can be selectively removed.

Conventionally, PIN junctions based on non-single-crystal semiconductors, especially non-single-crystal silicon including amorphous silicon, have been used.
They were trying to generate photovoltaic force through light irradiation. However, since the upper and lower electrodes of a semiconductor having a bending junction are connected in series, the lower electrode of one cell and the upper electrode of the adjacent cell must be electrically connected at the F outer side J of the active region. In addition, it was a necessary condition that each cell be electrically isolated from each other.

FIG. 1 shows a typical example of a conventional structure.

FIG. 1(A) is a plan view of the photoelectric conversion device (1) viewed from the back with the transparent glass substrate (2) facing downward.

In the drawing, it has an active region (14) that generates photovoltaic force upon irradiation with light, and an inactive region (15) having a connecting portion (12) that connects each cell (11), <13).

As is clear from the correspondence between the longitudinal cross-sectional views taken along lines A-A' and B-B' in FIG. (13) is the transparent conductivity n' of the first electrode on the glass substrate (2) =
(CTF > (3) are separated from each other between each cell. Also, the semiconductors (4) are connected to each other between each cell. Also, in the non-active region, the upper electrode of the cell (13) , 'F side electrode of cell (11) and connection part (6) t(
7) is connected by the contact (18), and this is repeated to connect the five cells in series between the external electrodes (8) and 4 (9).

However, at first glance, this conventional structure appears to have a high manufacturing yield because there is only one semiconductor (4). However, in reality, three types of masks are used (a first mask for patterning the first conductive film, a second mask for forming a non-active region, and a third mask for patterning the second conductive film). However, since the first mask and the third mask are not of the self-line type, mask misalignment is likely to occur.

Due to this deviation (i.e., a deviation of 0.3 to 1 mm is quite natural for a metal mask), the effective area of the cell is reduced by 10 mm.
It was found that there was a substantial reduction of ~20%.

Furthermore, since a mask is used, the isolation region (22), which is the opening between the electrodes in the active region of FIG. If the shift is 2n+m, the distance in the cell (11) will be 8+nm, and the distance in the isolation (2n+m) will be 8+nm.
2) becomes 2.5 mm, which reduces the effective area by nearly 20%. Further, the area occupied by the outer frame (10) of the cell is also 5 to 7%.

For this reason, it has been strongly recommended that the combination of upper and lower electrodes be made into a self-registration region in order to improve its efficiency.

Furthermore, in the conventional example shown in FIG.
5) is provided, and this non-active region covers two parts of the entire substrate.
It accounts for 0-30%. For this reason, process efficiency decreases, and it is not possible to reduce manufacturing costs.

For this reason, it is extremely important to create a photoelectric conversion device that does not have non-active regions.

Furthermore, since the substrate is a glass substrate, it is easy to break due to mechanical stress. For this reason, the thickness of the flexible substrate is 50 mm.
A leaf for providing an insulating surface is formed on a metal thin film with a thickness of ~200μ, achieving low cost and resistance to mechanical damage.

That is, in the present invention, a typical example is shown in FIG.
From the light irradiation (10) surface side, there are open grooves (IIJIO~70μ, typically 20~30μ) (Figure 2 (20)) that are invisible to the naked eye and are used to separate the plurality of second electrodes. Only. Further, there is no non-active region such as the region (15) in FIG. 1(A), and the connecting portion constitutes the isolation region of each cell. In addition, it is a maskless process that uses LS and simply scans the laser beam in a straight line. Therefore, it has become possible to adopt a so-called computer-aided self-registration method in which the first groove is formed using a television monitor and patterning is performed optically at a predetermined position using the first groove as a reference. .

Further, the contact at the connecting portion between the first electrode of the first cell and the second electrode of the second cell is located inside the semiconductor of the substrate.
The contact is provided at the center (in FIG. 2), and its position is completely different from that of the conventional contact on the outside of the semiconductor.

Furthermore, this internal contact can reduce the series resistance of the transparent conductive film applied to the photoelectric conversion device. As a result,
By not providing the connecting portion outside the cell, it was possible to significantly improve the efficiency of its effective area.

Furthermore, rather than creating an opening with a structure in which all the semiconductor between cells is cut off, one or more open grooves (20 to 90μφ) are discontinuously formed into a circular or elliptical shape ( (In other words, the ends of this open groove are continuous with the semiconductors that make up each cell.)
As a result, this opening can be practically seen with the naked eye.
Another feature of the product is that the scribe line does not become an eyesore.

In addition, since the contact is an open hole, all the side surfaces around the hole can form the contact of the connecting part between the first electrode and the second electrode, and the contact resistance at this part can be kept below 3Ω. I was able to lower it to

The present invention has many such features, and the details thereof will be described below with reference to the drawings.

FIG. 2 shows the manufacturing process and apparatus of the photoelectric conversion device of the present invention.

In the drawing, a stainless steel thin film (2'
) on top of polyimide resin or +145 (Sumilite, type of Sumilite Co., Ltd.) (continuous use temperature 150-300℃)
, thermal conductivity 3-7 Xl0) Cal /sec /c
rA/'C/cm) (two pieces are formed to a thickness of 1 to lOμ, and then a substrate (2) having an insulating surface (for example, thickness 100μ, length in the horizontal direction in the drawing) 60cm, 1
1120cm).

Chromium (thickness: 2000 mm), which is a metal with heat resistance and sublimation property, or aluminum (thickness: 1000 mm), which is a reflective metal, is coated on this needle by electron beam evaporation or magneto sputtering. On top of that, Sn is applied by sputtering method.
A known conductive thin film was used. The sort resistance then had 3.5 Ω/port.

This drawing shows a case where four cells are connected in series.

That is, the photoelectric conversion device of the present invention has a larger 20 to 2000 active regions (14) on the same substrate.
A cm x 60 cm (7) substrate was used.

In each cell, a first conductive film was formed over the entire surface of the base. Furthermore, this conductive film is shaped into a predetermined shape (here, 1.06
A first opening (16) was formed by scribing (YAG laser) with a wavelength of .mu. or 0.53 .mu. according to a vacuum stored and controlled by a microcomputer.

Furthermore, in order to eliminate leakage outside the cell, separation grooves (2G>, (26'>) were formed. Then, the cell area (11 people (13)) and the external connection electrode part (8>, <
9) was formed.

That is, a YAG laser (emission wavelength 0.53μ, focal length 50mm, light (¥20μ) was irradiated here.The conditions were to repeatedly and simultaneously (iKllz, average output 0.2
W, scan speed (scan speed, hereinafter referred to as SS)
The speed was set at 30 cm/min.

Opening formed by scribing? T! 1 (16) had a width of about 25 μm, a length of 20 cm (1 cm in the drawing), and a depth where each first electrode on the needle was completely cut and separated.

The diameter of the first element (11) and the second element (13) was 10 mm.

At this time, when examined using an electron microscope, no tn scratches or local deterioration were observed on the ridge surface. Although this laser beam is estimated to have a temperature of 1,600°C or higher, it did not cause any damage to the leaf, which has a low heat resistance with an upper limit for continuous use of about 180°C.

In other words, it was found that the open groove (16) could be selectively created for the CF on 01+. Moreover, there is a resistance of IMΩ or more between the two probes (the inside is 1cm).
I was able to get

FIG. 3 shows the electrical resistance when an open groove is formed, with the repetition frequency of the laser beam changed to aJ.

In the M plane, a YAG (wavelength: 0.53 μm) laser with a scanning speed of 30 cm/min and an average output of 0.21 and a light diameter of 25 μm was used. Then, when the frequency is lowered from ]υold 1z, the curve (45) becomes I discontinuously below 7Kllz.
It was found that it became possible to electrically isolate the resistance at MΩ or more (45').

However, when this frequency was 4KIIzE, in addition to this CF, the underlying OF was also damaged at its center (the region where the energy density of the Gaussian distribution was highest).

As a result, the range shown in (44) was passed through the LS (laser scribe) of the CF on the needle.

Furthermore, when we investigated the area where only the conductive thin film was removed without applying IA, we found that the fourth
I got the diagram.

That is, the SS is 0 to 120 cmZ, the average output is 0 to 0.5
Assuming a YAG laser with tV, repetition frequency 6KIIz, wavelength 0253μ, and laser beam directivity ¥21μ, the region (49), that is, the range surrounded by points A, B, C, D, E, and F, is a metal without damage to the OF. It was possible to selectively remove part or all of the thin film (CF) containing the CF.

Further, the area (47) is an area in which the thin film shift of the tobacco cannot be removed, and in the area (46), the pulsed light is not continuous above 01. Furthermore, a large amount of residue remains in the area. Area (48) was an area where damage was caused not only to the C'TF but also to the underlying leaf.

This revealed that there is a region (19) where only the CF can be selectively removed as an open groove without damaging the underlying OF.

A plan view of FIG. 2(A) and longitudinal sectional views along lines AA' and FF'' are shown in (A-IO(A-2)), respectively.

Next, as shown in the plan view of Fig. 2 (B), a non-single crystal semiconductor doped with hydrogen or fluorine that generates photovoltaic force by light friction is connected to all electrodes (3) and (16). A uniform film thickness is formed on the upper surface of the film.

This semiconductor (4) is, for example, 5ixC+-x (0<X
< 1 In general, the P type with x = 0.7 to 0.8) is about 1
A semiconductor whose main component is silicon to which type 1 hydrogen or halogen element is added is 0.4 to 0.50 mm thick.
In addition to the 8μ thickness, N-type microcrystalline silicon or N
SixC1-x (0< x < 1 x ~ 0.
9) was used as a gate-N junction structure of a semiconductor whose main component is P (SixC1-x x=0.7~0.
8) I (Si)-N (, UCSi) P (
SixC+-x x=0.7~0.8 )-I (Si
xGel-XX=0.6~0.8)-N(
Microcrystallization (iisi or 5ixC1-XO<x<1
) may be a tandem structure of the own NPIN structure.

Furthermore, a second aperture (15) is formed using a laser beam,
Vertical cross-sectional views of lines BB', (, -C' in FIG. 2(B) are shown corresponding to (B-1) and (B-2).

Thus, the second clarification (■5) exposed the side surface (17) of the first electrode without causing any scratches on the surface of the leaf.

At this time, the two ends of the conductive thin film were exposed with an I of 0 to 5 μm, so that the side and top surfaces of the conductive thin film (3) formed contacts of the connecting portion. Furthermore, if the output is reduced, only silicon can be removed because the wavelength of 0.53 μ of the laser beam has a high absorption coefficient of silicon. In this case, the contact can be made on the top surface.

The conditions for forming the second opening (15) are the same as the conditions for forming the first opening groove, except that pulses of laser light are discontinuously applied only to the position (15). For now, the presence of the semiconductor can be virtually ignored, and the characteristics shown in FIGS. 3 and 4 can be used.

Next, the pattern shown in FIG. 2(C) was formed. Figure 2 (C
) are shown in (C-2), (C-3>, <C-1).

That is, a second electrode is formed on the semiconductor (4) by electron beam evaporation using ITO by 400 to 1,000 people, for example, 700 people.
! J: It was made to form.

Then, the conductive oxide of ITO came into contact with the side surface or top surface (17) of the first conductive film (3) at the opening (15), making ohmic contact possible.

This contact is easily oxidized to form an insulating film as a compound constituting the first electrode. If only aluminum was used, alumina would be formed in the contact portion during long-term use, resulting in a contact resistance of 30Ω or more, which was undesirable. For this reason, when aluminum is used, an oxide such as tin oxide or ITO is always required on its upper surface. Therefore, since the contact is formed by using ITO, which forms the second electrode, as an oxide, the contact resistance is 30 or less and does not change during long-term use, which is preferable. In yet another structure, the first electrode was made of heat-resistant chromium, stainless steel, or other gold mud that does not contain oxide insulators.

In particular, chromium was preferable for laser processing because it has low contact resistance and excellent laser processability.

Furthermore, since the second electrode was made only of ITO, the laser light was transmitted through it, and the third groove substantially scribed the ITO and the semiconductor underneath.

After this, the laser scribe (19
) was carried out. This is a YAG laser (tgL length 0.53
While monitoring the first groove (μ) on a television monitor, an open groove was created at a position 50 to 200μ deeper into the second cell side (13). Average output of laser light 0.1
~0. Q-switched laser beams with a beam diameter of 10 to 30 μΦ, a beam scanning speed of 0.1 = 1 m/min, generally 0.3 m/m, and a wavelength of 0.6 μ or less, that is, 0.53 μ, are particularly effective. It was excellent.

In this way, Si (semiconductor with a thickness of 0.5μ or more to which hydrogen or halogen elements are added) is inherently sublimable and has a large absorption coefficient at a wavelength of 0.53μ, so it can be rapidly heated by laser light. , semiconductor and ITO on it
could be vaporized and removed at the same time.

Thus, in the connecting part (12), the first electrode (23') of the cell (13) and the second electrode (23') of the cell (11)
5) is in ohmic contact with an oxide contact through the second open groove (18). In particular, the contact l-(17) in the connecting part (12) is formed by the side surface or side surface of the first electrode made by the second opening (15) and the upper end surface of the first electrode within 0 to 5μ. This has been accomplished, creating the so-called site contact structure. Immediately, the two cells are electrically connected in series by bringing the abrasive material constituting the second electrode into close contact with this part. I'm letting you do that. (C-1>
, <C-2), the second electrode (5) is simply formed on the semiconductor (4).

The third trench (20) is formed by removing the underlying semiconductor, forming an trench, and then removing the first electrode (20).
It was possible to electrically isolate the second electrodes of each element.

Furthermore, in Fig. ff12 (C), a translucent organic resin (28) is applied to these upper surfaces using a 2P process (a process in which a translucent insulating film is attached using a liquid that is cured by ultraviolet light without raising the temperature). It is completed by coating.

As a result, instead of making one 1 cm x 5 cm photovoltaic device on a needle with an insulating surface on a thin metal film, two
It was possible to fabricate a large number of photoelectric conversion devices at once on a large substrate of 0 cm x 20 cm, 20 cm x 60 cm, or 40 cm x 40 cm.

Finally, these were cut L41iL at the boundary (70) by the method IIi, and each photoelectric conversion device G was cut. For this purpose, instead of creating an active region and a non-active region as in conventionally known photoelectric conversion devices, it is necessary to make the entire active region substantially, and to open the grooves by laser light into α1111
from the end to the end, and set the scanning beam 1' of the laser beam to a large O.
It is important to keep it constant on F. Otherwise, the leaves will be damaged in the parts where the SS is slow.

Open grooves (20), (27), <27' in Figure 2 (C)
) is linearly scanned from α1111 to the end because
This is the time-to-vehicle distance considering productivity. Particularly in areas where the scanning speed at the beginning and end of the laser beam device changes, the energy density applied to the irradiation section becomes unsatisfactory. For this reason, it is necessary to perform ζLS using only a constant speed region, and therefore, forming grooves in a linear manner by S is an extremely important process. Of course, these grooves cannot be seen from the incident light side, so they do not hinder commercial value.

Also, as is clear in Fig. 2 (C), the effective area of the cell is large, except for a very odd part of the connecting part (12) between 10 and 300 μm; It is possible to obtain J area of 92% or more, which is 80% of the conventional example.
%] The structure was much superior.

Taking these things into consideration, it has been found that the present invention has the following major features.

That is, the present invention adopts a method (1) to simultaneously fabricate a large number of photoelectric conversion devices on a large-area substrate with an insulating surface fr, and to divide the photoelectric conversion devices into one photoelectric conversion device on each substrate. It became J-Noh. Therefore, it is possible to manufacture the IJ at a price of 1/3 to 115 that of the conventional method.

[2] Since the first opening groove, the second opening groove, and the third opening groove are self-resisting rain type controlled by a computer, the effective area of the cell is large, and the area between them is made of Hanochi. There is little variation between each photoelectric conversion device [3]
Because it is a maskless process using linear scanning LS,
The manufacturing yield is low [4] The inside of the scribe line of the first and third opening grooves for separation between each cell is extremely small at 10 to 70μ, and the second opening ('L is also extremely small at 10 to 50μψ, In addition, the first groove is not clearly visible from the light irradiation surface side.As a result, it can be confirmed with the naked eye that hybridization has been performed. did it.

In FIG. 2, only one second opening 15) is present inside the semiconductor, particularly near the center. However, even if a plurality of holes (2 to 4 holes) are formed in a broken line or elliptical structure between the first and third grooves in the Y direction, or in a comb-shaped semiconductor (3 holes) ) inside the first open groove (16)
It may be formed along the

The above description is not limited to the pattern of FIG. 2 of the present invention. The number and size of cells are determined by the A1 specifications. Further, for the semiconductor, a plasma CVD method, a low pressure CVD method, a photo CVD method, or a photo plasma CVD method was used.

Applications are possible not only to PIN junctions, heterojunctions, and Kundem junctions, but also to many structures whose main component is non-single-crystal silicon.

Note that the present invention shows a slightly integrated structure on an organic resin. However, in the present invention, an insulating film of silicon nitride, silicon oxide, chromium oxide, etc. is formed on a thin metal layer to a thickness of 300 to 3,000 mm as a barrier 1-, or the substrate itself has an insulating surface (which may be non-transparent). ), and it goes without saying that a conductive thin film for the first electrode may be formed thereon.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional photoelectric conversion device. FIG. 2 shows a plan view and a longitudinal sectional view of the photoelectric conversion device of the present invention according to the manufacturing process. FIG. 3 shows the change in electrical resistance caused by laser scribing when the conductive thin film on the organic resin on the stainless steel base of the present invention was laser scribed. FIG. 4 shows that a conductive thin film is provided on the surface of the organic resin of the present invention,
The area where laser scribing is possible when this thin film is fly-fried with a laser is shown. Patent applicant//side 2M

Claims (1)

[Claims] (1) A plurality of first electrodes arranged on a substrate having an insulating surface, a photovoltaic force generated by light irradiation provided on the first electrodes and the grooves between the electrodes. non-single crystal semiconductor,
and iii) a plurality of photoelectric conversion elements having a plurality of second electrodes provided on the semiconductor in correspondence with the first electrode, and the first and second electrodes of adjacent elements are 1. A photoelectric conversion semiconductor device comprising a connecting portion electrically connected in series by an opening or a groove provided inside a non-single crystal semiconductor. 2. A plurality of first electrodes consisting of reflective metal electrodes arranged on a substrate having an insulating surface and an oxide conductive film on the electrodes, on the first electrodes and the grooves between the electrodes; a plurality of second electrodes comprising a non-single crystal semiconductor that generates a photovoltaic force when irradiated with light; and a transparent oxide conductive film provided on the semiconductor in correspondence with the first electrode; The first and second electrodes of adjacent elements are electrically connected to each other by oxide conductive films through openings or grooves provided inside the non-single crystal semiconductor. A photoelectric conversion semiconductor device characterized by having a connecting portion connected to. 3. In claim 1 or 2, the connecting portion has an opening or an opening provided in the non-single crystal semiconductor and a surface of the insulator under the opening or opening is exposed and has approximately the same shape. a hole or groove is provided in the first conductive electrode, and the conductive oxide material constituting the second electrode is in close contact with the upper part, the side part, or the side part and the upper part of the first electrode. A photoelectric conversion semiconductor device characterized by being provided.