JPH065775B2 - Photoelectric conversion semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a non-single crystal semiconductor including an amorphous semiconductor having at least one junction capable of generating a photoelectromotive force upon irradiation with light, on an insulating substrate. The present invention relates to a photoelectric conversion semiconductor device in which a plurality of photoelectric conversion elements are electrically connected in series and which can generate a high voltage.

[Conventional technology and its problems]

Conventionally, many examples of a photoelectric conversion device, that is, a device in which a plurality of elements are arranged on the same substrate and integrated, arrayed or compounded, are well known.

For example, non-single-crystal semiconductors, especially non-single-crystal PIN junctions containing amorphous silicon, are used to generate photoelectromotive force by light irradiation, but electrodes are connected in series above and below semiconductors with such junctions. In order to achieve this, the electrical connection between the lower electrode of one cell and the upper electrode of the adjacent cell was made outside the active region, but it is necessary that each cell be electrically isolated from each other. I was trying.

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

FIG. 1 (A) shows a photoelectric conversion device 1 with a translucent glass substrate 2
It is the top view seen from the back which made the lower side. In the figure,
It has an active region 14 and a non-active region 15 which generate photovoltaics by light irradiation.

As shown in FIGS. 1 (B) and 1 (C) corresponding to the longitudinal sectional views of AA ′ and BB ′ in FIG. 1 (A), in the active region 14, in each cell 11, 13 The translucent conductive film 3 forming the first electrode on the glass substrate 2 is separated between the cells. The semiconductor 4 is connected to each other between the cells. In addition, in the inactive region 15, the upper electrode 5 of the cell 13 is connected to the lower electrode of the cell 11 by the contact 18 in the connecting portions 6 and 7, and this is repeated to make five cells of the external electrodes 8 and 9. It is connected in series between.

However, the photoelectric conversion device having the conventional structure seems to have a high manufacturing yield because the semiconductor 4 is one. However, in practice, three types of masks are used: a first mask for patterning the first conductive film, a second mask for forming an inactive region, and a third mask for patterning the second conductive film. Although these masks are used, since the first mask and the third mask are not the self-alignment method, mask shift is likely to occur. This shift (in metal masks
It has been found that the effective area of the cell is substantially reduced by 10 to 20% due to the deviation of 0.3 to 1 mm being quite natural.

Further, since a mask is used, as shown in FIG. 1 (B), the isolation region 22 which is an open groove between the electrodes in the active region 14 has 0.2 to 1 mm, for example, 0.5 mm.
If the cell width is 10 mm and it is shifted by 2 mm, the cell width is 1
1 is 8 mm, the isolation width 22 is 2.5 mm, and the effective area is reduced by 20%. The area occupied by the outer frame 30 of the cell is also 5 to 7%. For this reason, it has been strongly demanded that the combination of the upper and lower electrodes be self-registered in order to improve its efficiency.

Further, in the photoelectric conversion device having the conventional structure, the glass substrate 2 is provided with the inactive region 15, and the inactive region 15 is provided.
Occupies 20 to 30% of the entire substrate. For this reason, the efficiency in the process becomes low, and eventually the manufacturing cost cannot be reduced.

Therefore, it was extremely important to make a photoelectric conversion device in which the non-active region 15 does not exist.

Furthermore, since the substrate is a glass substrate, it is easily damaged by mechanical stress.

In order to improve the drawbacks of the photoelectric conversion device by manufacturing the photoelectric conversion device by mask alignment as described above, a photoelectric conversion device manufactured by using a method for manufacturing a photoelectric conversion device by a laser scribing method has been proposed ( For example,
JP-A-57-12568).

The outline of the photoelectric conversion device by the laser scribing method will be described. (1) A plurality of transparent electrode strips are formed on a transparent substrate made of glass by cutting out laser light in a transparent electrode group.

(2) An active region of semiconductor material is formed on the transparent substrate and the transparent electrode strip.

(3) Adjacent to the first scoring and parallel to it with a laser to form a group of strips of the active area so as not to substantially damage the transparent electrode.

(4) The strips of the active area are connected in series with the back electrode.

The photoelectric conversion device thus manufactured can solve the problems of the photoelectric conversion device manufactured by the mask alignment method.

However, the active area is scribed by a laser adjacent to and parallel to the first scoring to form strips of the active area so as not to substantially damage the transparent electrode, When the strips are connected in series with the back electrode, the material forming the active region has a low sheet resistance, so that the edges of the active region are insulated with a dielectric material before the active regions are connected in series. There is a need.

Further, since glass is used as the substrate, it is easily damaged by mechanical stress.

[Problems to be solved by the invention]

In view of the above problems, the present invention is strong against mechanical stress,
It is intended to provide a photoelectric conversion semiconductor device including a connecting portion that connects active regions in series without separately providing a special insulating material in the active region.

[Means for Solving the Problems]

The present invention provides a plurality of first electrodes arranged on a substrate having an insulating surface in which an insulating organic resin film is provided on a flexible metal thin film, a first electrode, and a laser scribe between the electrodes. A non-single-crystal semiconductor that emits a photoelectromotive force by light irradiation provided on an opening formed by
A plurality of second electrodes provided on the semiconductor corresponding to the electrodes of
A plurality of photoelectric conversion elements each having an electrode, and the first and second electrodes of adjacent elements do not reach an end portion orthogonal to the groove between the first electrodes of the non-single crystal semiconductor. It is characterized in that it has a connecting portion electrically connected in series by the same conductive film as the second electrode filled in the provided hole or groove formed by the laser scribing method.

Furthermore, the present invention provides a reflective metal electrode arranged on a substrate having an insulating surface in which an insulating organic resin film is provided on a flexible metal thin film, and a translucent oxide conductive film on the electrode. A plurality of first electrodes made of, a non-single-crystal semiconductor that generates a photoelectromotive force by light irradiation provided on an opening formed by a laser scribing method between the first electrodes and the electrodes,
And a plurality of photoelectric conversion elements having a plurality of second electrodes made of a translucent oxide conductive film provided on the semiconductor corresponding to the first electrodes, and a first photoelectric conversion element of adjacent elements. And the second electrode is an oxide conductive layer formed by a laser scribing method provided inside the non-single-crystal semiconductor that does not reach the end portion orthogonal to the opening between the first electrodes. It is characterized by having a connecting portion electrically connected by the membranes.

〔Example〕

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

In FIG. 2, an organic resin thin film, for example, a polyimide resin film 2 ″ is formed on a stainless steel thin film 2 ′ having a thickness of 100 μm by 1 to 1.
The substrate 2 having a thickness of 10 μm and having an insulating surface (for example, thickness 100 μm, length 60 cm, width 20) is formed.
cm). It has heat resistance on this organic resin thin film 2 ″ by electron beam evaporation method or magneto sputtering method,
In addition, chromium, which is a sublimable metal, has a thickness of 2000Å or aluminum which is a reflective metal, 1000Å, and SnO having a thickness of 1100Å formed thereon by a sputtering method, and a composite conductive thin film is used. The sheet resistance in this case is 3.5Ω / □
Had.

FIG. 2 shows an example in which four cells are connected in series. That is, in the example of the photoelectric conversion device of the present invention, a larger substrate of 20 cm × 60 cm having 100 to 2000 active regions 14 simultaneously on the same substrate was used.

In each cell, the first conductive film 3 is formed on the entire surface of the substrate 2, and the conductive film 3 is formed into a predetermined shape with a laser such as 1.06 μ or
Laser scribing with a YAG laser having a wavelength of 0.53 μ was performed to form the first open groove 16 according to a pattern stored and controlled by a microcomputer.

Further, in order to remove the leak on the outside of the cell, separation open grooves 26 and 26 'were formed. And the cell area 11,
13 and external connection electrode parts 8 and 9 were formed.

That is, here YAG laser (emission wavelength 0.53μ, focal length 50m
m, light diameter 20 μ). As the conditions, the repetition frequency was 6 kHz, the average output was 0.2 w, and the scanning speed was 30 cm / min.

Open groove 16 formed by the laser scribing
Was formed by completely cutting and separating each first electrode 3 on the organic resin thin film 2 ″ having a width of about 25 μm, a length of 20 cm and a depth.

The width of the first cell 11 and the second cell 13 was 10 mm.

At this time, in the range examined by an electron microscope, no damage or partial deterioration was observed on the surface of the organic resin thin film 2 ″. This laser beam is presumed to have a temperature of 1600 ° C. or higher. However, no damage was given to the organic resin thin film 2 ″, which has a low heat resistance of about 180 ° C. in the continuous use upper limit temperature.

That is, it was found that the open groove 16 can be selectively formed in the conductive thin film on the organic resin thin film 2 ″. Moreover, the resistance of 1 MΩ or more (width is 1 cm and between the two probes). I was able to get it.

FIG. 3 shows a variable repetition frequency of laser light, and shows an electric resistance when an open groove is formed.

In Fig. 3, scanning speed 30 cm / min, average output 0.2
A YAG laser (wavelength 0.53μ) with W and a light diameter of 25μ was used. When the frequency is lowered below 10 KHz, the curve 45 becomes k
It was found that it became possible to electrically perform isolation in the range of 1 MΩ or more and 45 'discontinuously below Hz.

However, at a frequency of 4 kHz or less, in addition to the conductive thin film 2 ', the underlying organic resin thin film 2 "was also damaged in the central portion (the region having the highest energy density of Gaussian distribution).

Therefore, the range shown by 44 is suitable for the laser scribing of the conductive thin film on the organic resin thin film 2 ″. Further, only the conductive thin film is removed without damaging the underlying organic resin thin film 2 ″. When the area to be subjected was investigated, FIG. 4 was obtained.

That is, laser scribing 120 cm / min, repetition frequency 6 kHz, wavelength 0.53 μ, laser light diameter 21 μ Y
If it is an AG laser, the region 49, that is, points A, B, C, D,
In the area surrounded by E and F, the organic resin thin film 2 ″ was not damaged, and the conductive thin film having a metal partially or entirely could be selectively removed.

Further, the region 47 is a region in which even this conductive thin film cannot be removed, and in the region 46, pulsed light is not continuous on the conductive thin film, and a large amount of residue remains in the open groove. The region 48 was a region that damaged not only the conductive thin film but also the underlying organic resin thin film 2 ″.

From this, it was found that there is a region 49 in which only the conductive thin film can be selectively removed as an opening without damaging the underlying organic resin thin film 2 ″.

As shown in FIG. 2 (B-1), the non-single-crystal semiconductor 4 added with hydrogen or fluorine, which generates a photoelectromotive force by light irradiation, is formed in the first electrode 3 and the first groove 16. A uniform film thickness is formed on all upper surfaces.

The semiconductor 4 may be, for example, _Six C _1-x (0 <x <1 generally x = 0.
7-0.8) P-type to a thickness of about 150Å, further hydrogen- or halogen-added silicon-based I-type semiconductors to a thickness of 0.4-0.8μ, and N-type microcrystals. A PIN junction structure of a semiconductor containing silicon or N-type Si _x C _1-x (0 <x <1x to 0.9) as a main component is used. P (Si _x C _1-x
x = 0.7 to 0.8) -I (Si) -N (μCSi) -P (Si _x
C _1-x x = 0.7 to 0.8) -I (Si _x Ge _1-x x = 0.6 to 0.8) -N
A tandem structure of PINPIN structure such as (microcrystallized Si or Si _x C _1-x 0 <x <1) may be used.

Further, the aperture 15 is formed by laser light, and FIG.
2 is a vertical cross-sectional view of BB 'and CC' in FIG.
1) and (B-2).

The opening 15 exposes the side surface 17 of the first electrode 3 without damaging the surface of the organic resin thin film 2 ″.

At this time, as a result of exposing the upper end portion of the conductive thin film with a width of 0 to 5 μm, the side surface and the upper surface of the conductive thin film constituted the contact of the connecting portion. Further, when the laser output is reduced, only the silicon can be removed because the wavelength of 0.53μ of the laser light has a high absorption coefficient of silicon. In this case, the upper surface contact can be used.

The conditions for forming the second opening 15 are as follows.
Is the same as the condition for forming the above, except that the laser light pulse is discontinuously applied only to 15 positions.

That is, the presence of the semiconductor can be ignored substantially, and the characteristics shown in FIGS. 3 and 4 could be used.

Next, the pattern of FIG. 2 (C) was formed. D in Fig. 2 (C)
-D ', EE', GG 'the longitudinal sectional view corresponding to the second
It is shown in FIGS. (C-2), (C-3), and (C-1).

The second electrodes 5, 25 and 25 'were formed on the semiconductor 4 by electron beam evaporation to form ITO with a thickness of 400 to 1000Å, for example 700Å.

Then, in the opening 15, the side surface or the upper surface 17 of the first electrode 3 was brought into contact with the conductive oxide of ITO, and it was possible to make ohmic contact.

In this contact, the conductive thin film 3 forming the first electrode 3 is easily oxidized to form an insulating film. With aluminum alone, alumina was formed at the contact portion during long-term use, and the contact resistance was 30Ω or more, which was not preferable. Therefore, when using aluminum, tin oxide or ITO, which is an oxide, is always required on the upper surface. Therefore, when ITO is used as an oxide for the second electrodes 5, 25, 25 'to form a contact, the contact resistance is 3Ω or less and does not change for long-term use, which is preferable. As another structure, a metal that does not form an oxide insulator such as heat-resistant chromium or stainless is used for the first electrode. In particular, chromium is preferable for laser processing because it has low contact resistance and excellent laser processing property.

When the second electrodes 5, 25, 25 ′ are made of ITO only, the laser beam is transmitted, so that the second trench 20 can substantially form ITO and the semiconductor 4 thereunder by laser scribing. The second groove 20 was formed by laser scribing as shown in FIG. 2 (C). This laser scribing was performed by monitoring the first groove 16 with a YAG laser (wavelength 0.53 μ) on a television monitor. At the same time, the second open groove 20 was formed at a position 50 to 200 μm closer to the second cell 13 side. The average output of laser light is 0.1 to 0.3W, and the beam diameter is 10
.About.30 .mu..phi., Beam scanning speed 0.1 to 1 m / min, generally 0.3 m / min.

For the formation of the second open groove 20, laser light having a wavelength of 0.6 μ or less, that is, a Q3 switch of 0.53 μ, which has an extremely large light irradiation coefficient of a semiconductor, was particularly excellent.

Then, Si (hydrogen or halogen element is added
A semiconductor with a thickness of 0.5μ or more) is essentially sublimable and has a large absorption coefficient at a wavelength of 0.53μ, so the temperature rises faster than the laser light, and the semiconductor and ITO on it are vaporized at the same time. Could be removed.

Thus, in the connecting part 12, the first electrode 23 ′ of the cell 13 and the second electrode 25 of the cell 11 are in ohmic contact with the oxide contact 18 through the opening 15. In particular, the contact portion 17 in the connecting portion 12 has a side surface or an upper surface of the first electrodes 23, 23 ′ formed at the time of forming the opening 15 by the laser scribing method, and the contact portion 17 is 0 to 5.
This is achieved by the upper end faces of the first electrodes 25 and 25 'having a width of μ, and has a so-called side contact structure. That is, the side contact of the second opening 15 of only 10 to 70 μφ is sufficient for the two cells, and the material forming the second electrodes 5, 25, 25 ′ is brought into close contact with this side and electrically connected in series. I'm connecting.

As is apparent from the vertical sectional views of FIGS. 2C-1 and 2C-2, the second electrodes 5, 25 and 25 'are merely formed on the semiconductor 4. Then, the second open groove 2
0 was formed by removing the semiconductor 4 therebelow, and it was possible to electrically isolate the second electrodes of the respective elements without scooping the first electrode 23.

Further, in FIG. 2 (C), a transparent organic resin 28 is coated on these upper surfaces by a 2P process (a process of attaching a transparent insulating film using a liquid that is cured by ultraviolet light without particularly raising the temperature). Complete.

According to the process of the present invention, a 1 cm × 5 cm photoelectric conversion device is formed on an organic resin thin film having an insulating surface on a metal thin film.
20cm × 20cm or 20cm × 40 instead of making one
It has become possible to make a large number of photoelectric conversion devices at one time on a substrate with a size of cm.

And finally, as shown in FIG. 2 (C-3),
Each of the photoelectric conversion devices was cut at the boundary 70 by a cutting method. To this end, instead of forming an active region and an inactive region as in the conventional photoelectric conversion device, all of the active region 14 is substantially formed, and the open groove is formed from end to end by a laser scribing method using laser light. Therefore, it is necessary to keep the scanning speed of the laser light constant on a large organic resin thin film for this purpose. This is because the organic resin thin film is damaged in the portion where the scanning speed is not constant and the laser scribing is slow.

The fact that the open grooves 20, 27, 27 'in FIG. 2C are linearly scanned from end to end is important when considering mass productivity. In particular, the energy density in the irradiation portion becomes large in the region where the scanning speed of the laser beam starts and ends and the scanning speed changes. Therefore, the formation of open grooves by linear laser scribing is an extremely important process. Since these open grooves are not seen from the incident light side at all, they do not interfere with the commercial value.

Also, as is apparent in FIG. 2C, the effective area of the cell is all other than the extremely small portion of the connecting portion 12 having a width of 10 to 300 μm, and the effective area is 90% or more. The structure of the present invention was remarkably excellent as compared with 80% of the conventional example.

In FIG. 2, only one hole 15 exists inside the semiconductor, especially near the center. However, a plurality of holes, for example, 2 to 4 holes are formed in a broken line or elliptical structure in the Y direction. It may be formed between the first open groove 16 and the second open groove 20, or may be formed inside the semiconductor 4 in a comb shape along the first open groove 16.

The above description is not limited to the pattern of FIG. 2 of the embodiment of the present invention. The number and size of cells are determined by their design specifications. For semiconductors, plasma ama CVD
Method, low pressure CVD method, photo CVD method or photo plasma CVD method
You may form using a method.

Further, the present invention is applicable not only to PIN junctions, hetero junctions, and tandem junctions containing non-single crystal silicon as a main component, but also to many structures.

In the above-mentioned embodiment, the structure integrated on the organic resin thin film 2 ″ is shown, but an insulating film such as silicon nitride, silicon oxide or chromium oxide is formed on the metal thin film as a barrier layer with a thickness of 30 to 3000 Å. It is needless to say that the conductive thin film for the first electrode may be formed or the substrate itself may be an insulating surface (may be non-translucent).

[Advantages of the Invention] (1) Since an insulating thin film on a flexible metal thin film, for example, a substrate having an insulating surface provided with an insulating organic resin thin film is used, it is hard to be damaged by mechanical stress and is mechanically resistant. It is possible to realize a photoelectric conversion device that is suitable for preventing damage and reducing costs.

(2) It is possible to adopt a method in which a large number of photoelectric conversion devices are simultaneously formed on a large-area substrate having an insulating surface and the photoelectric conversion devices are divided to form one photoelectric conversion device on each substrate. Therefore, it is possible to manufacture at a price of 1/3 to 1/5 of the conventional price.

(3) Since the first groove, the hole, and the second groove can be formed by the self-registration method by the computer-controlled laser scribing method, the effective area of the cell is large and the process is a maskless process. , The manufacturing yield is high.

(4) The width of the scribe line of the first and second open grooves for cell separation is as small as 10 to 70 μm, and the number of open holes is 10
It is extremely small, about 50 μφ, and the first groove is completely invisible from the light irradiation surface. As a result, it cannot be confirmed with the naked eye that the product is hybridized, and a high pay-per-value product can be provided.

(5) When the connector is made of metal, leakage is likely to occur due to migration, but the present invention uses a conductive oxide for the conductor forming the connector to form the first electrode and the second electrode. Since this is connected, a highly reliable photoelectric conversion device with less leakage at the connecting portion can be obtained.

(6) According to the present invention, since the conductive oxide forming the connector is made of the same oxide as the second electrode of one photoelectric conversion element, the second electrode and the connector can be formed in one step. Since it is adopted, it is not necessary to form a conventional connector such as aluminum in a separate process, migration can be prevented, and an extremely high final yield can be achieved.

Has the effect.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a conventional photoelectric conversion device. FIG. 2 is a diagram showing a plan view and a vertical cross-sectional view of a photoelectric conversion device of the present invention according to a manufacturing process. FIG. 3 is a diagram showing a change in electric resistance due to laser scribing when a conductive thin film on an organic resin on a stainless steel substrate of the present invention is laser scribed. FIG. 4 is a diagram showing a region where laser scribing is possible when a conductive thin film is provided on the surface of the organic resin of the present invention and laser scribing is performed on this thin film.

Claims (2)

[Claims] 1. A plurality of first electrodes arranged on a substrate having an insulating surface in which an insulating organic resin film is provided on a flexible metal thin film, a first electrode, and a laser between the electrodes. A non-single-crystal semiconductor provided on an open groove formed by a scribe method and emitting a photoelectromotive force by light irradiation; and a plurality of second electrodes provided on the semiconductor corresponding to the first electrode. A plurality of photoelectric conversion elements each having the first and second electrodes of adjacent elements are provided inside the non-single-crystal semiconductor that does not reach an end portion orthogonal to the groove between the first electrodes. A photoelectric conversion semiconductor device having a connecting portion electrically connected in series by the same conductive film as the second electrode filled in the hole or groove formed by the laser scribing method. 2. A reflective metal electrode arranged on a substrate having an insulating surface in which an insulating organic resin film is provided on a flexible metal thin film, and a translucent oxide conductive film on the electrode. A plurality of first electrodes, a non-single-crystal semiconductor that generates photoelectromotive force by light irradiation provided on an opening formed by the laser scribing method between the first electrodes and the electrodes, and the first electrode. A plurality of photoelectric conversion elements having a plurality of second electrodes made of a translucent oxide conductive film provided on the semiconductor corresponding to the electrodes, and first and second electrodes of adjacent elements. Is an opening or a groove formed by a laser scribing method provided inside the non-single-crystal semiconductor, which does not reach the end portion orthogonal to the opening between the first electrodes, and is electrically connected by the oxide conductive film. Light having a connecting portion connected to Conversion semiconductor device.