JPH065776B2 - Method for manufacturing photoelectric conversion device - Google Patents

Description

Description: TECHNICAL FIELD 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 method for manufacturing a photoelectric conversion semiconductor device capable of generating a high voltage by electrically connecting a plurality of photoelectric conversion elements in series.

[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) is a plan view of the photoelectric conversion device 1 viewed from the back side with the transparent glass substrate 2 on the lower side. In the figure, it has an active region 14 that generates a photovoltaic by light irradiation, and an inactive region 15.

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 and 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, the inactive region 1
5, the upper electrode 5 of the cell 13 is connected to the lower electrode of the cell 11 by the contact 18 at the connecting portions 6 and 7, and this is repeated to connect the five cells in series between the external electrodes 8 and 9. ing.

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, the 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 a width of 0.2 to 1 mm, for example, 0.5 mm. Then, if it shifts by 2 mm, the cell width 11 becomes 8 mm and the isolation width 22 is 2.5 mm.
Therefore, 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).

An 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 laser energy in a notch 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,
A method for manufacturing a photoelectric conversion semiconductor device provided with 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]

According to the method for manufacturing a photoelectric conversion device of the present invention, a first conductive film formed linearly on a first conductive film formed on an insulating surface of a substrate having an insulating surface formed by forming an insulating thin film on a flexible metal substrate.
To form a plurality of first grooves by laser scribe method.
Forming a non-single-crystal semiconductor that emits a photoelectromotive force by light irradiation on the first electrode and the first groove between the electrodes. On the other hand, a part of the first electrode is exposed to the inside of the non-single crystal semiconductor that does not reach the end portion orthogonal to the first opening by laser scribing in parallel with the linear first opening. A step of forming an opening or a hole, and a step of forming a second conductive film made of an oxide conductive material in the opening or in the opening and on the non-single-crystal semiconductor, and after forming a connecting portion, A plurality of second trenches are formed in the second conductive film by forming a second trench in parallel with the first trench by a laser scribing method.
And the step of forming and integrating the electrodes.

〔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, the embodiment of the photoelectric conversion device of the present invention used a larger substrate of 20 cm × 60 cm having 100 to 200 active regions 14 on the same substrate at the same time.

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 a linear first open groove 16 in accordance with 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.

The first groove 16 formed by the laser scribing is formed by completely cutting and separating the 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 has been found that the first open groove 16 can be selectively formed in the conductive thin film on the organic resin thin film 2 ″. Moreover, the resistance (width of 1 MΩ or more between the two probes (width: Was 1 cm).

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. It was found that when the frequency was lowered below 10 KHz, the curve 45 became discontinuously 1 MΩ or more and 45 'at 7 kHz or less, and electrical isolation could be performed.

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).

FIG. 4 investigates the necessity of performing the scanning speed at a constant speed in order to obtain the characteristics shown in FIG.

That is, two points 46 are formed by the first open groove 16 of FIG.
47, it is necessary to scan a long distance from the upper side to the lower side at a constant speed.

Furthermore, an example of a constant speed is 30 ~ when the scanning speed is 40 cm / min.
It was possible to form the open groove up to a width of speed within about 50 cm / min (± 25%). That is, board position 49 (width 20 cm)
46 and 47 are shown in FIG. 2 (A). That is, it is important that the scanning speed is within ± 20% of the optimum speed during constant scanning.

Next, 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 applied to the first electrode 3 and the first opening. A uniform film thickness is formed on all upper surfaces of the groove 16.

The semiconductor 4 is, for example S _ix C _1-x in (0 <x <1 generally x = 0.7 to 0.8) of about 150Å to P-type thick, composed mainly of further hydrogen or silicon halogen element is added Let I
-Type semiconductor with a thickness of 0.4-0.8μ, and N-type microcrystallized silicon or N-type Si _x C _1-x (0 <x <1x-0.9)
A PIN junction structure of a semiconductor whose main component is is. this,
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 (microcrystallized Si or Si _x C _1-x 0 <x <1) may be used as a tandem structure of PINPIN structure.

Further, the holes 15 are formed by laser light, and vertical sectional views of BB 'and CC' in FIG. 2B correspond to FIGS. 2B-1 and 2B-2. Shows.

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 opening 15 are the same as the conditions for forming the first opening 16 except that the laser light pulse is discontinuously applied only to the position 15, and the first opening 16 is used as a reference. Was formed by scanning, and the characteristics shown in FIGS. 3 and 4 could be used.

Next, the pattern of FIG. 2 (C) was formed. Vertical sectional views corresponding to DD ', EE', and GG 'in FIG. 2 (C) are shown in FIGS. 2 (C-2), (C-3), and (C-1). ing.

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. For this reason, when using aluminum, tin oxide or ITO, which is an oxide, is required on the upper surface.
Therefore, the IT that constitutes the second electrodes 5, 25, 25 '
When the contact was formed by using O as an oxide, the contact resistance was 3 Ω or less and did not change for long-term use, which was 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. While 50-200μ
The second open groove 20 was formed at a position on the second cell 13 side. Average output of laser light 0.1-0.3W, beam diameter
It was carried out at 10 to 30 μφ, a beam scanning speed of 0.1 to 1 m / min, and generally 0.3 m / min.

In forming the second opening 20, the light irradiation coefficient of the semiconductor is extremely large. A laser beam having a wavelength of 0.6 μ or less, that is, a Q3 switch of 0.53 μ 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.

The second trench 20 is formed by removing the semiconductor 4 therebelow, and can electrically isolate the second electrodes of each element without scooping the first electrode 23. did it.

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

According to the process of the present invention, a photoelectric conversion device of 1 cm × 5 cm is not prepared on an organic resin thin film having an insulating surface on a metal thin film, but 20 cm × 20 cm or 20 cm × 40 cm.
It has become possible to make a large number of photoelectric conversion devices at one time on a substrate of the size.

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 from 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 92% or more. The structure of the present invention was remarkably excellent as compared with 80% of the conventional example.

Furthermore, this conversion efficiency had 6.3% under the fluorescent lamp (300Lx), and the release voltage of 1.9V could be obtained.

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 300 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).

〔The invention's effect〕

(1) In the method for manufacturing the photoelectric conversion device of the present invention, since a substrate having an insulating surface provided with an insulating thin film, for example, an insulating organic resin thin film on a bendable metal thin film is used, it is damaged by mechanical stress. It is difficult to do so, and it is possible to realize a photoelectric conversion device that is resistant to mechanical damage and suitable for cost reduction.

(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 opening, the opening, and the second opening can be formed by a self-registration method by a computer-controlled laser scribing method, the effective area of the cell is large and it is a maskless process. , The manufacturing yield is high.

(4) The width of the laser scribing line of the first and second open grooves for separating cells is extremely small, 10 to 70 μm, the opening is also very small, 10 to 50 μφ, and the first open groove is irradiated with light. Invisible from the surface. As a result, it cannot be confirmed with the naked eye that it has been made into a hybrid, and it is possible to provide a high pay-per-value product.

(5) When the connector is made of metal, leakage is likely to occur due to migrating, but the present invention uses the conductive oxide as 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) In the present invention, the conductive oxide forming the connector is formed of the same oxide as the second electrode of one photoelectric conversion element, so that 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 state when the scanning speed of the present invention is constant.

Claims (1)

[Claims] 1. A laser having a first opening groove linearly formed in a first conductive film formed on an insulating surface of a substrate having an insulating surface formed by forming an insulating thin film on a flexible metal substrate. A step of forming a plurality of first electrodes by a scribing method, and a non-single-crystal semiconductor that emits a photoelectromotive force by light irradiation on the first electrodes and the first groove between the electrodes. Forming step, and the first linear shape for the non-single crystal semiconductor
A groove or an opening that exposes a part of the first electrode is formed in the inside of the non-single crystal semiconductor that does not reach an end orthogonal to the first opening by a laser scribing method in parallel with the groove. And a step of forming a second conductive film made of a conductive oxide in the opening or in the opening and on the non-single crystal semiconductor to form a connecting portion, and then forming the second conductive film on the second conductive film. A step of forming a plurality of second electrodes by forming a second groove in parallel with the first groove by a laser scribing method, and integrating the second electrode. .