JPH069251B2 - Photoelectric conversion semiconductor device manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Use of the Invention] The present invention is directed to the production of a photoelectric conversion semiconductor device in which a photoelectric conversion element or a cell is combined on a flexible organic resin substrate having an insulating surface by a laser scribing method. Regarding the method.

[Conventional technology]

Conventionally, a PIN junction mainly composed of non-single-crystal semiconductors, that is, non-single-crystal silicon including amorphous silicon, has been used to generate photovoltaic power by light irradiation.

However, since the upper and lower electrodes of the semiconductor having such a junction are connected in series, it is necessary to electrically connect the lower electrode of one cell and the upper electrode of the adjacent cell “outside” of the active region. In addition, it is necessary that the cells 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 side with the translucent glass substrate (2) facing down.

In the drawing, it has an active region (14) that generates a photoelectromotive force by light irradiation, and an inactive region (15) having a connecting portion (12) connecting each cell (11) and (13). A- in FIG. 1 (A)
As is clear from the corresponding vertical sectional views of A ′ and BB ′ shown in (B) and (C), each cell (1
The transparent conductive film (3) of the first electrode on the glass substrate (2) in (1) and (13) is separated from each other in each cell.

The semiconductors (4) are connected to each other between the cells. In the inactive region, the upper electrode of the cell (13) is
The lower electrode of the cell (11) is connected with the contact (18) at the connecting portions (6) and (7), and this is repeated to connect five cells in series between the external electrodes (8) and (9). I am letting you.

[Problems of conventional technology]

At first glance, this conventional structure seems to have a high manufacturing yield because there is only one semiconductor (4). However, actually, three types of masks (a first mask for patterning the first conductive film, a second mask for forming the inactive region, and a third mask for patterning the second conductive film) are used. Although the mask is used, since the first mask and the third mask are not the self-alignment method in the mask, a mask shift is likely to occur.

Due to this shift (that is, a shift of 0.3 to 1 mm is quite natural in a metal mask), the effective area of the cell is 10 to 20%.
Was also found to be substantially reduced.

Further, since a mask is used, the isolation region (22), which is a groove between the electrodes in the active region of FIG.
Since it has 2 to 1 mm, for example 0.5 mm, when the cell width is 10 mm, if the cell width is deviated by 2 mm, the cell width (11) will be 8 mm and the isolation width (22) will be 2.5 mm, which is effective for nearly 20%. The area will be reduced. The area occupied by the outer frame 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 made into a self-registration in order to improve its efficiency.

Further, in the conventional example of FIG. 1, the inactive region (15) is provided on the substrate outside the active region, and this inactive region 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 having no inactive region. If the substrate is a glass substrate, it is easily damaged by mechanical stress and is expensive, which is not suitable for mass production.

For this reason, there has been a demand for the use of a flexible translucent organic thin film as a substrate for preventing mechanical damage of photoelectric conversion devices, inexpensive, and for mass production.

[Object of the Invention]

The present invention provides a structure of an integrated photoelectric conversion semiconductor device formed on an organic resin thin film, which has high visual commercial value, high conversion efficiency, and good manufacturing process efficiency. With the goal.

[Means for solving problems]

In order to achieve the above object, the present invention provides a plurality of first electrodes by forming an opening in a translucent conductive film which is a first electrode on a translucent organic resin substrate having an insulating surface. A step of dividing, a step of forming a non-single-crystal semiconductor that generates a photoelectromotive force by light irradiation on the first electrode and the groove between the electrodes, and an interior that does not reach an end of the non-single-crystal semiconductor Exposing the upper surface or the side surface of the first electrode under the non-single crystal semiconductor by irradiating a laser beam on the non-single crystal semiconductor, and thereafter forming a second electrode on the non-single crystal semiconductor. By the step of forming a film and the step of forming an opening in the conductive film to be the second electrode to form the second electrode, the first electrode and the second electrode of different photoelectric conversion elements adjacent to each other are formed. Electrically connecting the electrodes through the apertures to form a series connection. It is characterized.

According to the present invention, when carrying out laser scribing on the organic resin thin film and the transparent conductive film on the upper surface, an experiment was conducted under the condition that the organic conductive thin film was not damaged at all while scribing the transparent conductive film. That they exist,
By utilizing this fact, a photoelectric conversion semiconductor device is manufactured.

That is, in the present invention, on the organic resin substrate, a plurality of first electrodes, a non-single crystal semiconductor that generates a photoelectromotive force by light irradiation on this electrode, and a second electrode on the semiconductor Regarding the arrangement of photoelectric conversion elements connected in series,
It is the maximum in the configuration that electrical connection between adjacent elements can be achieved by providing a contact with laser light through an opening inside the active region that does not reach the end of the non-single crystal semiconductor. Is a feature of.

In the present invention, the contact at the connecting portion between the first electrode of the first cell and the second electrode of the second cell does not reach the end of the semiconductor on the substrate "inside" (see FIG. 2). This is accomplished by providing an opening in the center) with laser light, and the position of the contact is completely different from the conventional one.

The present invention relates to compounding a photoelectric conversion element or a cell (hereinafter simply referred to as a cell) on an organic resin substrate having an insulating surface by adopting the above-mentioned structure, and a plurality of first electrodes of the first electrode are provided from the light irradiation surface side. Only the separation groove can be seen (it is extremely difficult to find with the naked eye because the contact part is a minute hole), and the above-mentioned groove (the cutting line between adjacent cells can be sufficiently distinguished with the naked eye). It is possible to improve the visual commercial value of the entire device by making it difficult to set 100 μ or less, preferably 5 to 70 μ.

That is, when forming this contact, by forming one or a plurality of open grooves (20 to 90 μφ) discontinuously, instead of forming an open groove in a structure that cuts all semiconductors between adjacent cells, The presence of the groove cannot be found substantially with the naked eye from the transparent organic resin thin film surface side, and the connecting portion can be prevented from being an eyesore, and the visual commercial value can be improved.

Moreover, since the contact is an opening, all side surfaces around the side circle of the hole can form a contact at the connecting portion between the first electrode and the second electrode, and the contact resistance at this portion is 1Ω. I was able to lower it below.

Further, this internal contact can reduce the series resistance applied to the photoelectric conversion device of the transparent conductive film. As a result,
Since the connecting portion is not provided outside the cell, the effective area and the conversion efficiency can be remarkably improved.

In addition, the photoelectric conversion semiconductor device formed by this manufacturing method does not have any inactive region such as the region (15) in FIG. 1A, and the connecting portion constitutes the isolation region of each cell. be able to.

Further, a first electrode on the transparent substrate in the cell provided in the active region, a non-single-crystal semiconductor that generates a photoelectromotive force on the electrode by light irradiation, and a second electrode on the semiconductor. And each of them can be manufactured as a structure having substantially the same shape and substantially the same position (self-registration), and the manufacturing yield can be improved and the efficiency of the manufacturing process can be improved due to the deviation of the alignment accuracy of the composite. .

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

〔Example〕

The present inventors have proposed a transparent organic resin thin film that enables light irradiation from the substrate side, and a transparent conductive film made of a conductive oxide film containing indium oxide or tin oxide as a main component on the transparent organic resin thin film. Then, when the laser light was irradiated, the conditions under which the transparent conductive film could be selectively removed without damaging the transparent organic resin thin film were experimentally examined.
Without irradiating one place for a long time (tens of milliseconds or more),
It was also found that it is possible to remove only the transparent conductive film by optimizing the scanning speed.

That is, the light transmissive organic resin thin film has a small thermal conductivity due to the irradiation of laser light (generally 1 to 7 × 10 ⁻⁴ Cal / sec / cm ² / cm ² ).
(° C./cm)), therefore, when a laser pulse is repeatedly applied to the same position, heat is accumulated in the organic resin, and the heat causes the resin to be carbonized and cut. However, if the number of repetitions is once or several times, since the thermal conductivity of this transparent organic resin thin film is about 1/10 ^{3 of} that of the transparent conductive film, conversely, only the transparent conductive film is selected. It was found that it was possible to remove only the portion irradiated with laser light, and based on this fact, the photoelectric conversion semiconductor device of the present invention was produced by laser scribing.

Since the present embodiment is a maskless process using laser scribing, a so-called computer-aided type in which the first open groove is observed on a television monitor and optically patterned at a predetermined position with reference to the open groove.・ It is now possible to use the self-registration method.

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

In the drawing, a translucent organic resin thin film substrate having an insulating surface, such as Sumitomo Bakelite Sumilite (continuous operating temperature 150 to 300 ° C., light transmittance 80 to 92% (thickness 100 μ),
The thermal conductivity of 3 to 7 × 10 ^-4 Cal / sec / cm ² / (℃ / cm) is used as the transparent substrate (2) (for example, thickness 100μ, length (horizontal direction in drawing) 60 cm, width 20 cm). Using.

In this example, Sumilite FS-1300 manufactured by Sumitomo Bakelite Co., Ltd. was used as a representative example. This translucent organic resin thin film has a maximum continuous use temperature of 180 ° C and a thermal conductivity of 4.3 × 10 ^-4 Cal / sec /
cm ² / (℃ / cm), light transmittance 86.3% (100μ thickness), surface resistivity 5.4 × 10 ¹⁴ Ω, volume resistivity 1.7 × 10 ¹⁶ Ω
have cm.

Further, a transparent conductive film such as IT
O (approximately 1500Å) + SnO ₂ (200 to 400Å) or a transparent conductive film (1500 to 2000Å) mainly composed of tin oxide to which a halogen element is added is formed by a vacuum deposition method, a plasma CVD method or a spray method. It was

700 Å ITO is sputtered on this translucent organic resin thin film.
Was formed to a thickness of. Then the sheet resistance is 200Ω /
Had a □.

This drawing shows the case where four cells are connected in series.
That is, in the photoelectric conversion device of the present invention, a larger 20 cm × 60 cm base having 100 to 2000 active regions 14 on the same substrate at the same time was used.

In each cell, the first conductive film was formed on the entire surface of the substrate. Further, a laser (here, a YAG laser having a wavelength of 1.06 μ or 0.53 μ) was scribed on the conductive film according to a pattern stored and controlled by a microcomputer to form a first open groove (16).

In addition, on the outside of the cell, in order to remove the residuals during fabrication and leakage due to pressure from the outside, etc.
6) and (26 ') were formed. Then, the cell regions (11) and (13) and the external connection electrode portions (8) and (9) were formed.

That is, YAG laser (emission wavelength 1.06μ, focal length 50m
m, light diameter 50 μ). The conditions were 6 kHz at the same time repeatedly, an average output of 1.3 W, and a scan speed (scan speed) of 60 cm / min.

The open groove (16) formed by scribing is about 70μ wide,
The length was 20 cm (1 cm in the drawing) and the depth was such that each first electrode of the translucent organic resin thin film was completely cut and separated.

The width of the first element (11) and the second element (13) is 10
mm.

At this time, no damage or partial deterioration was observed on the surface of the translucent organic resin thin film in the range examined by an electron microscope. It is presumed that this laser beam has a temperature of 1600 ° C. or higher, but it did not damage the translucent organic resin thin film, which has only low heat resistance such that the continuous use upper limit temperature is about 180 ° C.

That is, it was found that the open groove (16) can be selectively formed in the transparent conductive film on the transparent organic resin thin film. Moreover, a resistance of 1 MΩ or more (width of 1 cm) could be obtained between the two probes.

FIG. 3 shows the electric resistance when the repetitive frequency of the laser beam is made variable and an open groove is formed.

In the drawing, scan speed 60 cm / min, average output 0.
A YAG laser with 8 W and a light diameter of 50 μ was used. Then, when the frequency was lowered below 10 KHz, it became clear that the curve (45) became discontinuously above 1 MΩ (45 ') at 7 KHz or less, and electrical isolation could be performed.

However, at frequencies below 4 KHz, in addition to the translucent conductive film, the underlying translucent organic resin thin film was also damaged at its center (the region with the highest Gaussian energy density).

From this, the range shown in (44) was suitable for the laser scribing of the translucent conductive film on the translucent organic resin thin film.

Further, when a region in which only the transparent conductive film was removed without damaging the transparent organic resin thin film as the underlying layer was examined, FIG. 4 was obtained.

That is, scan speed is 0 to 120 cm / min, average output is 0
Assuming that the YAG laser is ˜3 W, repetition frequency 6 KHz, focal length 50 cm, and laser light diameter 50 μ, the area (49), that is, points A, B,
In the area surrounded by C, D, E, and F, the transparent organic resin thin film was not damaged and could be removed only by the transparent conductive film.

Further, the region (47) is a region where even the transparent conductive film cannot be removed, and the region (46) is such that the pulsed light is not continuous on the transparent conductive film and has a discontinuous hole groove as shown by a broken line. I only got it. The region (48) is a region that has damaged not only the transparent conductive film but also the underlying transparent resin thin film.

This revealed that there is a region (19) in which only the transparent conductive film can be selectively removed as an opening without damaging the underlying transparent organic resin thin film.

2A is a plan view and FIG. 2A is a vertical sectional view taken along lines AA ′ and FF ′.

Next, as shown in the plan view of FIG. 2 (B), a non-single crystal semiconductor added with hydrogen or fluorine, which generates a photoelectromotive force by light irradiation, is formed on the electrode (3) and the groove (16). A uniform film thickness on the upper surface of. For semiconductors, plasma CVD
Method, low pressure CVD method, optical CVD method or optical plasma CVD method.

This semiconductor (4 ') is, for example, SixC1 _-x (0 <x <1 generally x = 0.7 to 0.8) made of P-type silicon having a thickness of about 100 Å and further added with I-type hydrogen or a halogen element. With a thickness of 0.4-0.8μ, and N-type microcrystallized silicon or N-type SixC _1-x (0 <x <1 x-0.9)
A PIN junction structure of a semiconductor whose main component is is.

Of course, this is P (SixC _1-x x = 0.7-0.8) -I (Si)
-N (μCSi) -P (SixC _1-x x = 0.7 to 0.8) -I (SixC
e _1-x x = 0.6 to 0.8) -N (microcrystallized CSi or SixC _1-x 0
A tandem structure of PINPIN structure such as <x <1) may be used.

Further, the second opening (15) is formed by laser light,
A vertical cross-sectional view of BB ′ and CC ′ in FIG.
-1) and (B-2) are shown.

Thus, the second opening (15) exposed the side surface (17) of the first electrode without damaging the surface of the translucent organic resin thin film.

At this time, since the non-single-crystal semiconductor is more easily removed than the transparent conductive film, exposing the upper end portion of the transparent conductive film with a width of 0 to 5 μ results in the connection being the transparent conductive film (3). The side surface and the upper surface of each of the contacts form a contact of the connecting portion.

The conditions for forming the second opening (15) are the same as the conditions for forming the first opening except that the laser beam is applied to the position (15) discontinuously.

In other words, it is safe to ignore the existence of semiconductors,
The characteristics shown in FIGS. 3 and 4 could be used.

Of course, this laser light may be further weakened to about 1/2 to scribe only the semiconductor without scribing the transparent conductive film, and the contact may be achieved on the upper part (upper surface) of the transparent conductive film. .

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 (C-2), (C-3), and (C-1).

That is, first, a second electrode was provided on the semiconductor (4) by electron beam evaporation to a thickness of ITO of 100 to 1600Å, for example 1050Å.

Then, in the opening (15), the conductive oxide of ITO comes into contact with the side surface (17) of the first transparent conductive film (3),
I was able to make ohmic contact.

Further, a metal containing chromium as a main component was formed to a thickness of 500 to 2000Å.

This chrome has a melting point of 1800 ℃, a boiling point of 2660 ℃, and a thermal conductivity of 0.2cal.
/(Cm.sec.deg). In particular, this thermal conductivity is 4 times higher than that of other metals such as titanium, which is 0.05, and that of silver is 0.
It is 1/5 of 998. It is said that the thermal conductivity in the range of 0.1 to 0.3 is most preferable for laser processing.

In laser irradiation, this chromium film was particularly excellent as a metal that was less likely to form an oxide and was less likely to react with the base than aluminum or the like.

Also, if there is no ITO below this, the laser light easily scribes the semiconductor underneath and turns the periphery into a polycrystalline semiconductor. Moreover, the laser beam was transmitted only by ITO and substantially scribed only the semiconductor. From these, the back electrode was optimally a two-layer film of ITO and chromium.

In order to improve the characteristics by utilizing the reflectivity of the back surface electrode, the above-mentioned ITO (1050Å) + Ti (20Å) or Ag (100-200
Å) + Cr (1000-3000 Å) was preferred.

After that, laser scribing (19) was performed in FIG. 2 (C) to form a third groove. In this step, the YAG laser (wavelength 1.06μ, 0.53μ) is monitored on the TV monitor for the first open groove, and 50 to 200μ from that side on the second cell side.
An open groove was made at the position entered in (13). The average output of the laser beam was 0.5 to 1.3 W, the beam diameter was 30 to 50 μφ, and the beam scanning speed was 0.1 to 1 m / min, generally 0.3 m / min.

By doing so, the thermal conductivity due to the combination of ITO + Cr is appropriately smaller than that of other metals, so without changing the composition of the semiconductor caused by excessively transmitting the heat to the semiconductor, this first Only the conductor for the second electrode could be scribed and removed.

Further, it is preferable to dissolve away the third open groove (20) with a cleaning solution such as acetone in order to remove the residue.

The semiconductor (3) is a P-type semiconductor layer, an I-type semiconductor layer,
It may have, for example, one PIN junction with the N-type semiconductor layer, and this N-type semiconductor layer may have a microcrystalline or polycrystalline structure. When the electric conductivity thereof is as high as ¹ to 200 (Ωcm) ⁻¹ , the N-type semiconductor layer is oxidized (10 to 200 hours) at a temperature of room temperature to 150 ° C. in the present invention to be an insulator. Preventing passivation and leakage current generation was extremely important.

Thus, at the connection (12), the first electrode of the cell (13)
Oxide contact between (23 ') and the second electrode (25) of the cell (11) is made by oxide contact through the second opening (18). In particular, the contact (17) in the connecting portion (12) is formed by the side surface or side surface of the first electrode formed by the second opening (15) and the upper end surface of the first electrode having a width of 0 to 5 μ. And has a so-called side contact structure. That is, it is sufficient for the two cells to have the side contact of the second opening of only 10 to 70 μφ, and the material forming the second electrode is brought into close contact with this portion for electrical series connection.

In FIG. 2, only one second hole (15) was present inside the semiconductor, especially near the center. However, even if a plurality of holes (2 to 4) are formed between the first and third grooves in the Y direction in a broken line in the Y direction, the first holes are formed inside the semiconductor (3) in a comb shape. It may be formed along the open groove (16).

As is clear from the sectional views of (C-1) and (C-2),
A second electrode (5) is formed on the semiconductor (4).
Then, the third open groove (20) separates only the electrodes without polycrystallizing the semiconductor therebelow and substantially without scooping the semiconductor to electrically connect the second electrodes of the respective elements. I was able to isolate it.

Further, in FIG. 2 (C), an organic resin
(28) For example, silicone, epoxy or polyimide 10
Completed by coating to a thickness of ~ 100μ.

As a result, as is clear from this drawing, this photoelectric conversion device is, for example, as shown in the drawing, one photoelectric conversion device of 1 cm × 5 cm is formed on a translucent translucent organic resin thin film of the same size. Instead, it has become possible to make a large number of photoelectric conversion devices at once on a large translucent organic resin thin film substrate of 20 cm × 20 cm or 20 cm × 60 cm or 40 cm × 40 cm.

Finally, these were cut at the boundary of (70) by a cutting method to obtain each photoelectric conversion device. To this end, instead of forming an active region and an inactive region as in the conventionally known photoelectric conversion device, all are made substantially active regions, and laser light is used to form open grooves from end to end, It is important to keep the scanning speed of light constant on a large transparent organic resin thin film. Otherwise, a loss layer will be formed on the translucent organic resin thin film in the portion where the scan speed is slow.

It is important for mass production that the open grooves (20), (27), (27 ') in FIG. 2 (C) are scanned from end to end.
Of course, these open grooves are not seen from the incident light side at all, so they do not reduce the product value.

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 their design specifications.

〔The invention's effect〕

The present invention achieves the connecting portion of each cell by an internal contact through an opening, and the first opening groove width for separating each cell is extremely small as 10 to 100 μ by using a laser and the like. Of 10 to 50 μφ, which is extremely small, and the third groove is completely invisible from the transparent organic resin thin film surface side. As a result, it could not be confirmed with the naked eye that it was hybridized, and it was possible to give a high added commercial value.

In addition, the effective area of the cell is all other than the extremely small part of the connecting part (12) of 10 to 300μ width, and the effective area can be 90% or more, which is 80% of the conventional example. In comparison, the method of the present invention was remarkably excellent.

In addition, since the formation of the first opening, the second opening, and the third opening can be performed by the self-registration, the manufacturing process can be extremely simplified, and each photoelectric conversion device manufactured in the same batch. The manufacturing yield was high because there was little variation. Moreover, the effective area could be increased.

According to the present invention, a large number of photoelectric conversion devices are simultaneously formed on a large-area substrate of a translucent organic resin film, and the photoelectric conversion device is divided on each substrate to form one photoelectric conversion device. It has become possible. Therefore, 1/3 to 1/5 of the conventional
It is now possible to manufacture at the price of (30-50 yen per unit).

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

The present invention shows the case where the transparent conductive film is brought into close contact with the transparent organic resin. However, it goes without saying that in the present invention, a silicon nitride or silicon oxide film may be formed as a barrier layer with a thickness of 300 to 3000 Å on an organic resin, and a translucent conductive film may be formed thereon. .

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a conventional photoelectric conversion device. FIG. 2 shows a plan view and a vertical sectional view of a photoelectric conversion device according to the present invention in accordance with the manufacturing process. FIG. 3 shows a change in electric resistance due to laser scribing when the transparent conductive film on the organic resin of the present invention is laser scribed. FIG. 4 shows a region where laser scribing is possible when the transparent conductive film on the organic resin in this example is laser scribed.

Claims (3)

[Claims] 1. A step of dividing into a plurality of first electrodes by forming an opening in a light-transmitting conductive film which becomes a first electrode on a light-transmitting organic resin substrate having an insulating surface, and the first electrode. A step of forming a non-single-crystal semiconductor that generates a photoelectromotive force by light irradiation on the first electrode and the groove between the electrodes; and irradiating the inside of the non-single-crystal semiconductor with a laser beam Forming a hole to expose the upper surface or side surface of the first electrode below the non-single-crystal semiconductor, and thereafter forming a conductive film to be a second electrode on the non-single-crystal semiconductor; By forming an opening in the conductive film to be the second electrode to form the second electrode, the opening is formed between the first electrode and the second electrode of different photoelectric conversion elements adjacent to each other. Photoelectric conversion semiconductor characterized in that they are electrically connected to each other to form a series connection.置作 made way. 2. The first electrode according to claim 1, wherein an opening is formed inside the non-single crystal semiconductor so as not to reach an end of the non-single crystal semiconductor to expose an upper surface or a side surface of the first electrode. A method for manufacturing a photoelectric conversion semiconductor device, wherein a contact is formed by closely providing a conductive oxide material forming the second electrode on the side surface or the side surface and the upper surface. 3. The electrode according to claim 1, wherein an end of the electrode is provided in a region other than the inter-electrode connecting portion in the outer peripheral region of at least one of the first electrode and the second electrode. A method for manufacturing a photoelectric conversion semiconductor device, characterized in that an isolation trench for preventing leakage is provided along the portion.