JPH06314805A - Photoelectric conversion semiconductor device - Google Patents

Abstract

PURPOSE:To improve the visual product value as a whole device by a method wherein an open groove for isolation to prevent a leak is provided in a region other than the inter-electrode junction section in the circumferential region of either of the first electrode or the second electrode along the end section of the electrode. CONSTITUTION:A first electrode 23' of the cell 13 and a second electrode 25 of the cell 11 establish an ohm contact through the oxide contact and form junction section 12 through a second open groove 18. The contact 17 in the junction section 12 is established by the side surface of the first electrode 23' made by the second open hole 15 or the upper end surface of that side surface and the first electrode 23' to form a side contact structure. The second electrode 25 is closely contacted to this section to establish an electric serial connection. And, the third open groove 20 isolates only the electrode without poly- crystallizing the semiconductor underneath to electrically insulate between the second electrode 25 of element. Thus, it is possible to improve the product value, with the open grooves between the adjacent cells being difficult to be visually recognized.

Description

Detailed Description of the Invention

The present invention relates to compounding a photoelectric conversion element or a cell (hereinafter, simply referred to as a cell) on a flexible light-transmitting organic resin substrate having an insulating surface. The groove is set to 100 μm or less, which is hard to distinguish with the naked eye, and the purpose is to improve the visual commercial value of the entire device.

According to the present invention, an organic resin thin film and a transparent conductive film (CTF) on the upper surface of the organic resin thin film are used for laser scribing (hereinafter referred to as "laser scribe").
We have found experimentally a condition that does not damage the organic resin thin film while scribing the CTF when carrying out (LS). It is not made.

For this reason, in the present invention, the first electrode and the photo-irradiation on the electrode are provided on the substrate of the transparent organic resin thin film (hereinafter referred to as OF) in the cell provided in the active region. Regarding disposing a plurality of elements composed of a non-single-crystal semiconductor that generates electric power and a second electrode on the semiconductor in series, electrical connection between adjacent elements is contacted inside the active region. It is characterized by having been fulfilled by establishing.

It has been required to use a flexible organic thin film as a substrate for inexpensive and mass production of photoelectric conversion devices. The present invention is a translucent OF that enables light irradiation from the OF side.
When the laser light is applied to the CTF consisting of a conductive oxide film containing indium oxide or tin oxide as the main component, the CTF is selectively removed without damaging the OF. As a result of experimental examination of the conditions that can be achieved, it is necessary to optimize the scanning speed without irradiating the laser light on one place for a long time (tens of milliseconds or more). Found that it is possible to remove only CTF. That is, OF has a small thermal conductivity upon irradiation with laser light (generally 1 to 7 × 10 ⁻⁴ Cal / sec / cm ² / cm ² /
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 repetition is done once or several times, the thermal conductivity of this OF is 1/10 of CTF.
^Since it is ³ , on the contrary, it was found that only CTF can be selectively removed only at the place where the laser light is irradiated.

Conventionally, a photovoltaic junction has been used to generate a photoelectromotive force by light irradiation by a PIN junction whose main component is a non-single crystal semiconductor, that is, non-single crystal silicon including amorphous silicon. 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 to electrically isolate the cells 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, a connection part (12) for connecting an active region (14) that generates a photoelectromotive force by light irradiation and each cell (11) (13).
And an inactive region (15). A in FIG. 1 (A)
-As is clear from the fact that the vertical sectional views of A and BB are shown in correspondence with each other in (B) and (C), each cell (11) and (13) is on the glass substrate (2) in the active region. (3) of the transparent conductive film (CTF) of the first electrode of is isolated 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 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 form five cells. A series connection is made between the external electrodes (8), (9).

However, this conventional structure seems to have a high manufacturing yield because there is one semiconductor (4) at first sight. However, in practice, there are three types (first for patterning the first conductive film).
Mask, second mask for forming inactive region, second mask
A third mask for conductive film patterning) is used. However, since the first mask and the third mask are not the self-alignment method in the mask, a mask shift easily occurs. This shift (i.e., 0 for metal masks).
The deviation of 3 to 1 mm is quite natural), and it was found that the effective area of the cell is substantially reduced by 10 to 20%.

Further, since a mask is used, the isolation region (22), which is an open groove between the electrodes in the active region of FIG. 1B, has a width of 0.2 to 1 mm, for example 0.5 mm, so that the cell width is 10 mm. If the cell width (11) is off by 2 mm,
It becomes 8mm and the isolation width (22) becomes 2.5mm, which reduces the effective area by nearly 20%. The area occupied by the outer frame (10) 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.

In the conventional example shown in FIG. 1, the inactive region (15) is provided on the substrate, 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. Furthermore, since the substrate is a glass substrate, it is easily damaged by mechanical stress. Therefore, a transparent and flexible OF is required as a substrate for lowering the price and preventing mechanical damage.

The present invention has been made to achieve such an object. That is, in the present invention, an open groove (width 5 to 70 μm) for separating the plurality of first electrodes from the light irradiation surface side.
Can only be seen. Further, there is no inactive region such as the region (15) in FIG. 1 (A), and the connecting portion constitutes the isolation region of each cell. In addition, since it is a maskless process using LS,
It is possible to adopt a so-called computer-aided self-registration method in which the first open groove is stacked on a television monitor and optically patterned at a predetermined position with reference to the open groove. became.

Further, the contact of the connecting portion between the first electrode of the first cell and the second electrode of the second cell is provided in the semiconductor "inside" (the central portion in FIG. 2) of the substrate, and the contact is conventionally formed. The position of the contact is completely different from that of the example. 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 efficiency of the effective area can be significantly improved. Furthermore, the presence of this open groove is not formed by the structure in which this contact cuts all semiconductors between adjacent cells, but by providing one or more open grooves (20 to 90 μmφ) discontinuously. However, it has other features that it cannot be found with the naked eye from the translucent OF surface side, and the scribe line can be prevented from becoming an obtrusive product.

Further, since the contact is an opening, all the side surfaces around the side 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 Could be reduced to less than 1 Ω.

The present invention has many such features, and the details will be described below with reference to the drawings. 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 Becklite Sumilite (continuous operating temperature 150 to 300 ° C, light transmittance 80 to 92% (thickness 10
0 μm), thermal conductivity 3 to 7 × 10 ^-4 Cal / sec / cm ² /
(° C./cm) was used as the transparent substrate (2), for example, 100 μm thick, 60 cm long (horizontal direction in the drawing), and 20 cm wide). Further, a transparent conductive film such as ITO is entirely formed on the upper surface.
(Approximately 1500Å) + SnO ₂ (200 to 400Å) or a transparent conductive film (1500 to 2000Å) mainly composed of tin oxide added with a halogen element is formed by a vacuum deposition method, a plasma CVD method or a spray method. Let For example, Sumitomo base
Sumilite FS-1300 manufactured by Crite Co. was used. This OF is the upper limit temperature of continuous use 180 ℃, thermal conductivity 4.3 × 10 ^-4 Cal / sec
/ Cm ² / ° C / cm, light transmittance 86.3% (100 μm), surface resistivity 5.4 × 10 ¹⁴ Ω, volume resistivity 1.7 × 10
^{It has 16} Ωcm as a typical example. ITO was formed on this OF to a thickness of 700 Å by sputtering. The sheet resistance was then 200 Ω / cm ² .

This drawing shows the case where four cells are connected in series. That is, the photoelectric conversion device of the present invention uses a larger substrate of 20 cm × 60 cm having 100 to 2000 active regions (14) on the same substrate at the same time. In each cell, the first conductive film was formed on the entire surface of the substrate. Further, this conductive film is formed into a laser having a predetermined shape (here, a wavelength of 1.06 μm or 0.53 μm is used).
A YAG laser) scribe was performed according to a pattern stored and controlled by the micro computer to form the first open groove (16). Further, in order to remove the leak on the outside of the cell, separation grooves (26) and (26 ') were formed. Then, the cell regions (11) and (13) and the external connection electrode parts (8) and (9) were formed.

That is, the YAG laser (emission wavelength 1.06 μ
m, focal length 50 mm, light diameter 50 μm). The conditions were as follows: 6 KHz repeatedly, average output 1.3 W, scan speed (scan speed, hereinafter referred to as SS) 60 cm / min.
Open groove (16) formed by scribing is about 70μ wide
m, length 20 cm (1 cm in the drawing) and depth OF OF each first electrode was completely cut and separated. The width of the first element (11) and the second element (13) was 10 mm. At this time, in the range examined by an electron microscope, no damage or partial deterioration was observed on the OF surface. This laser light
It is presumed that it has a temperature of 1600 ° C or higher, but it did not cause any damage to OF, which has a low heat resistance with a maximum continuous use temperature of about 180 ° C. That is, it was found that the open groove (16) can be selectively formed with respect to the CTF on OF.
In addition, a resistance of 1 MΩ or more (width is
1 cm).

FIG. 3 shows the electric resistance when an open groove is formed by varying the repetition frequency of laser light.
In the drawing, scan speed 60 cm / min, average output 0.
A YAG laser with 8 W and a light diameter of 50 μm was used. Then, when the frequency was lowered below 10 KHz, it became clear that the curve (45) became discontinuously above 1 MΩ (45 ') below 7 KHz and electrical isolation could be performed.
However, at frequencies below 4 kHz, in addition to this CTF, the underlying OF was also damaged at its center (the region with the highest Gaussian energy density). This makes OF
The range shown in (44) was suitable for the LS (laser scribe) of the above CTF.

Further, when a region where only CTF is removed without damaging OF of the underlayer is examined, FIG. 4 is obtained. That is, SS 0 to 120 cm / min, average output 0 to 3 W, repetition frequency 6 KHz, focal length 50 cm, laser light diameter 50 μ
Assuming a YAG laser of m, the region (49), that is, the points A, B, C, D, E,
The area surrounded by F was not damaged by OF and could be removed only by CTF. Furthermore, the region (47) is a region where even CTF cannot be removed, and the region (46) shows that the pulsed light is CT.
It was not continuous on F, and only discontinuous hole grooves were obtained as shown by the broken line. Region (48) was a region that damaged not only the CTF but also the underlying OF. From this, it was found that there is a region (19) in which only CTF can be selectively removed as an open groove without damaging OF underlayer.

A plan view of FIG. 2 (A) and vertical sectional views taken along lines A--A and F--F are shown in (A-1) and (A-2), respectively. 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 open groove (16). A uniform film thickness is formed on the upper surface. This semiconductor (4) is made of, for example, Si _x C _1-x (0 <x <1 generally x = 0.7 to 0.8) P
The mold has a thickness of about 100 Å, and a semiconductor mainly composed of silicon to which I-type hydrogen or a halogen element is added is 0.4-
The thickness was 0.8 μm, and a PIN junction structure of a semiconductor containing N-type microcrystallized silicon or N-type Si _x C _1-x (0 <x <1 x to 0.9) as a main component was used. Of course this is 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 CSi or Si _x C
_It may be a tandem structure of PINPIN structure such as _1-x 0 <x <1).

Further, a second opening (15) is formed by laser light, and vertical sectional views of BB and CC in FIG. 2 (B) are (B-1), (B-2). It corresponds to and is shown. Thus, the second opening (15) exposed the side surface (17) of the first electrode without damaging the surface of OF. At this time, the upper end of the CTF is exposed with a width of 0 to 5 μm, so that the connection is CTF.
The side surface and the upper surface of (3) 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 a pulse of laser light is discontinuously applied only to the position (15). That is, the presence of the semiconductor can be ignored substantially, and the characteristics shown in FIGS. 3 and 4 can be used. Next, the pattern of FIG. 2C was formed. Vertical sectional views corresponding to DD, EE, and GG in FIG. 2C are shown in (C-2), (C-3), and (C-1). That is, the second electrode is formed on the semiconductor (4) by the electron beam evaporation method to a thickness of ITO of 100 to 1600Å, for example, 1050Å, and a metal containing chromium as a main component is formed to a thickness of 500 to 2000Å. Let

Then, in the opening (15), the conductive oxide of ITO was brought into contact with the side surface (17) of the first light-transmissive conductive film (3), and an ohmic contact could be made. .
This chrome has a melting point of 1800 ℃, a boiling point of 2660 ℃, and a thermal conductivity of 0.2cal.
/(Cm.cec.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 ⅕ of 998, and it is estimated that the thermal conductivity in the range of 0.1 to 0.3 is most preferable for laser processing. That is,
It is difficult to make oxides such as aluminum by laser irradiation,
Moreover, it was a particularly excellent metal as a metal that does not easily react with the substrate. Without the ITO underneath, laser light could easily scribe the semiconductor underneath, turning the periphery into a polycrystalline semiconductor. Also, the laser light is transmitted only by ITO,
I virtually scribed only semiconductors. 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
(100-200Å) + Cr (1000-3000Å) was preferred. After this, in FIG. 2 (C), the laser scribe (1
9) was done. This is a YAG laser (wavelength 1.06 μm, 0.53
While monitoring the first open groove with a television monitor, the open groove was formed at a position 50 to 200 μm from that side on the second cell side (13). Average output of laser light 0.5-1.
3 W, beam diameter 30-50 μmφ, beam scanning speed 0.
It was performed at 1 to 1 m / min, generally 0.3 m / min. Thus, the combination of ITO + Cr has a reasonably small thermal conductivity as compared with other metals, so the heat is transferred to the semiconductor, and this semiconductor is used for this second electrode without shifting from the conductive polycrystal. Only the conductor 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.

This semiconductor (3) is a P-type semiconductor layer, I
The n-type semiconductor layer and the n-type semiconductor layer have, for example, one PIN junction, and the n-type semiconductor layer has a microcrystalline or polycrystalline structure. When the electric conductivity thereof is as high as ¹ to 200 (cm) ⁻¹ , the N-type semiconductor layer of the present invention is oxidized (at 10 to 200 hours) at room temperature to 150 ° C. to be an insulator. It was very important to prevent passivation and leak current generation.

Thus, in the connecting portion (12), the first electrode (23 ') of the cell (13) and the second electrode (25) of the cell (11) are brought into ohmic contact by oxide contact. It is through the second open groove (18). In particular, the contact (17) in the connecting portion (12) has a side surface of the first electrode formed by the second opening (15) or a side surface of the first electrode having a width of 0 to 5 μm.
And the upper end face of the electrode, and has a so-called side contact structure. That is, the two cells are only 10-70μ
The side contact of the second aperture of mφ is sufficient, and the material forming the second electrode is brought into close contact with this portion for electrical series connection. As is clear from the cross-sectional views of (C-1) and (C-2), the second electrode (5) is merely formed on the semiconductor (4). And the third groove (20) does not polycrystallize the semiconductor thereunder,
Further, it was possible to electrically isolate the second electrodes of the respective elements by electrically separating only the electrodes without substantially scooping the semiconductor.

Further, in FIG. 2C, an organic resin (28) such as silicone, epoxy or polyimide is coated on the upper surface of these to a thickness of 10 to 100 μm to complete the process. As a result, as is clear from this drawing,
This photoelectric conversion device is, for example, as shown in the drawing, a photoelectric conversion device of 1 cm × 5 cm, which has the same size as the translucent OF.
20cm x 20cm or 20cm x 60cm instead of making one on top
Or, it has become possible to fabricate a large number of photoelectric conversion devices at one time on a large 40 cm × 40 cm identical translucent OF substrate. Finally, these were cut at the boundary of (70) by a cutting method to obtain each photoelectric conversion device. To this end, rather than forming an active region and an inactive region as in the conventionally known photoelectric conversion device, all of them are made substantially active regions, and an open groove by laser light is formed from end to end. , It is important to keep the scanning speed of the laser light constant on a large OF. Otherwise, OF will be damaged in the part where SS is slow.

It is important in consideration of mass production that the open grooves (20), (27) and (27 ') in FIG. 2C are scanned from one end to the other. Of course, these open grooves are not seen from the incident light side at all, so they do not reduce the product value. See also FIG.
As is clear from (C), the effective area of the cell is all other than the extremely small portion of 10 to 300 μm of the connecting portion (12), and the effective area can be 90% or more. The structure of the present invention was remarkably superior to 80% of the conventional example. In view of these, it was found that the present invention has the following great features. That is, according to the present invention, [1] 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 devices are divided into one on each substrate.
It has become possible to adopt a method of making two photoelectric conversion devices. Therefore, it is possible to manufacture at a price of 1/3 to 1/5 that of the conventional one. [2] Since the first opening, the second opening, and the third opening are self-registration system controlled by a computer, the effective area of the cell is large and the cells are produced in the same batch. [3] The manufacturing yield is high because the maskless process by LS has a small variation between photoelectric conversion devices. [4] The width of the scribe line of the first open groove for separating cells is 10 to 100 μm. It is extremely small, and the second opening is also extremely small at 10 to 50 μmφ, and the third opening is completely invisible from the transparent OF 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 FIG. 2, only one second opening (15) was present inside the semiconductor, especially near the center. However, a plurality of holes (2 to 4) are formed in the opening in the Y direction in a broken line.
It may be formed between the first open groove (16) and the third open groove, or may be formed inside the semiconductor (3) along the first open groove (16) in a comb shape.

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. For semiconductors, plasma CVD
Method, low pressure CVD method, optical CVD method or optical plasma CVD method was used. It can be applied not only to PIN junctions, heterojunctions, and tandem junctions mainly composed of non-single-crystal silicon, 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, according to the present invention, a silicon nitride or silicon oxide film is formed on the organic resin in an amount of 300 to 3000 Å.
Needless to say, it may be formed as a barrier layer having the above thickness, 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.

2A and 2B are a plan view and a vertical sectional view of a photoelectric conversion device according to an example, which are shown according to a manufacturing process.

FIG. 3 shows a transparent conductive film on an organic resin in the example.
The change in electric resistance due to the laser scribe when the scribe is performed is shown.

FIG. 4 shows a region where laser scribing is possible when the transparent conductive film on the organic resin of the example is laser scribed.

Claims (1)

[Claims] 1. A first electrode of a conductive film on an organic resin substrate having an insulating surface, a non-single-crystal semiconductor that generates a photoelectromotive force by light irradiation on the first electrode, and the non-single-crystal semiconductor When a plurality of photoelectric conversion elements each having the second electrode are integrated and provided on the organic resin substrate, the first and second electrodes of the photoelectric conversion elements adjacent to each other are formed on both end portions of the non-single crystal semiconductor. A photoelectric conversion semiconductor device having a connecting portion electrically connected in series inside a non-extending portion, wherein inter-electrode connection in an outer peripheral region of at least one of the first electrode and the second electrode A photoelectric conversion semiconductor device, characterized in that an isolation trench for preventing leakage is provided along an end portion of the electrode in a region other than the portion.