JPH0566755B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a photoelectric conversion device in which a plurality of photoelectric conversion elements (also simply referred to as elements) using non-single crystal semiconductors including amorphous semiconductors are electrically connected in series. The present invention relates to the structure of an electrode at a panel side end of a connection portion between elements in .

[Conventional technology]

In general, panels such as glass substrates on which photoelectric conversion devices are formed have a substrate thickness of 1 μm or more at the side edges.
It has a concave or convex warp of 0.1mm. Since the laser beam is out of focus at such side ends, the first conductive film cannot be completely electrically separated into the shape of the first electrode required for a predetermined element.

Furthermore, when attempting to form a film by electron beam evaporation using a CTF (transparent conductive film) whose main components are tin oxide or indium oxide as the first electrode, the CTF wraps around the side of the substrate. It had been covered with a film.

For this reason, even if it is attempted to form the first electrode for each element by electrically separating the first conductive film only by an opening groove formed by LS (hereinafter referred to as the first opening groove), the electrical There was a problem in that the device regions could not be separated because of the large-scale shot.

[Problem to be solved by the invention]

In order to process an integrated photoelectric conversion device only by a laser scribing (LS) process, the present invention provides a photoelectric conversion device having a structure that prevents shorting between electrodes of a photoelectric conversion element near the edge of a substrate. The purpose is to obtain equipment.

[Means to solve the problem]

The present invention provides a photovoltaic device having a first electrode provided on an insulating substrate, a non-single crystal semiconductor having at least a PIN junction provided on the electrode, and a second electrode provided on the semiconductor. A photoelectric conversion device in which a plurality of conversion elements are electrically connected to each other in series and arranged on the insulating substrate, wherein at an end perpendicular to an end used for connection of the photoelectric conversion elements, An opening groove is formed in the first electrode along an end portion, the non-single crystal semiconductor is provided to cover the opening groove, and an end portion of the second electrode is formed above the opening groove or in the opening groove. It is characterized by being located closer to the element region than above the groove.

According to the present invention, an open groove that is perpendicular to the open groove that separates the photoelectric conversion element is formed at the end of the photoelectric conversion element, and by covering the open groove with a non-edge crystal semiconductor, the upper and lower electrodes of the photoelectric conversion element are connected to each other. This prevents the vehicle from being shot on the side of the vehicle.

In addition, if a second electrode is formed that protrudes outward to a greater extent than the non-single crystal semiconductor, the second electrode that extends outward at the connection portion between each element will overlap the first electrode outside the groove. electrically connected to
Although the first electrodes of adjacent elements may be shot, the end of the second electrode may be shot from above the groove of the first electrode or from above the groove as in the present invention. This can be prevented by locating it on the element region side (inside side).

The present invention has the above-mentioned effects and further prevents deterioration of the conversion efficiency of a photoelectric conversion device.

〔Example〕

In this example, when a photoelectric conversion device is manufactured by laser scribing (hereinafter referred to as LS),
At the connection part where each element is connected in series, the first conductive film on the substrate and the second conductive film on the semiconductor may shoot each other due to their sizes, preventing electrical series connection. In order to prevent aging, the second conductive film on the semiconductor is made to be the same or smaller than the first conductive film on the substrate.

In general, the periphery of a photoelectric conversion device panel (hereinafter simply referred to as a panel), especially when this panel is rectangular or rectangular, the connecting part, that is, the lower side of one element, even in the two sides where external extraction electrodes are not formed. electrode (the first electrode made of the first conductive film)
(electrode) and the upper electrode (second electrode made of the second conductive film) of the adjacent element are connected by a conductor.

In this example, in order to eliminate such defects, an open groove (hereinafter referred to as the fourth open groove) is formed using a laser beam inside the edge of the substrate (generally 0.3 to 5 mm), and a groove for each element is formed. One electrode is surrounded by four grooves.

Thus, it is useful in that it is possible to eliminate electrical shorts between electrodes due to variations in laser processing due to substrate warping at the base end of the substrate as described above.

However, it has been found that when the second conductive film is formed on a semiconductor using only the fourth groove, the connecting portion connecting each element in series may be shot. In other words, if a second conductive film is formed that protrudes outward from the first conductive film, the second electrode at this connecting portion is connected to the first conductive film outside the groove of the adjacent element. This electrically connects the conductive film with the first conductive film under the second electrode due to leakage, resulting in shorting at the periphery between the upper and lower electrodes of the element. That's what happens.

In this example, by providing the second conductive film above the fourth groove or smaller inside the fourth groove, it is possible to shoot adjacent elements in series at the side edges for the first time in one panel. It connects the objects without causing any problems.

The present invention achieves such an integrated structure without using a mask, but during this integration, the side edges of the substrate, which tend to require extra steps, are achieved in the same LS process as the integration process. be.

Generally, in the LS method, 10 to 100 μm, for example,
It is possible to separate the two regions by a linear groove with a width of 50 μm. However, in this LS method, it is extremely difficult to selectively remove surfaces, which increases the manufacturing cost. moreover
In the LS method, it is preferable to have straight lines or points because it increases productivity, but if a curved line is scanned in a complicated manner, the scanning speed becomes slow and the price increases. This results in LS
In manufacturing the panel periphery and integrated structure in this method, the achievement of straight and linear grooves increases industrial productivity and is extremely important. In this embodiment, these features are fully utilized,
The peripheral part, that is, the pad part and the side end part of the photoelectric conversion device are formed.

Furthermore, in this embodiment, in addition to using this laser scribing process, it is important to provide a degree of redundancy (margin) in the alignment accuracy of the scribe lines. Therefore, the first electrode (lower side) between adjacent elements and the second electrode (upper electrode) of the other element are electrically connected to the first electrode and its side surface by the lead extending from the second electrode. By connecting the scribe line to the groove, it was possible to provide redundancy in the position of the scribe line opening groove.

FIG. 1 shows a top view of a panel 50 of a photoelectric conversion device using the present invention, which is the present embodiment. That is, in the drawing, the photoelectric conversion elements 31, 1
1 are connected in series through a connecting portion 12 and integrated to provide a photoelectric conversion device 50. External extraction electrodes 5 and 45 are provided at both ends.

Separation grooves 62 are provided at the upper and lower ends of the panel to prevent electrical contact with the frame.

In the panel shown in Figure 1, its size is 20cm x
Any size such as 60 cm, 40 x 120 cm, 40 cm x 60 cm, etc. can be obtained by design.

A longitudinal cross-sectional view taken along line A-A' in FIG. 1 is shown in FIG. Furthermore, the longitudinal cross-sectional view of B-B′) is shown in the third
FIG. 3B shows C enlarged from FIG. 3A. The numbers correspond to each other.

FIG. 2 shows a longitudinal sectional view of FIG. 1 along line A-A'. That is, it is a longitudinal sectional view showing the manufacturing process of the present invention.

In FIG. 2A, a substrate having an insulating surface, such as a transparent substrate 1 or a glass plate (for example, 1.2 mm thick,
The length (in the left and right direction in the drawing) is 60 cm and the width is 20 cm) or translucent organic resin was used. Furthermore, a transparent conductive film such as ITO (approximately 1500 Å) +
A light-transmitting conductive film (1500 Å) whose main component is SnO ₂ (200 to 400 Å) or tin oxide doped with a halogen element.
~2000Å) by vacuum evaporation, LPCVD, plasma
It was formed by CVD method or spray method.

Although this first conductive film is not necessary in the external lead electrode section, an increase in manufacturing cost due to the use of a mask was avoided. In this way, a CTF is also formed on the electrode region 5. After this, from the top of this board, YAG
Apply 0.5 to 3W output using a laser processing machine (manufactured by Nippon Laser) to create a spot with a diameter of 30 to 70μm, e.g. 50μm.
φ, a frequency of 7 KHz, and a pulse width of 10 μm seconds are controlled by a microcomputer to form open grooves 13 and 13' for scribe lines by scanning.
The area between each element area and the external extraction electrode area 5 were divided. Then, first electrodes 37 and 39 were produced.

Open groove 13,1 formed by this first LS
3' had a width of about 50 μm and a length of 20 cm, and the depth was such that each of the first electrodes was completely cut and separated. Also at this time,
An open groove was formed by passing through from the upper end to the lower end of the drawing in FIG. The scanning speed for forming the open grooves was set at a high speed of 2 m/min.

In this way, the external extraction electrode region 5, the first element region 31, and the second element region 11 were formed.
The width of these elements was 10 to 20 mm.

In addition, as shown in FIG. 3, a fourth opening 56 for a separation groove on the side of the substrate was also fabricated by the same LS process. As a result, the laser beam is out of focus due to the non-uniform conductive film 33 in the peripheral part of the element region 31 in the panel, that is, the warpage of the substrate in the concave and convex parts at the side edges, and the area 3 where the open grooves 13 and 13' cannot be formed.
4 and electrically separated. Thus, in the active region 32 where the device is formed, the device 31,
Eleven first electrodes were electrically isolated.

After that, this conductive film, the first open groove and the fourth open groove are covered and the upper surface is coated with plasma CVD or LP.
CVD method, optical CVD method, optical plasma CVD method, LT
In the case of a non-single-crystal semiconductor that generates photovoltaic force by light irradiation using the CVD method (referred to as HOMO CVD method), the non-single-crystal semiconductor layer 3 having a PN or PIN junction is formed in a thickness of 0.2 to 1.0 μm, typically 0.4 to 0.6 μm. It was formed to a thickness. A typical example is a P-type semiconductor ( _SI
C _1-X
Alternatively, a non-single crystal semiconductor 3 having one PIN junction made of a semiconductor 44 of Si _X C _1-X (0<X<1, for example, X=0.9) was used. Furthermore, as this semiconductor, two PIN junctions are made of a P-type semiconductor (Si _X C _1-X ) - I-type Si semiconductor - N-type Si semiconductor - P-type Si semiconductor - I-type Si _X Ge _1-X semiconductor - N-type semiconductor. Tandem-type PINPIN having one PN junction and one PN junction...PIN junction semiconductor 3
You can also use it as

The non-single crystal semiconductor 3 was formed to have a uniform thickness over the entire surface of the CTF 2 and the grooves 13 and 13'. Furthermore, as shown in FIG. 2B, a second open groove 18 is formed on the left side of the first open groove 13 with a width of 50 μm and a distance 17 of 100 to 200 μm.
It was formed by the LS process.

The second open groove 18 thus exposed the side surfaces 8, 9 of the first electrode. In this open groove, CTF
may expose not only the side surfaces but also the upper surface or the upper surface and the side surfaces as a part constituting the contact.

The presence of the right side surface 9 of the first electrode formed by the second open groove causes the side surface 1 of the first electrode 37 to
It is provided over the first electrode position of the first element on the left side of 6.

As shown in FIG. 2B, by entering the inside of the first electrode 31, the side surfaces 8 and 9 of the first electrode are exposed.

In this way, a part of the first electrode 37 of the first element remained on the right side of the second groove.

If there is no such remaining region, the vicinity of this open groove will be laser annealed by the photothermal heat (up to 2000° C.) of the laser beam, and the region will become polycrystalline and the insulation will deteriorate. Since this polycrystal is extremely likely to occur on the surface of the glass substrate, the convex portion 9 prevents this crystallization and prevents the side surfaces 9 and 16 from becoming electrically short. That is, Fig. 2C
The first electrode 3 of the same element as the first electrode 39 in
I was able to prevent 8 from shooting.

The CTF remaining in this portion 9 had a width of 20 to 200 μm. This laser beam is a little too strong at 0.5 to 3 W and removes all of the CTF 37 in the depth direction.As a result, even if the second electrode 38 is placed close to the side surface 8 as shown in FIG. 2C, there is no practical effect. No problem. That is, it is extremely important for the industrial application of the present invention to be able to provide a margin for the intensity of the output pulse of the laser beam.

In FIG. 2, as shown in FIG. 2C, a second conductive film 4 on the back side is further formed on this upper surface, and a third groove 20 for cutting and separation is provided by a third LS method. Ta.

This second conductive film 4 is made of a transparent conductive film of 100~
It is made of ITO (indium tin oxide) to a thickness of 1400 Å, and titanium (10 to 50
Å), silver (100-500 Å) and chromium were formed to a thickness of 300-3000 Å. or 300 ~ chrome on ITO
It was formed to a thickness of 3000 Å. For example, if ITO is 1050Å,
Chromium has a two-layer structure of 1500 Å.

Nickel or other metals may be formed on the chromium, or nichrome may be used instead of chromium.

The size of the second conductive film is such that, as shown in FIG. 57 are provided.

The end portion of the second conductive film was manufactured by masking the peripheral portion with a substrate holder (frame) when the second conductive film was manufactured by electron beam evaporation.

As described above, since the end of the second conductive film is provided above and inside the fourth groove of the first conductive film (preferably inside the inner end 35 of the groove), It was possible to prevent the two electrodes from being short-circuited via the connecting portion 12 by shorting the first electrode of the same element and the first conductive film of the side end portion 34.

A case is shown in which the back electrode is irradiated with a laser beam from above and the second electrode is cut and separated to form a third groove 20 (width 50 μm).
Irradiation with this laser light made it possible to selectively remove the sublimable conductors ITO and chromium. At this time, since the laser beam is focused on this second conductive film, the side part 3 of the panel
4 (FIG. 3), it was found that it was substantially difficult to form an open groove 68 in the semiconductor underneath.

Furthermore, the upper part of the semiconductor under this third trench was oxidized with 40 to prevent crosstalk (leakage current) between the respective electrodes.

Thus, as shown in FIG.

FIG. 2D shows an attempt to further complete the present invention as a photoelectric conversion device, that is, a silicon nitride film 2 is made by plasma vapor phase method as a passivation film.
1 to a thickness of 500 to 5000 Å to prevent leakage current between each element. Further, an external lead terminal 23 is provided at the peripheral portion 5. These were filled with an organic resin 22 such as polyimide, polyamide, Kapton or epoxy.

Thus, for irradiation light 10, each element has a width of 14.35 cm on a substrate (60 cm x 20 cm) as in this example.
mm, Width of connecting part 150μm, Width of external lead electrode part
Effective area (192mm x
14.35 mm x 40 stages 1102 cm ² or 91.8%). As a result, if the segment has a conversion efficiency of 9.3%, the panel has a conversion efficiency of 7.6% (AM1 (100
It was possible to have an output power of 9.3W at mW/cm ² )).

Furthermore, since no metal mask is used, there is no industrial problem in the manufacturing process of large-area panels, making it extremely suitable for large-area, low-cost mass production for generating large amounts of power.

As a result, the effective area of the panel could be improved.

FIG. 3 is an enlarged view of BB' and C in FIG.

In FIG. 3A, it has two elements 31, 11 and a connecting part 12. Also at the side end portion 34, the CTF 59 remains as shown in FIG. 3B. Therefore, even if these conductors remain, in order to prevent the elements 31 and 11 from becoming inoperable, even if this conductor 59 remains,
This part has a structure that allows the panel to be fixed to the outer frame 60. That is, the first conductive film 2 has the fourth groove 5 along the side edge 33 of the substrate.
6 is formed. Further, a semiconductor 3 is formed to cover this fourth trench. Thereafter, a second conductive film is formed on this semiconductor so that its end 57 forms a fourth trench 56.
It is located above or inside the .

Even if the first electrodes of adjacent elements were shot due to the separation groove 62, the fourth open groove 56 could prevent the shooting. Also carbon fiber frame 6
0, the conductor 34 is pressurized, and even if shot, the characteristics of the elements 31 and 11 do not deteriorate in any way.

That is, the side end portions can be stably fixed to the outer frame 60 etc. for the first time through the open grooves 56 and the separation grooves 62 formed by the side ends 57. Furthermore, even if the frame and the photoelectric conversion device are fixed with resin 63, it has become possible to obtain a device with sufficiently high reliability.

Furthermore, this panel for example 40cm x 20cm or
By combining 6 or 4 pieces of 60cm x 20cm in series within an aluminum sash frame, it is packaged.
It is possible to install a 120cm x 40cm NEDO standard high power panel.

In addition, this NEDO standard panel is made into a composite body by gluing another glass plate or other mechanical substrate to the reflective surface side (upper side in the drawing) of the photoelectric conversion device of the present invention using a laminating adhesive such as Seaflex, and It is also effective to increase mechanical strength against rain, etc.

In FIGS. 1 to 3, light was incident from the lower glass plate. However, the present invention does not limit the light incident side to the lower side.

[Brief explanation of the drawing]

FIG. 1 shows a panel of the photoelectric conversion device of this example. FIG. 2 is a longitudinal sectional view showing the manufacturing process of the photoelectric conversion device of this example. FIG. 3 is an enlarged vertical sectional view of the photoelectric conversion device of FIG. 1, which is the present embodiment.

Claims (1)

[Claims] 1. A first electrode provided on an insulating substrate, a non-single crystal semiconductor having at least a PIN junction provided on the electrode, and a second electrode provided on the semiconductor. A photoconversion device comprising a plurality of photoelectric conversion elements electrically connected to each other in series and disposed on the insulating substrate, wherein an end portion perpendicular to an end portion used for connection of the photoelectric conversion elements. An opening groove is formed in the first electrode along the end portion, the non-single crystal semiconductor is provided to cover the opening groove, and the end portion of the second electrode is located above the opening groove. Alternatively, a photoelectric conversion device characterized in that the device is located closer to the element region than above the groove.