JPH0415631B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides electrical conversion of a plurality of photoelectric conversion elements (also simply referred to as elements) in which a non-single crystal semiconductor including an amorphous semiconductor having at least one PIN junction is provided on a transparent insulating substrate. The present invention relates to a photoelectric conversion device that is connected in series and can generate a high voltage, and a method for manufacturing the same.

The present invention is characterized in that a laser scribing method is used to reduce the area required for connecting multiple elements to 1/10 to 1/100 of the conventional mask alignment method.

In this invention, the second groove for electrically connecting the first and second elements is removed by removing the non-single crystal semiconductor having the PIN junction and the first electrode therebelow. A second electrode of a second element is connected to a side surface of a first electrode of the element, and in this case, the second groove is provided to extend inside the second electrode of the first element. By this, the first element, the second
The purpose of this invention is to achieve more complete electrical isolation between the respective first electrodes of the elements.

For this reason, the groove separating the second electrodes of the first and second elements is provided over the semiconductor of the first element, thereby providing redundancy to improve manufacturing yield. There is.

In this invention, the electrical connection at the connecting portion is made using a transparent conductive film (CTF) that constitutes the first electrode of the first element.
The second electrode of the second element is extended to the side surface of the device and used in close contact with the side surface of the device, thereby reducing the area required at the connecting portion.

For this reason, the groove that separates the semiconductors of the first and second elements is provided over the first electrode position of the first element to reduce manufacturing redundancy (margin) due to fluctuations in LS scanning. It is characterized by giving.

Conventionally, in the mask alignment method, the connecting portion required a width of 5 to 1 mm, but by making this width 1/10 to 1/100 of that, 350 to 30 μm, preferably 200 to 50 μm, this connecting portion can be made wider. In a hybrid system that requires 10 to 50 stages, the area for photovoltaic generation (referred to as effective area or effective area) of all panels used as photoelectric conversion devices is 75
It is characterized by increasing the effective conversion efficiency from ~50% to 97~90%, substantially improving the effective conversion efficiency by 10~20%.

In this invention, by using a laser beam scribing method, the address to be scribed using the alignment mark as a reference is stored in advance in the memory of a computer (microcomputer), which is not necessary in the conventional mask alignment method. It is characterized by eliminating at once all causes of price increases and yield decreases in manufacturing, such as mask misalignment, warping, and decreases in manufacturing yields due to alignment accuracy.

Conventionally, many examples of photoelectric conversion devices (hereinafter simply referred to as devices), that is, devices in which a plurality of elements are arranged on the same substrate and are integrated or hybridized, are known.

For example, JP-A No. 55-4994, JP-A No. 55-124274, and Japanese Patent Application No. 54-90097 filed by the present inventor.
90098/90099 (July 16, 1972) is known.

For example, in the patent application filed by the present inventor, the semiconductor is a SixC _1-x -Si heterojunction, which is different from the case where other amorphous silicon semiconductors are used, and furthermore, this semiconductor has a structure other than an amorphous structure. It is characterized in that it is an integrated or hybridized non-single crystal semiconductor having at least one PIN junction to which hydrogen or halogen elements containing a microcrystalline structure are added.

However, in these conventional inventions, as shown in FIG. 1, which is a vertical cross-sectional view, all of them employ a mask alignment method, which results in insufficient alignment accuracy and requires a large area for the connecting portion.

For example, in the case of using a metal mask, in a method for directly selectively producing a conductive layer or a semiconductor layer, the mask that provides this selectivity is used during film formation.
There may be a deviation of 3 mm. Furthermore, since a film component is formed on this mask, the mask becomes contaminated, and the mask is warped, making the peripheral edge of the film formed unclear, resulting in crosstalk (leakage current) between adjacent electrodes. It had many drawbacks, such as being a factor in

Furthermore, conventionally known screen printing methods and the like are methods in which conductors or semiconductors formed entirely on a substrate are independently and selectively etched away using a mask. However, in this method, the process is extremely time consuming, including the process of aligning the mask for screen printing, the process of coating the resist, the process of baking and solidifying, the process of etching the conductor or semiconductor, and the process of removing the resist, which increases the manufacturing cost. could not be avoided.

However, in the photoelectric conversion device of the present invention, particularly in the thin film type photoelectric conversion device, each of the thin film layers, the conductive layer for electrodes or the semiconductor layer, is
It has a thickness of 500 Å to 1 μm, and by using a laser scribing method, it has become possible to manufacture it without the need for mask alignment.

As a result, in place of the conventional mask alignment process, in the present invention, the scribing process is called a scribing process because no masks are used, but this scribing process is extremely simple and highly accurate due to the combined use of a microcomputer. This resulted in a reduction in manufacturing costs. Therefore, it is possible to manufacture products for 500 yen/W, and by expanding the manufacturing scale, 100 yen/W is possible.
By providing an extremely innovative photoelectric conversion device that can be sold for up to 200 yen/W.

Furthermore, in the present invention, 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 it to the scribe line, it was possible to provide redundancy in the position of the open groove of the scribe line.

A conventional example and the structure of the present invention will be described below according to the drawings.

FIG. 1 is a longitudinal sectional view of a conventionally known photoelectric conversion device using a mask alignment method.

In the drawing, a translucent substrate (e.g. Geiss plate) 1
A transparent conductive film (CTF) constituting the first electrode is placed on top.
) are selectively formed by the first mask alignment step. Further, the semiconductor layer 3 is similarly selectively formed by a second mask alignment step. Further, a second electrode 4 is provided by a third mask alignment step.

In FIG. 1, there is a connecting part 12 between the elements 11 and 31, and in the connecting part, the semiconductor layer 3 covers one side surface 16 of the CTF, and the semiconductor layer 3 does not cover the surface 14 of the other CTF. In order to
During CTF 13, a distance of 1 to 5 mm, for example 3 mm, is required. Furthermore, the first electrode 37 and the second electrode 3
Since the second electrode of No. 8 must not be shot, including the spread caused by the blurring of the mask,
For example, 6 is required between 5mm and 3mm. These 3
Since two masks do not have any self-alignment properties, the connecting portion 12 is typically 1 to 8 mm.
mm is required. Furthermore, if this is less than 1 mm, the mask alignment accuracy will be extremely strict, and the yield will be extremely reduced. If the distance between the connecting parts 12 is 5 mm or more, for example, 20 cm x 60
If we try to fabricate an element with a width of 15 mm (20 cm x 15 mm) and a terminal of 5 mm in cm, we can only connect 20 stages directly. In addition, even if the distance between the connecting parts is 3 mm, there are 33 stages, which results in a total loss of 10 cm (area of 200 cm ² ) at the connecting parts, and as a result, the effective area remains at 75% when the peripheral area is taken into account. It was on.

The object of the present invention is to provide an extremely innovative photoelectric conversion device that eliminates the complexity of such a process and can increase the effective area by 86 to 97%, for example, to 92%.

In addition, when forming the area between the second electrodes 4 (6) or between the semiconductors 3 (part of 7 and 6), the surface in contact with the mask is not flat but has unevenness due to the pattern, which makes it even worse. The blur of the mask became wider and the area of the connecting part became wider.

Details of the embodiment will be shown below with reference to the drawings.

FIG. 2 is a longitudinal sectional view showing the manufacturing process of the present invention.

In the drawing, a substrate having an insulating surface, such as a transparent substrate 1, ie, a glass plate (for example, thickness 1.2 mm, length (in the left-right direction in the drawing) 60 cm, and width 20 cm) was used.
Furthermore, a transparent conductive film such as ITO (approximately 1500 Å) + SnO ₂ (200 to 400 Å) or a transparent conductive film whose main component is tin oxide doped with a halogen element (1500 to 2000 Å) is applied over the entire upper surface. ) was formed by vacuum evaporation, LP CVD, plasma CVD, or spraying. After that, a YAG laser processing machine (manufactured by Nippon Laser) applies an output of 5 to 8 W to the bottom or top of this substrate, and irradiates a spot diameter of 30 to 70 μm (typically 50 μm) by controlling a microcomputer. By this scanning, an open groove 13 for a scribe line was formed, and a first electrode 2 was produced between each element.

The open grooves 13 formed by scribing were approximately 50 μm wide, 20 cm long, and 20 cm deep, completely cutting and separating each of the first electrodes. For this reason, as is clear from the drawings, a portion of the substrate 1 was sometimes gouged out (a recess was formed). Thus, the width of the first element 31 and the second element 11 was set to 10 to 20 mm.

Using the above laser scribing method, the CTF 2 constituting the first electrode was cut and separated into a plurality of rectangular regions (each serving as the first electrode of each element) to form open grooves. Thereafter, a non-single crystal semiconductor layer 3 having a PIN junction was formed on the upper surface by plasma CVD or LP CVD to a thickness of 0.2 to 1.0 μm, typically 0.4 to 0.5 μm. A typical example is P-type semiconductor (SixC _1-x X=0.850~150Å)-I
Type amorphous or semi-amorphous silicon semiconductor (0.4~0.5μm) - N type microcrystal (100~
200 Å), or P-type semiconductor (SixC _1-x ) - I-type, N-type, P-type Si semiconductor - I-type
SixGe _1-x semiconductor - two types of N-type Si semiconductor
Tandem type with PIN junction and one PN junction
PINPIN: PIN junction semiconductor 3.

The non-single crystal semiconductor 3 was formed to have a uniform thickness over the entire surface. Furthermore, as shown in FIG. 2B, a second open groove 18 was formed on the left side of the first open groove 13 with a width of 50 μm and a distance of 100 to 500 μm by a second laser scribing process. . The laser may be applied either from below the glass 1 or from above the substrate.

The second open groove 18 thus exposed the side surfaces 8, 9 of the first electrode. The presence of the right side surface 9 of the first electrode formed by the second groove causes the first electrode of the first element on the left side of the side surface 16 of the first electrode 37 to
It is characterized by being provided over the electrode positions. Then, 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.
By doing so, the first electrode 37 of the first element
A part of it remains on the right side of the second open groove. If there is no such residual area, the high heat of the laser light (~2000
CTF2 is much easier to process than the CTF2, so the semiconductor filled in the first groove 13 is blown away. Therefore, isolation between the first electrodes of the first and second elements becomes impossible. For this reason, it is extremely important that the second groove is provided inside the first electrode, as shown in FIG. 2B. The CTF remaining in this portion 9 had a width of 50 to 500 μm.

Furthermore, as shown in the conventional example, the present invention
It does not expose the surface 14 of the electrode (see Figure 1), but the laser beam is a little too strong at 5 to 10 W and removes the entire CTF 37 in the depth direction, resulting in a second layer on the side surface 8. Second electrode 3 in figure C
There is no practical problem even if 8 are placed closely together. That is, it is extremely important for the industrial application of the present invention that a margin can be given to the intensity of the output pulse of the laser beam.

In FIG. 2, a second electrode 4 on the back surface is further formed on this top surface as shown in FIG. 2C,
Furthermore, a third groove 20 for cutting and separation in the third laser scribing method was provided.

This second electrode 4 is made of a transparent conductive film with a thickness of 700 to 1400
It is made of ITO (indium tin oxide) to a thickness of 300 Å, and a reflective metal silver is coated on the top surface.
Formed to a thickness of ~3000 Å. Furthermore, a two-layer film of aluminum or aluminum and nickel was formed on the upper surface. For example, it has a three-layer structure of ITO of 1050 Å, silver of 1000 Å, and nickel of 1500 Å. The ITO and silver are used to promote reflection of incident light 10 on the back surface side and to effectively photoelectrically convert long wavelength light of 600 to 800 nm. Furthermore, nickel is used to improve adhesion with the external extraction electrode 23. These were formed using an electron beam evaporation method or a plasma CVD method at a temperature of 300° C. or lower, which does not deteriorate the semiconductor layer.

This ITO is also useful for preventing a decrease in reliability due to a chemical reaction between the semiconductor 3 and the back electrode 4, that is, improving reliability.

The back electrode is irradiated with a laser beam from above to cut and separate the second electrode to form a third open groove 20.
(width 50 μm) is shown. This laser light is applied to N or P which is in close contact with the semiconductor, especially the top surface.
40 Adjacent first element 31 Second element 1
The occurrence of crosstalk (leakage current) due to residual metal or conductive semiconductor in the open grooves between 1 and 2 was prevented.

In particular, this semiconductor 3 has a P-type semiconductor layer 42, an I-type semiconductor layer 43, an N-type semiconductor layer 44, and, for example, one
It has a PIN junction, and this N-type semiconductor layer has a microcrystalline or polycrystalline structure. Its electrical conductivity is 1~
When the conductivity is as high as 200 (Ωcm) ^-1 , it is extremely important to scoop out and remove the N-type semiconductor layer of the present invention and provide a semiconductor in the recess to prevent leakage current generation. This gouging does not have to go beyond the I-type semiconductor layer and reach the CTF for the first electrode. According to the present invention, not only the second electrode can be used to form grooves using laser light, but also the work process for forming the groove portion 20 can have a margin corresponding to the thickness of the I-type semiconductor layer that is 0.2 μm or more below the second electrode. Industrially important.

In this way, as shown in FIG. 2C, a photoelectric conversion device in which a plurality of elements 31 and 11 were connected in series at a connecting portion could be manufactured.

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 was formed to a thickness of 500 to 2000 Å to prevent leakage current between each element. Further, an external lead terminal 23 is provided at the peripheral portion 5. An organic resin 22 such as polyimide, polyamide, Kapton or epoxy was filled.

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.
The effective area (192 mm x
14.35 mm x 40 stages, 1102 cm ² or 91.8%). As a result, if the segment has a conversion efficiency of 10.6%, the panel has a conversion efficiency of 9.7% (AMI (100
It was possible to have an output power of 11.6W at mW/cm ² ).

This is the same as when using the conventional mask matching method.
This is an extremely significant effect compared to 55% (for 40 stages). 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.

With the structure of the present invention, when forming the first open groove, the second open groove, and the third open groove, the base surface is flat and laser processing can be performed uniformly, so that the processing dimensional accuracy of the connecting portion can be improved. Furthermore, it was possible to reduce the area of the connecting portion (non-power generating portion).

As is clear from the above examples, the N or P type semiconductor layer under the second electrode was also removed at the same time by cutting and separating using the laser scribing method to form the second electrode according to the present invention. Leakage current between two electrodes is less than 10 ^-3 mA/cm
We were able to lower it to 10 ^-9 A/cm. Therefore, for general consumer use, it has become possible to omit the silicon nitride film coating 21 shown in FIG. 2D.

Furthermore, regarding the connection part, since the first electrode is connected to the second electrode of the adjacent element on the side surface, the area required for this connection part (contact part) is reduced to 1/10 or less compared to the conventional method. As a result, the effective area of the panel can be improved.

The spot layer of the YAG laser with more than 3 outputs
~5W (30μm) and 5~8W (50μm), but by further reducing the spot diameter based on the technical concept, this connection part can be made smaller and the effective area as a photoelectric conversion device can be further increased. It has an inventive step in that it can be improved.

FIG. 3 is an enlarged view of the externally drawn electrode portion when photoelectric conversion devices smaller than a large panel for a calculator or the like are to be manufactured in large quantities at the same time.

FIG. 3A corresponds to FIG. 2, but the external lead-out electrode section 5 has a pad 49 that contacts the conductive rubber electrode 47, and this pad 49 is connected to the second electrode (upper electrode) 4. are doing. At this time, electrode 4
The groove 13 is provided to prevent the pad 49 from penetrating the first electrode 2 and the semiconductor 3 thereunder due to too strong pressure. Further, the outer portion is cut and separated by open grooves 18' and 20'. Further, in FIG. 3B, another pad 48 connected to the first electrode 2 on the lower side is connected at 18" by a second electrode material. Furthermore, the pad 48 is connected to the conductive rubber electrode 46. are in contact and are electrically connected to the outside. Again, the open grooves 18', 18'', 20'',
20, the pad 48 is electrically isolated from other photoelectric conversion devices, and by cutting the glass between these devices in a post-process, a large number of sheets can be formed in one panel without using a matching mask. It has the feature of being able to make photoelectric conversion devices of For example, if you try to make a 6cm x 1.5cm photoelectric conversion device (for a calculator) using a 20cm x 60cm panel, you will find that you can make 130 calculator solar cells at once. That is, the photoelectric conversion device is covered with the organic resin mold 22 except for the electrode parts 5 and 45, and if a small power solar cell is to be made after this, it can be cut using a glass cutter. Furthermore, this panel can be packaged by combining 6 or 4 pieces of 40cm x 20cm or 60cm x 20cm in series within an aluminum sash frame, making it 120cm x 40cm.
It is possible to install a high power panel that meets the NEDO standard.

In addition, this NEDO standard panel is made by laminating another glass plate with Seaflex to the reflective surface side (upper side in the drawing) of the photoelectric conversion device of the present invention, and the photoelectric conversion device is placed between them. It is also effective to increase mechanical strength.

In FIGS. 2 and 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 drawings]

FIG. 1 is a longitudinal sectional view of a conventional photoelectric conversion device. FIG. 2 is a longitudinal sectional view showing the manufacturing process of the photoelectric conversion device of the present invention. FIG. 3 is a vertical sectional view showing an enlarged external lead electrode portion of another photoelectric conversion device of the present invention.

Claims (1)

[Claims] 1. A plurality of photoelectric conversion elements each having a first electrode on a substrate having an insulating substrate surface, a non-single crystal semiconductor having at least one PIN junction on the electrode, and a second electrode on the semiconductor. Regarding the structure in which the plurality of photoelectric conversion elements are electrically connected in series, and the photoelectric conversion element at one end of the plurality of photoelectric conversion elements is connected to the photoelectric conversion element at the other end, and an external extraction electrode portion is provided for each, the photoelectric conversion element at one end of the plurality of photoelectric conversion elements is The external extraction electrode portion extending from the second electrode is electrically separated from the non-single-crystal semiconductor and the first electrode of the photoelectric conversion element at one end on the substrate below by an opening groove. The external lead electrode section is provided with the same conductive material as the first electrode, and is connected to the photoelectric conversion element at the other end, and is provided between the photoelectric conversion element at the other end. An external extraction electrode portion made of the same material as the second electrode connected to the first electrode of the photoelectric conversion element at the other end is provided by the open groove, and the semiconductor and the first electrode are provided under the second electrode. A photoelectric conversion device characterized in that the same conductive material is provided on the substrate, and the external lead electrode part is separated from the second electrode of the photoelectric conversion element provided at the other end by an open groove. .