JPH0419713B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for converting a non-single crystal semiconductor including an amorphous semiconductor having at least one PIN junction into a plurality of photoelectric conversion elements (also simply referred to as elements) provided on a transparent insulating substrate. The present invention relates to a photoelectric conversion device that can be connected in series to 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 a plurality of elements to 1/10 to 1/100 of the conventional mask alignment method.

The present invention provides an opening groove for separating the second electrodes of the first and second elements by separating and cutting the P or N type semiconductor layer of the semiconductor having the PIN junction under the electrode. The purpose is to prevent leakage current from occurring from the second electrode of the second element to the second electrode of the first element.

For this reason, the groove separating the second electrodes of the first and second elements is provided over the semiconductor of the first element to provide redundancy to improve manufacturing yield. It is said that

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.
By extending the second electrode of the second element to the surface or side surface of the
It is characterized by a reduction in the area required at the connecting part.

For this reason, the groove separating the semiconductors of the first and second elements is provided over the first electrode position of the first element to provide redundancy (margin) in manufacturing. There is.

Conventionally, in the mask alignment method, the connecting part required a width of 5 to 1 mm, but this is 1/10 to 1/100 of that width, 350 to 30 μm, preferably 200 to 50 μm.
m, the area for photovoltaic generation (referred to as effective area or effective area) of all panels used as photoelectric conversion devices in hybrid systems that require 10 to 50 stages of connecting parts is smaller than that of conventional
It is characterized by increasing the effective conversion efficiency from 75 to 50% to 97 to 90%, substantially improving the effective conversion efficiency by 10 to 20%.

In this invention, by using a laser beam scribing method, the address to be scribed is stored in advance in the memory of a computer (microcomputer) using the alignment mark as a reference. It is characterized by eliminating at once all causes of price increases and yield decreases in manufacturing, such as misalignment of masks, warping, and decreases in manufacturing yields relative 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-55-4994, JP-A-55-124274,
Further, patent application No. 54-90097/ filed by the present inventor
90098/90099 (filed on 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 simply 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, when using a metal mask, in a method that directly selectively creates a conductive layer or a semiconductor layer, the mask that provides this selectivity is used during film formation.
There may be a deviation of 0.5 to 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, in conventionally known screen printing methods, 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. I couldn't escape.

However, in the photoelectric conversion device of the present invention, particularly in the thin film type photoelectric conversion device, both the conductive layer for electrodes and the semiconductor layer, which are each thin film layer, are
It was found that the thickness was 500 Å to 1 μm, and that by using a laser scribing method, it could be manufactured without requiring any mask alignment.

As a result, instead of the conventional mask alignment process, the present invention uses no masks at all, so it is called a scribing process, but this scribing process is extremely simple and highly accurate due to the combined use of a microcomputer. This brings about a reduction in costs, which makes it possible to manufacture products for 500 yen/W.
The object of the present invention is to provide an extremely innovative photoelectric conversion device that is capable of converting yen/W.

Furthermore, in the present invention, in addition to using this laser scribing process, it is important that the alignment accuracy of the scribe lines has a degree of redundancy (margin). Therefore, the first electrode (lower side) between adjacent elements and the second electrode (upper electrode) of the other element are connected to the first electrode and its side or surface by a lead extending from the second electrode. By electrically connecting the scribe lines with each other, it was possible to provide redundancy in the positions of the open grooves of the scribe lines.

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. glass 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 selectively formed in the same manner 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
Between CTFs 13 requires a gap of 1 to 5 mm, for example 3 mm. Furthermore, the first electrode 37 and the second electrode 38 are electrically connected on the surface of 14, but this part must not be shot, including the spread of the second electrode 39 caused by blurring of the mask. Therefore, 6 is required between 1 and 5 mm, for example, 3 mm.
These three masks do not have self-aligning eyelashes, so the connecting part 12 has a width of 1 to 8 mm.
Typically, 4mm is required. Furthermore, if this is 1 mm or less, the mask alignment accuracy will be extremely strict, and the yield will be extremely reduced. If the distance between the connecting portions 12 is set to 5 mm or more, for example, if an element with a width of 15 mm (20 cm x 15 mm) and an end portion of 5 mm are manufactured in a size of 20 cm x 60 cm, only 20 stages can be connected in series. Also, between this connection
Even if it were 3 mm, there would be 33 stages, resulting in a total loss of 10 cm (area of 200 cm ² ) at the joints, and as a result, the effective area remained at 75% when the peripheral areas were taken into account.

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 to 86 to 97%, for example, 92%.

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 translucent substrate 1, for example a glass plate (for example, thickness 1.2 mm, length (left and right direction in the drawing) 60
cm, width 20cm). Furthermore, a transparent conductive film is applied over the entire top surface, such as ITO (1500Å) +
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.
~2000 Å) was formed by vacuum evaporation, LPCVD, plasma CVD, or spraying.

After this, a YAG laser processing machine (manufactured by Nippon Laser) is used to output 5 to 8 W from the bottom or top of this board.
The spot diameter is 30 to 70μmφ, typically 50μm.
mφ is irradiated 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 groove 13 formed by scribing is
Each of the first electrodes was completely cut and separated by a width of approximately 50 μm, a length of 20 cm, and a depth of 20 cm. 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 to form open grooves. After this, plasma CVD method or
A non-single crystal semiconductor 3 having a PN or PIN junction is formed by the LPCVD method to a thickness of 0.2 to 0.7 μm, typically 0.4 to
It was formed to a thickness of 0.5 μm. Typical examples are P-type semiconductor (SixC _1-x
or a P-type semiconductor (SixC _1-x ) -
N-type, P-type Si semiconductor - I-type SixGe _1-x semiconductor - N
Two PIN junctions and one PN made of type Si semiconductor
Tandem type PINPIN having a junction...This is a semiconductor 3 with a PIN junction.

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 is formed on the left side of the first open groove 13.
was formed by a second laser scribing process. This laser may be emitted either from below the glass 1 or from above this substrate.

Thus, the second open groove 18 is located on the side surface 8 of the first electrode.
9 was exposed. The side surface 9 of this second open groove is
It is sufficient that the electrode 37 is provided on the left side of the side surface 16 of the electrode 37, that is, it is characterized in that it is provided over the first electrode position of the first element. Furthermore, as shown in the conventional example, the present invention does not necessarily require exposing the surface 14 of the first electrode (see FIG. 1);
I removed all of CTF37 in the depth direction,
As a result, there is no practical problem even if the second electrode 38 is brought into close contact with the side surface 8 as shown in FIG. 2C. 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, a second electrode 38 on the back surface was formed on the upper surface as shown in FIG. 2C, and an opening groove 20 for cutting and separation in the third laser scribing method was provided.

This second electrode 38 is made of a transparent conductive film of 700~
It was formed from ITO (indium tin oxide) to a thickness of 1400 Å, silver was formed to a thickness of 300 to 3000 Å on the upper surface, and a double layer film of aluminum or aluminum and nickel was further 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. This ITO and silver capture the reflection of incident light 10 on the back side, and
This is for effective photoelectric conversion of long wavelength light of 800 nm. Furthermore, nickel is used to improve adhesion with the external extraction electrode 23. These are electron beam evaporation methods or plasma
The CVD method was used to form the semiconductor layer at temperatures below 300°C, which degrades the semiconductor layer.

This ITO also helps to prevent a decrease in reliability due to a chemical reaction between the semiconductor 3 and the back electrode 4, that is, to improve reliability.

A case is shown in which the back electrode is irradiated with a laser beam from above to cut and separate the second electrode to form an open groove 20. This laser beam slightly hollows out the semiconductor, especially the N or P type semiconductor layer that is in close contact with the upper surface 40, and
The occurrence of crosstalk (leakage current) due to residual metal or conductive semiconductor in the open grooves between the elements 11 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 one layer, for example.
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 hollow out the N-type semiconductor layer of the present invention and provide a semiconductor in the recess to prevent leakage current generation. Preferably, this hollowing out does not go beyond the I-type semiconductor layer and reach the CTF for the first electrode. The present invention uses a laser beam to remove not only the second electrode but also the P- or N-type semiconductor layer below the second electrode, and further stops it in the middle of the I-type semiconductor layer that is 0.2 μm or more below the second electrode. Therefore, it is industrially important to be able to provide a margin for the thickness of the I-type semiconductor layer in the process of forming the groove portion 20.

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. These were filled with an organic resin 22 such as polyimide, polyamide, Kapton or epoxy.

Thus, for the irradiation light 10, each element has a width of 14.35 mm on a substrate (60 cm x 20 cm) as in this example.
Width of connecting part 150μm, width of external lead electrode part 10
mm, and the peripheral area is 4 mm, so there are essentially 40 steps within 580 mm x 192 mm, and the effective area (192 mm x 14.35 mm x 40 steps)
1102 cm ² or 91.8%). If the resulting segment has a conversion efficiency of 10.6%,
At panel 9.7% (AM1 (100mW/cm ² ))
It was possible to have an output power of 11.6W.

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.

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. For this reason, it has become possible to omit the silicon nitride film coating 21 in FIG. 2D for general consumer use.

Furthermore, since the electrical connection between the first electrode and the second electrode can be made on both sides of the first electrode, the area required for this contact part is sufficiently reduced to less than 1/10 compared to the conventional method. As a result, the effective area of the panel could be improved.

FIG. 3 is a longitudinal cross-sectional view and a plan view (end portion) showing the most typical positional relationship of the grooves formed in three laser scribing steps. Numbers etc. are the same as in FIG. 2.

FIG. 3A shows the first open groove 13, the first element 31,
It has a second element 11 and a connecting portion 12.

As is clear from the drawing, the fourth groove 13' not only cuts the transparent conductive film but also slightly gouges the substrate 1. Further, the fifth groove 18' is provided by cutting both the semiconductor 3 formed to cover the electrode 2 of the first element and the first electrode 2, and both of them are removed. Furthermore, a conductor 4 constituting a second electrode is provided thereon. Therefore, the first electrode 2 of this first element 31 and the second element 1
1 and the second electrode 4' at the connecting portion 12.
The first element and the second element are electrically connected at the side surface 8 of the first electrode 2 by a conductor extending from the electrode.
elements are connected in series with each other.

In this way, in addition to eliminating the possibility that the upper and lower electrodes will shoot each other at the edge of the substrate 1, the formed three-layer photoelectric conversion device can be connected in series and can be multi-layered as a multi-layered panel. can be done.

Furthermore, in the drawings, at least one PIN junction is shown.
Here, one SixC _1-x (0<x
<1) P type 42-I type Si43-microcrystallized N type
A semiconductor having one PIN junction made of Si44 is provided. This semiconductor, especially the N-type semiconductor 4
4 through the third open groove 2 shown in the I-type semiconductor 43
0 has the depth of the groove. In this way, the second electrodes 4 of each of the first and second elements 31 and 11 are electrically cut and separated, and the leakage between these electrodes is also reduced to 10 μA/cm (meaning on the order of 10 μA per 1 cm width). I was able to make it smaller.

To improve long-term reliability, a coating film of silicon nitride film may be formed on the upper surface by plasma CVD as shown in FIG. 2B. Furthermore, this third open groove is provided across the first element 31 side, and has a scanning margin of the laser scribing machine in that direction, so that, for example, this scribing spot is 75 μm in diameter in the left direction and 30 μ in the right direction.
It had a width of 105 μm. Considering that the scribing accuracy is generally ±15 μm, it can be seen that a sufficient amount can be produced.

FIG. 3B shows a plan view, and at its end (lower side in the drawing) fourth, fifth and sixth open grooves 13',
18' and 20' are provided. In order to further reduce leakage in this direction, the structure is such that the semiconductor 3 covers the first electrode 2, thereby reducing the shot between the first and second electrodes.

In this drawing, the first and second opening widths are 50~
30 μm, the third opening width is 75 to 50 μm (in metal, the width is a little wider because the laser beam conducts better in the lateral direction), and the width of the connecting part can be 150 to 100 μm. Ta.

FIG. 4A shows a case where the second laser scribing step is performed from above the substrate in the connecting portion 12, and a portion of the CTF of the first electrode remains in the open groove 16.

FIG. 4B shows the first open groove part 13 and the second open groove part 1.
8 are closest to each other, the side surface 16 of the first electrode and the side surface 9 of the second electrode are insulated by the semiconductor 3, and the third groove 20 is insulated from the side surface 9 of the second electrode.
The width provided over the first element side is reduced from the right side in the figure to minimize the loss area required for the connecting portion, and it is possible to have a connecting portion with a width of 100 to 60 μm.

The spot layer of the YAG laser with more than 3 outputs
~5W (30μm) and 5~8W (50μm) are used, 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. 5 is an enlarged view of the external lead-out electrode section when photoelectric conversion devices smaller than a large panel for a calculator or the like are to be mass-produced at the same time.

FIG. 5A 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, the electrode 47
The groove 13' is provided to prevent the pad 49 from being shot even if the pressure is too strong and the pad 49 penetrates the first electrode 2 and semiconductor 3 underneath. Further, the outer portion is cut and separated by open grooves 18' and 20'. Furthermore, in FIG. 5B, another pad 48 connected to the first electrode 2 on the lower side is connected at 18'' with a second electrode material. are in contact and electrically connected to the outside. Again, the open grooves 18", 18, 2
The pad 48 is electrically isolated from other photoelectric conversion devices by 0'', 20, and by cutting the glass between these devices in a post-process, it is possible to use a matching mask in one panel. It has the feature that it is possible to create a large number of photoelectric conversion devices without using a 20cm x 60cm panel.For example, a 6cm x 1.5cm photoelectric conversion device (for a calculator) can be made using a 20cm x 60cm panel.
If you try to make , 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, these panels, for example, 6 or 4 pieces of 40cm x 20cm or 60cm x 20cm, can be assembled in series and parallel in an aluminum sash frame to create a package of 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 of laminated glass by laminating another glass plate with Seaflex on 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 to 5, 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 an enlarged view of a vertical cross-sectional view and a plan view of the photoelectric conversion device of the present invention. 4 and 5 are partially enlarged vertical cross-sectional views of another photoelectric conversion device of the present invention.

Claims (1)

[Claims] 1. A plurality of photoelectric conversion elements each having a non-single crystal semiconductor having a first electrode on an insulating substrate and at least one PIN junction on the electrode, and a second electrode on the semiconductor. At an end perpendicular to the end used to connect the photoelectric conversion elements of the photoelectric conversion device which are electrically connected to each other in series and arranged on the insulating substrate, a first The non-single crystal semiconductor is provided to the outside of the first electrode so as to cover the open groove formed in the electrode, and an open groove is provided to the semiconductor on the outside that covers the open groove. In addition, a photoelectric conversion device characterized in that the non-single crystal semiconductor remains on the outside of the photoelectric conversion device. 2. Forming a first conductive film constituting a first electrode on an insulating substrate, and cutting and separating the first conductive film into multiple segments using a laser beam to form a first groove. and forming a fourth open groove perpendicularly to the first open groove using a laser beam;
forming a non-single crystal semiconductor layer having at least one PIN junction over the conductive film and covering the first and fourth grooves; A second open groove is formed by cutting and separating the non-single crystal semiconductor into a plurality of segments using a laser beam, and a fifth open groove is formed perpendicularly to the second open groove using a laser beam. The first conductive film and the second conductive film are formed by forming the first conductive film on the outside covering the first electrode and forming the second conductive film so as to cover the non-single crystal semiconductor. After connecting with the conductive film,
configuring a plurality of photoelectric conversion elements by a step of cutting and separating the second conductive film, or the conductive film and the non-single crystal semiconductor below it with a laser beam to form a third groove; A method for manufacturing a photoelectric conversion device, characterized in that the plurality of photoelectric conversion elements are electrically connected in series and formed on the same insulating substrate.