JPS63133578A - Semiconductor device - Google Patents

Abstract

PURPOSE:To enhance the collecting efficiency of the long-wavelength light and, in its turn, to enhance the conversion efficiency by a method wherein a laser annealing-process excluding a connecting part is executed before or after the formation of an N-type or a P-type semiconductor layer as a process after the formation of an I-type semiconductor. CONSTITUTION:A first conductive film 2 is formed on the whole surface of a glass substrate 1; a first opening 13 is made by means of a YAG-laser processing machine; first electrodes 15 are formed in element regions 31, 11. After that, an unsingle crystalline semiconductor which generates photovoltaic power by light irradiation, i.e., an unsingle crystalline semiconductor layer 3, with a thickness of 0.3-3.0mum, which contains a PIN junction, an NIP junction, or a PI junction or an NI junction and contains an amorphous silicon semiconductor doped with hydrogen or a halogen element, is formed on the assembly; during the process, the irradiation width is made equal to the width of the device regions 11, 31; the assembly is annealed by light; thick regions 35-2, 35'-2, partially, on the side of away-from-the-surface electrodes in an I-layer out of the unsingle crystalline semiconductor are made to crystallize.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application of the Invention The present invention is directed to a method in which a non-single crystal semiconductor including an amorphous semiconductor having at least one junction capable of generating photovoltaic force upon irradiation with light is provided on a substrate having an insulating surface. The present invention relates to a photoelectric conversion device that is capable of generating high voltage and has a plurality of photoelectric conversion elements (also simply referred to as elements) electrically connected in series.

"Prior Art" Conventionally, amorphous semiconductors are known as non-single crystal semiconductors to which hydrogen or halogen elements are added. However, since such semiconductors have an amorphous structure and do not actively use crystallinity, the carrier depletion layer of the I-type semiconductor layer in the PIN junction is as narrow as 0.3μ or less, and the A
Ml, 5 (The depletion layer became even shorter when irradiated with light at about 100 mW/cm, resulting in deterioration.

"Problems to be Solved by the Present Invention" Active I which generates electrons and holes by light irradiation is applied to non-single crystal semiconductors including such amorphous semiconductors.
There is a need to improve the conversion efficiency by promoting crystallization in the semiconductor region to improve the collection efficiency, especially for long wavelength light. Furthermore, in photoelectric conversion devices with PIN junctions, the width of the depletion layer in the ■-type semiconductor is increased to 1μ or more, and the connection parts for integration are made of a high-resistance amorphous structure without crystallization. There is a need to prevent leakage from occurring through the semiconductor in this region by allowing the region to remain as it is.

``Means for Solving the Problem'' The present invention applies pulsed intense light (with a wavelength of 400 nm or less) to a non-single crystal semiconductor from the back electrode side before or after forming an N-type or P-type semiconductor layer. ~100ns)
By irradiating the 2-type semiconductor layer or this I-type semiconductor layer and the N or P-type semiconductor layer on the back side adjacent thereto, crystallinity can be promoted while preserving hydrogen or halogen elements inside.

As a result, in semiconductors whose main component is silicon, 1
．． 3-1.6 eV and 1.7-1.
The energy band width may be narrower than 8 eV.

Therefore, it has become possible to improve the collection efficiency of long wavelength light.

In particular, the present invention is capable of transmitting strong pulsed light from an excimer laser using KrF or After the semiconductor was formed, the crystallinity of the type semiconductor was promoted by irradiation from the back side, and so-called photo-annealing was performed. For this reason, a wavelength of 400 nm or less, which has a relatively large light absorption coefficient of the semiconductor, was used as the light.

The present invention is based on the patent layer (Japanese Patent Application No. 59-181) by the inventor.
This is a further improvement of 097 Semiconductor Device (filed on August 24, 1980).

In the present invention, the accompanying increase in electrical conductivity due to this photoannealing must not allow leakage at the periphery. Therefore, in an integrated structure, isolation at the connecting portion must not be hindered. Therefore, in the present invention, this optical annealing was performed only on the region constituting the photoelectric conversion element.

"Effect" As a result, the crystallization promoting region obtained by laser annealing does not affect the isolation region between each cell (element) or its outer periphery. It has the advantage of being able to be completed without any extra steps.

The arrangement, size, and shape of elements in the device of the present invention are determined by design specifications. However, in order to simplify the content of the present invention, in the following detailed description, the first electrode on the lower side (substrate side) of the first element and the second electrode of the second element disposed on the right side thereof will be described. The pattern is based on the case where the electrodes (on the semiconductor, that is, on the back side away from the substrate) are electrically connected in series.

This defined position is irradiated with an excimer laser using, for example, KrF or XeC1, for example, a wavelength of 248 nm. In the present invention, a semiconductor is formed on a transparent glass substrate, and a distance of 400 nm from the back surface side to the light irradiation side of the top surface.
The following laser beam annealing was performed, and the yield was increased from about 60% to 87% without increasing the manufacturing process.
The object of the present invention is to provide an innovative method for manufacturing a photoelectric conversion device that can increase the performance of the photoelectric conversion device.

The details of the invention are shown below in accordance with the drawings.

"Example 1" FIG. 1 is a longitudinal sectional view showing the manufacturing process of the present invention.

In FIG. 1(A), a substrate having an insulating surface, such as a glass substrate (1), is shown (in the left-right direction in the drawing).
A size of 10 cm and a width of 10 cm was used. Furthermore, on this top surface,
A first conductive film (2) was formed over the entire surface using a transparent conductive film to a thickness of 0.1 to 0.5 μm.

This transparent conductive film (2) is a transparent conductive film whose main component is tin oxide to which a halogen element such as fluorine is added, or ITO (tin oxide indium) (500 to 5000
(typically 500 to 1,500 people) were formed by sputtering or spraying.

After this, a YAG laser (wavelength 1.
06μm (pulse width 80ns) processing machine (Nippon Denki type))
By adding an average output of 0.3 to 40 mm (focal length 40 mm), a laser beam with a diameter of 5 mmφ is focused, and a spot diameter of 20 to
A laser beam of 70 μφ, typically 40 μφ, is controlled by a microcomputer and irradiated with a laser beam from above, and by scanning, a first groove (13) for a scribe line is formed, and each element region (31), ( 11) A first electrode (15) was produced by laser scribing (referred to as LS).

The open grooves (13) formed by LS had a width of about 50 μm and a length of 10 cm, and the depths were completely cut and separated to form the first electrodes.

Thus, the first element (31) and the second element (11
) The width of the area constituting the area is 5 to 40 mm, for example 10 mm.

After that, a non-single crystal semiconductor, that is, a PIN junction, a NIP junction, which generates a photovoltaic force by light irradiation, is formed on the upper surface by plasma CVD, photoCVD, or LPCVD.
Alternatively, the non-single crystal semiconductor layer (3) having a PI junction or NI junction and doped with hydrogen or a halogen element has a minimum oxygen concentration of 5 XIO"cm-" or less in a ■-type semiconductor, and its thickness is 0.3-3.0μ typically 1.5μ
was formed.

The first typical example is when light is irradiated from the substrate side, so it is a P-type (SixC, 0<x<1) semiconductor (
Approximately 200 people) - Type I amorphous silicon semiconductor (approximately 1
．． 5μ) - a non-single-crystalline semiconductor (with one PIN junction) consisting of a semiconductor with N-type microcrystals (approximately 500 microcrystals)
3) was formed to have a uniform thickness over the entire surface.

In the second representative example, a non-single crystal semiconductor (3) having one PI junction having a P-type semiconductor and a ■-type amorphous semiconductor is formed over the entire surface.

Furthermore, an outline of excimer laser light annealing that emits ultraviolet light with a wavelength of 400 nm or less in the method of the present invention will be shown.

The semiconductor to be irradiated is shown in FIG. 1(A). A semiconductor before (after forming a PI junction, i.e., second representative example) or after forming an N-type semiconductor constituting a PIN junction (i.e., after forming a PIN junction, i.e., first representative example) is used as an object in a photo-annealing process. It was used as

This object was stored in a vacuum or in a hydrogen atmosphere, and pulsed light was irradiated from the outside through a synthetic quartz window.

Excimer pulse laser light was used with the irradiation area of the light source being 120 mm. In particular, this width was the same as the area constituting the element, and the same area was irradiated once or repeatedly pulsed light was irradiated less than 10 times. As an operation, the irradiation part was moved to optically anneal all the regions that constitute the element.

Here, an excimer laser oscillator manufactured by Kesnack was used.

This laser beam is focused by a lens, has a rectangular shape, and has a length of 10m.
Pulsed light with an area of m x 12 mm (repetition frequency 3
0Hz to 300Hz) was used. This irradiation width was made to match the width of the element regions (11) and (31) in FIG.

This irradiation light (25) was irradiated onto a substrate moving at a constant speed on the irradiation surface.

(As a result, it was possible to crystallize a region with a depth of 0.1 to 0.4 μm in a part of the back electrode side of one layer in the non-single-crystal semiconductor.The fact of this crystallization was found by performing laser Raman spectroscopy after this step.In addition, the annealing of the method of the present invention has a pulse width of 10 to 5.
Because the light pulse annealing is as short as 0 nanoseconds, there is almost no possibility of degassing the hydrogen or halogen elements already contained during crystallization. In addition, since crystallinity or orderliness is promoted by photoannealing, photodegradation characteristics are reduced, and in addition, the width of the depletion layer in one layer between PIs is 1 to 3μ, compared to 0.3μ in an amorphous PIN junction. It had the double feature of being able to be stretched. For this reason, the optimum thickness of one layer is determined by using only amorphous semiconductor in one layer.
Because it has a composite structure with a semiconductor that has crystallization properties, it can be made thicker to 0.5 to 2.0 μm, and short wavelength light can be used in the amorphous silicon semiconductor region (35-1). 35'-1), and long wavelength light is absorbed by the polycrystalline silicon semiconductor region (35-2).
, (35'-2) makes it possible to perform photoelectric conversion over a wide range of wavelengths. As a result, the current as a photoelectric conversion device can be increased.

This laser beam annealing is performed on the regions (35-2) (31) and (11) that constitute the device in FIG. 1(C).
.

(35'-2). The region constituting the connecting portion (4) is a high-resistance semiconductor, especially an amorphous semiconductor, and the semiconductor (34) below the (20) is connected to the electrode (
39) and (39°) to ensure that there is no leakage.

Furthermore, this laser annealing is applied to both ends of the device in the width direction (
It was placed 1 to 2Il111 inward from the end in the front-rear direction of the drawing, and did not reach both ends. As a result, the region (31) where the amorphous semiconductor constitutes the element, (
11) is polycrystalline (35-2), (35'
-2) remains all around the outside. In other words, the outer periphery of the region constituting the element is surrounded by a high-resistance amorphous semiconductor, so that the upper and lower electrodes at the periphery of the semiconductors (35-2) and (35'-2) It was possible to prevent leakage between the two, that is, a decrease in series resistance in terms of an equivalent circuit.

Furthermore, in the first example of the present invention, after this laser annealing, as shown in FIG. The open groove (14) was formed by the second LSI process.

In this drawing, the first and second open grooves (13), (1
4) are shifted by 100μ between the centers.

The second open groove (14) thus forms a side surface (8) of the first electrode.
exposed.

In the second example, since only a PI junction was formed, an N-type semiconductor was formed thereon by plasma CVD to form a PIN junction semiconductor. Subsequently, the open grooves (14) were formed as described above.

In FIG. 1, a second surface conductive film (5) was further formed on this upper surface as shown in FIG. 1(C).

Furthermore, after this, isolation was performed by cutting and separating using a third LS to form third open grooves (20) for forming a plurality of second electrodes (39) and (39').

This second conductive film (5) consists of a metal and a transparent conductive oxide film (C
A multilayer film with TF) was used. The thickness of each is 300
~1500 people formed it.

As this CTF, a light-transmitting conductive film made of a non-oxide conductive film such as a chromium-silicon compound may be used.

These are electron beam evaporation method, sputtering method, photo C
A CVD method including a VD method and a photo-plasma CVD method was used to form the semiconductor layer at a temperature of 250° C. or lower in order to prevent deterioration of the semiconductor layer.

(as shown in FIG. 1(C)), a plurality of elements (
31) and (11) were connected in series at the connecting part (4).

FIG. 1(D) shows an attempt to further complete the present invention as a photoelectric conversion device. That is, as a passivation film, a silicon nitride film (21) is uniformly formed to a thickness of 500 to 2,000 layers by a plasma vapor phase method or a photo plasma vapor phase method, and the leakage current between each element is caused by adsorption of moisture, etc. This further prevented the outbreak.

FIG. 2 shows an energy band diagram in a longitudinal cross-sectional view taken along line AA' in FIG. 1(D). The drawing is irradiated with light (1
0) has a P-type semiconductor (6) on the surface side, and has an amorphous semiconductor (35-1) and a polycrystalline semiconductor (35-2).

Therefore, type I semiconductor is an amorphous semiconductor (7-1)
and a polycrystalline semiconductor (mer 2), and further constitutes an N-type semiconductor (8) behind it. Polycrystalline semiconductor (7
-2) had a thickness of 0.1 to 0.4μ and was effective in absorbing long wavelength light.

This N-type semiconductor may be formed into an amorphous or microcrystalline structure after photoannealing. This increases the number of steps. However, optical annealing can prevent local diffusion into the N-type semiconductor and I-type semiconductor, improving yield.

Furthermore, external lead-out terminals (24) and (24'') were provided at the periphery.

In this way, for the irradiation light (10), on the substrate (10 cm x 10 cm) as in this example, each element was
III 11 x 9211Im strip, and the width of the connection part is 150μm, and the width of the external extraction electrode part is 4.311II
11. With 4mm peripheral area, it is practically 88mm
Nine stages were provided within 92 mm.

As a result, the segment is 12.2% (1,05cm”)
When the conversion efficiency was 10.4%, the panel could have a conversion efficiency of 10.4% using 9 stages of series-connected resistors.

"Effects" The present invention performs laser annealing before or after forming an N- or P-type semiconductor layer, which is a step after forming a ■-type semiconductor, to improve the collection efficiency of long-wavelength light and, in turn, to improve the conversion efficiency. I let it happen. Furthermore, at this time, the connecting portion and the peripheral portion were allowed to maintain the same amorphous structure as in the initial stage, thereby making it possible to reduce the resistance caused by the crystallization of the semiconductor here and also to prevent the resulting increase in leakage current.

In addition, by polycrystalizing only the internal semiconductor on the side opposite to this incident light, it is possible to achieve a high current density there, but it is not easy to integrate, which is a feature of amorphous photoelectric conversion devices. (It was achieved without losing its characteristics.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the manufacturing process of the photoelectric conversion device of the present invention. FIG. 2 shows the energy band width corresponding to the longitudinal section taken along the line AA' of the present invention. 1...Transparent substrate 2...Transparent conductive film 3...Non-single crystal semiconductor 31.11...Photoelectric conversion element 4...Connection part 35- 1.35'-tor amorphous semiconductor 35-2.3
5'-2 Polycrystalline semiconductor 25... Excimer laser light 10... Irradiation light 6... P-type semiconductor 7-1... Amorphous I-type semiconductor 7-2.
... Polycrystalline I-type semiconductor 7 ... I-type semiconductor 8 ... N-type semiconductor 5 ... Back electrode conductor

Claims (1)

[Claims] 1. A first electrode on a substrate having an insulating surface, a non-single crystal semiconductor doped with hydrogen or a halogen element having a PIN junction in close contact with the electrode, and a non-single crystal semiconductor on the semiconductor. In a semiconductor device in which a plurality of photoelectric conversion elements having a second electrode and a second electrode are connected in series at a connecting part, crystallization of the semiconductor on the back side of the region constituting the photoelectric conversion element constitutes the connecting part. 1. A semiconductor device, characterized in that the semiconductor device is provided with a larger area than the semiconductor on the back side of the region. 2. In claim 1, the I-type semiconductor in the region constituting the photoelectric conversion element of a non-single-crystal semiconductor having a PIN junction containing hydrogen or a halogen element has a polycrystalline structure doped with hydrogen or a halogen element. A semiconductor characterized in that a low-resistance type semiconductor having a structure is provided on the back side opposite to the light irradiation surface, and an I-type semiconductor in a region constituting a connecting portion on the back side is made of a high-resistance type semiconductor having an amorphous structure. Device. 3. A semiconductor device according to claim 1, wherein the semiconductor on the surface side of the region constituting the photoelectric conversion element has an amorphous structure.