JPS63133579A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enhance the collecting efficiency of the long-wavelength light and, additionally, to enhance the transducing efficiency by a method wherein a laser annealing-process 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 electric-conductive film 2 is formed on the whole surface of a glass substrate 1; after that, a first opening 13 is formed by means of a laser processing-machine; first electrodes 15 are formed in device regions 31, 11. A non-monocrystalline semiconductor which generates the photovoltatic power by light illumination, i.e. a non-monocrystalline semiconductor layer 3 which contains a PIN junction, an NIP junction or a PI junction or an NI junction and is doped with hydrogen or a halogen element is formed on the assembly; during this process, the assembly is light-annealed by means of an excimer pulse-laser beam whose wavelength is less than 400 nm; thick regions 35-2, 35'-2, partially, on the side of away-from-the-surface electrode in an I-layer out of the non-monocrystalline 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 method for manufacturing a photoelectric conversion device capable of generating high voltage, in which a plurality of photoelectric conversion elements (also simply referred to as elements) are electrically connected in series.

"Prior Art" Conventionally, an amorphous semiconductor is known as a non-single crystal semiconductor to which hydrogen ξ or a halogen element is 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
In response to light irradiation with Ml, 5 (100 mW/cm''), the depletion layer became even shorter, resulting in deterioration.

"Problems to be Solved by the Present Invention" Active lubricants that generate electrons and holes upon irradiation with light are used for 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 a photoelectric conversion device having a PIN junction, the width of the depletion layer in the ■-type semiconductor is increased to 1μ or more, and the connection part for integration is made of an amorphous high-resistance 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 provides a method for applying pulsed intense light (with a pulse width of 10 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. ~1001 seconds)
By irradiating the I-type semiconductor layer or the ■-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 to 1.6 eV and 1.7 to 1 for amorphous semiconductors
, 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 nIIl or less, which has a relatively large light absorption coefficient of a semiconductor, was used as the light.

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

The present invention must not allow leakage at the periphery due to the simultaneous increase in electrical conductivity caused by the subsequent annealing. Therefore, in an integrated structure, isolation at the connecting portion must not be hindered. Therefore, in the present invention, 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 to the right of the first electrode 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 Figure 1 (^), a substrate with an insulating surface, such as a glass substrate (1), is shown (in the left-right direction in the drawing).
10 cm, medium LO 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') (500-50
00 people (typically 500 to 1500 people) were formed by sputtering or spraying.

After this, a YAG laser (wavelength 1.
06 μm (pulse width 80 ns) processing machine (manufactured by NEC Corporation)
An average output of 0.3 to 3- (focal length 40 mm) is applied, a laser beam with a diameter of 5IIIφ is focused, and a spot diameter of 20 to 70 μφ, typically 40 μφ is controlled by a microcomputer, and the laser beam is emitted from above. irradiate,
This scanning creates the first open groove (1) for the scribe line.
3) and laser scribe (referred to as LS) the first electrode (15) in each element region (31) and (11).
It was made by

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 irradiation is from the substrate side, so P-type (stxcl-X O < X < l) semiconductor (approximately 200 people) - I-type amorphous silicon semiconductor (
A non-single crystal semiconductor (3) having one PIN junction made of a semiconductor having approximately 1.5μ)-N type microcrystals (approximately 500) was formed with 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 an I-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 Figure 1 (^). The semiconductor before (after forming the PI junction, i.e., second representative example) or after forming the N-type semiconductor constituting the PIN junction (i.e., after forming the PIN junction, i.e., the first representative example) is subjected to the optical annealing process. used as a thing.

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. The irradiation part was moved as a scratch to optically anneal all the regions constituting the element.

Here, a Kestic excimer laser oscillator 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 (return 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.

In this way, it was possible to crystallize a region with a depth of 0.1 to 0.4 μm, which is 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~
Due to the short optical pulse annealing of 50 ns, during crystallization,
Almost no hydrogen or halogen elements already contained are vented to the outside. 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 3 μ compared to 0.3 μ in an amorphous PIN junction. It had the double feature of being able to be stretched. For this reason, the optimal thickness of one layer can be increased to 0.5 to 2.0 μm due to the composite structure with a crystalline semiconductor, compared to 0.5 μm when only amorphous semiconductor is used in a single layer. , short wavelength light is absorbed by the amorphous silicon semiconductor region (35-1) and (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 part (4) is a high-resistance type semiconductor, especially an amorphous half body, and the electrode (
39) and (39') to prevent leakage.

Furthermore, this laser annealing is applied to both ends of the device in the width direction (
It was placed 1 to 2 mm inward from the front and back ends of the drawing, and did not reach either end. As a result, regions (31) and (11) where amorphous semiconductors constitute elements
(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 opening (14) was formed by the second LSI process.

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

Thus, the second opening (14) is the 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, cutting and separation is performed by a third LS to form a third electrode for forming a plurality of second electrodes (39) and (39').
An open groove (20) was formed for isolation.

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 or sputtering method,
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 to prevent deterioration of the semiconductor layer.

Thus, 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, a silicon nitride film (21) is uniformly formed as a buffsivation film to a thickness of 500 to 2,000 layers by plasma vapor phase method or photo plasma vapor phase method to prevent leakage current between each element from occurring due to adsorption of moisture, etc. Prevented further.

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, an amorphous semiconductor (354), and a polycrystalline semiconductor (35-2).

Therefore, type I semiconductor is an amorphous semiconductor (7-1)
and a polycrystalline semiconductor (7-2), and further constitutes an N-type semiconductor (8) behind the polycrystalline semiconductor (7-2). 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 and L-type semiconductors, 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
It is provided on a strip of 101T1 x 92 mm, and the width of the connecting part is 150 μm, and the width of the external extraction electrode part is 4.3 mm.
Effectively 88mm x 92m with 4mm perimeter
There were nine stages within m.

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.

"Effect" The present invention performs laser annealing before or after forming an N- or P-type semiconductor layer, which is a step after forming an I-type semiconductor, to improve the integration 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 completely different from the ease of integration that has been a feature of amorphous photoelectric conversion devices. I was able to achieve this without losing that characteristic.

[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 ■-type semiconductor 7-2
...Polycrystalline ■-type semiconductor 7 ...I-type semiconductor 8 ...N-type semiconductor 5 ... Back electrode conductor

Claims (1)

[Claims] 1. A step of forming, on a substrate having an insulating surface, a first electrode and a non-single crystal semiconductor doped with hydrogen or a halogen element having a PIN junction in close contact with the electrode. A method for manufacturing a semiconductor device, comprising: irradiating the semiconductor with pulsed intense light from the back side opposite to the substrate to perform optical annealing; and forming a second electrode after the step. 2. Forming, on a substrate having an insulating surface, a first electrode and a non-single crystal semiconductor doped with hydrogen or a halogen element having a PI or NI junction in close contact with the electrode; A step of performing optical annealing by irradiating pulsed strong light from the back side opposite to the substrate, and
1. A method for manufacturing a semiconductor device, comprising a step of laminating and forming a type semiconductor, and a step of forming a second electrode after the step. 3. A method for manufacturing a semiconductor device according to claim 1 or 2, wherein the semiconductor is irradiated with an excimer laser having a wavelength of 400 nm or less in the optical annealing.