JPH05144745A - Manufacture of semiconductor substrate - Google Patents

Abstract

PURPOSE:To provide the manufacturing method, of a semiconductor substrate, wherein a film thickness can be controlled easily, an arbitrary film thickness can be obtained and a high semiconductor characteristic can be obtained. CONSTITUTION:A film formation substrate 1 whose influence of a silicon semiconductor film 2 is small and which is composed mainly of a low-melting-point metal whose melting point is lower than that of the film is used. A plasma flame-sprayed silicon semiconductor film 2 in an arbitrary film thickness is formed on the film-formation substrate 1; after that, the film-formation substrate 1 is heated and its temperature is raised up to the melting point of its constituent metal; the film-formation substrate 1 is melted; the plasma flame-sprayed silicon semiconductor film 2 is separated; after that, the low-melting-point metal which has adhered to and is left on the separation face of the plasma flame- sprayed silicon semiconductor film 2 is removed by a proper etching operation; a silicon semiconductor substrate 11 is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor substrate, particularly a polycrystalline silicon substrate.

[0002]

2. Description of the Related Art Conventionally, a cast polycrystalline silicon substrate has been used as a polycrystalline silicon substrate, but this cast polycrystalline silicon substrate is subjected to a heat treatment process at a high temperature exceeding 1000 ° C. in a substrate forming process. However, the manufacturing process is complicated and difficult, and the substrate itself is expensive.

Therefore, a method of manufacturing a polycrystalline silicon substrate by a plasma spraying method using a powder of a silicon semiconductor material has been considered. As a concrete method of manufacturing this polycrystalline silicon substrate, a very thick silicon semiconductor sprayed film having a film thickness of 100 μm or more is formed on a film forming substrate such as a stainless substrate, and then the film is spontaneously peeled off. there were.

[0004]

However, in such a manufacturing method, the desired effect cannot be obtained unless the thickness of the polycrystalline silicon substrate is considerably increased, and the thickness of the polycrystalline silicon substrate can be controlled. It is extremely difficult to obtain a polycrystalline silicon substrate having a thin film thickness by using this method.

Further, in this manufacturing method, since a stainless steel substrate or the like is used as the film forming substrate, impurities that adversely affect the silicon semiconductor sprayed film are taken into the polycrystalline silicon substrate from the film forming substrate when the semiconductor sprayed film is formed. As a result, the characteristics of the photoelectric conversion device using this polycrystalline silicon substrate are deteriorated.

The present invention has been made in view of the above conventional problems, and it is a semiconductor substrate in which the film thickness can be easily controlled, an arbitrary film thickness can be obtained, and high semiconductor characteristics can be obtained. The purpose is to provide a manufacturing method.

[0007]

A method of manufacturing a semiconductor according to the present invention has a low influence on the characteristics of a semiconductor substrate to be formed and has a melting point lower than that of the semiconductor substrate, for example, tin, A film forming substrate mainly composed of a low melting point metal selected from lead, indium, gallium, and aluminum is used, and a semiconductor is formed on the film forming substrate by a plasma spraying method using the material powder of the semiconductor substrate as a raw material. It is characterized in that a film is formed, and thereafter, the film-forming substrate is heated to the melting point of the constituent metal and heated to be melted and removed.

[0008]

After the plasma sprayed semiconductor thin film is formed on the film-forming substrate mainly composed of the low melting point metal, the temperature is raised to the melting point of the constituent metal of the film-forming substrate to melt the film-forming substrate. The plasma sprayed semiconductor thin film is separated, and then the low melting point metal remaining on the separation surface of the plasma sprayed semiconductor thin film is removed by appropriate etching to obtain a semiconductor substrate. According to such a manufacturing method, the thickness of the plasma sprayed semiconductor film can be freely controlled, and a thin film semiconductor substrate having an arbitrary thickness can be obtained.

Further, the low melting point metal, which is the main constituent of the film forming substrate, has a smaller diffusion coefficient than iron, which is the main constituent of stainless steel, and this low melting point metal is contained in the plasma sprayed semiconductor thin film formed on the film forming substrate. Difficult to affect the negative effect.

Further, by selecting, as the main metal of the film forming substrate, a low melting point metal that has little influence on the semiconductor characteristics of the semiconductor material, it is possible to prevent deterioration of the semiconductor characteristics.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a manufacturing process of a semiconductor substrate which is one embodiment according to the present invention, and specifically shows a manufacturing process of a polycrystalline silicon substrate.

Film-forming substrate 1 used in this manufacturing process
Is mainly composed of a low melting point metal having a lower melting point than that of the semiconductor substrate 11, that is, tin (S
n), lead (Pb), indium (In), gallium (G
A low melting point metal selected from a) and aluminum (Al) is preferred. In this embodiment, the film forming substrate 1 is mainly made of tin.

Next, a method of manufacturing a polycrystalline silicon substrate 11 using this film forming substrate 1 will be described with reference to FIGS.
It will be specifically described with reference to.

First, a polycrystalline silicon semiconductor film 2 is formed on a film forming substrate 1 by a plasma spraying method using silicon powder as a raw material (see FIG. 1 (a)). The plasma spraying conditions in this case are as shown in Table 1.

[0015]

[Table 1]

Next, the film forming substrate 1 on which the polycrystalline silicon semiconductor film 2 is formed is placed on the heating plate 3 and is placed in a nitrogen (N ₂ ) atmosphere, and the heating plate 3 is placed.
Thus, the film-forming substrate 1 is heated to the melting point (250 ° C.) of the constituent metal, tin, to be melted (see FIG. 1 (b)).

When the surface portion of the film forming substrate 1 is melted, the polycrystalline silicon semiconductor film 2 is peeled off from the film forming substrate 1 to separate and remove the film forming substrate 1 (see FIG. 1 (c)). ..

Finally, the tin remaining on the back surface of the polycrystalline silicon semiconductor film 2, that is, the separation surface 2a, is removed from hydrochloric acid (HC
l) Etching off with a solution or the like to obtain a finished polycrystalline silicon substrate.

Next, FIG. 2 shows the structure of a photoelectric conversion device using the polycrystalline silicon substrate manufactured through the above steps.

In the figure, 11 is n-type polycrystalline silicon made of a polycrystalline silicon substrate manufactured by the plasma spraying method described above, 12 is intrinsic (i-type) amorphous silicon,
13 is p-type amorphous silicon, 14 is ITO (Indium Tin)
The transparent conductive film made of oxide (Oxide), and 15 are back electrodes made of aluminum which are in contact with the n-type polycrystalline silicon 11.

As a method of manufacturing this photoelectric conversion device, first, plasma gas CVD is performed on the n-type polycrystalline silicon 11.
The i-type amorphous silicon 12 is formed by the method. Next, p-type amorphous silicon 13 is formed on the i-type amorphous silicon 12 by the plasma gas CVD method.

Subsequently, the p-type amorphous silicon 13 is formed.
A transparent conductive film 14 is formed thereon as a window-side electrode, and finally, a back surface electrode 15 is formed on the other main surface of the n-type polycrystalline silicon 11.
Are formed to complete the photoelectric conversion device.

Thus, it has been confirmed that the photoelectric conversion device having the above structure has good photoelectric conversion characteristics.

[0024]

As described above in detail, according to the present invention, a film-forming substrate mainly composed of a low melting point metal having a small influence on the characteristics of the semiconductor to be formed and having a melting point lower than that of the semiconductor is formed. To form a plasma sprayed semiconductor film,
After that, by heating up to the melting point of the metal of the film forming substrate to melt the film forming substrate and separating the plasma sprayed semiconductor film, a semiconductor substrate can be obtained without a high temperature process and semiconductor cutting processing. it can.

In this case, the film thickness of the plasma sprayed semiconductor film can be easily controlled, an arbitrary film thickness can be obtained, and the material cost and the manufacturing cost can be reduced, and moreover, it is a main component of the film forming substrate. The melting point metal hardly diffuses into the plasma sprayed semiconductor film and exerts no adverse effect, and high semiconductor characteristics can be secured.

Further, when a polycrystalline semiconductor substrate such as a plasma sprayed silicon semiconductor substrate is applied to a photoelectric conversion device, a film thickness of 100 μm or less is desirable, but according to the manufacturing method, a semiconductor having a desired thin film thickness is obtained. A substrate can be easily obtained, and a photoelectric conversion device having good photoelectric conversion characteristics can be obtained.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram for explaining a method for manufacturing a polycrystalline silicon substrate which is an embodiment according to the present invention.

FIG. 2 is a sectional view of a photoelectric conversion device using the same polycrystalline silicon substrate.

[Explanation of symbols]

 1 Tin Substrate (Film Forming Substrate) 2 Polycrystalline Silicon Substrate 2a Back Side (Separation Surface) of Polycrystalline Silicon Substrate 3 Heating Plate 11 n-type Polycrystalline Silicon Substrate 12 i-type Amorphous Silicon 13 p-type Amorphous Silicon 14 Transparent Conductive film 15 Backside electrode

Claims (1)

[Claims] 1. A raw material of a material powder of a semiconductor substrate is formed on a film-forming substrate mainly composed of a low melting point metal having a low melting point lower than that of the semiconductor substrate and having little influence on the characteristics of the semiconductor substrate to be formed. As a method for manufacturing a semiconductor substrate, a semiconductor film is formed by a plasma spraying method, the film forming substrate is heated to the melting point of the constituent metal and heated to be melted and removed.