JPS5992519A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent a semiconductor device from contamination according to a different kind dopant by a method wherein a semiconductor layer is adhered previously on the inside face of a reaction vessel. CONSTITUTION:After a p-i-n junction type element is formed in a reaction vessel, when the wall of the vessel is etched by plasma using CF4, a thin film adhered on the wall can not be removed wholly, and because a part of the thin film is left as an etching remainder, it result in generation of a contaminating material when formation of a next p-i-n junction type element is to be formed. Because it is hard to remove completely the contaminating material according to etching, the element can be prevented from contamination by covering the upper part of the contaminating material with a semiconductor thin film not to apply a bad influence when the element is to be formed. When the p-i-n junction type element is to be formed, the wall of the vessel is covered with a p-type or an i-type semiconductor thin film according to the plasma CVD method, for example.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for manufacturing a multilayer semiconductor device, and particularly to a method for continuously forming a p-n or p-1-n junction multilayer device by a plasma CVD method. It relates to a manufacturing method suitable for.

[Prior art]

Generally, semiconductor devices using multilayer semiconductor thin films, such as A-8I PIN solar cells and line sensors, require the continuous formation of BP-type*XFI and N-type semiconductor thin films in the same container by plasma CVD. It is made by the manufacturer. At this time, when the pin type element was fabricated in the same container, element characteristics with good reproducibility could not be obtained. This is because contamination by the n-type dopant remains in the container after the pin-type element is formed, and is mixed into the p-layer when the pin-type element is formed next, which adversely affects the characteristics. Conventionally, in order to prevent the contamination of such n-type dopants, CF4 plasma etching was used to remove IJ-
The conventional method was to form a pin-type element into a J-type structure after processing. However, this cleaning method has a drawback in that it cannot completely remove n-type dopant contamination.

On the other hand, recently, peje has been proposed as a way to completely remove this pollution.
A method has been proposed in which each type of thin film is formed in a separate container. (Y, KuWano, 15thIE)
photovoltaic 5peci31ist
Conference) This method is effective in removing contamination from dopants, but requires a large amount of floor surface and dipping.
There were drawbacks such as a long conveyance system and a complicated mechanism.

[Purpose of the invention]

An object of the present invention is to continuously manufacture semiconductor devices made of multilayer semiconductor films without using a large number of containers.
An object of the present invention is to provide a method for manufacturing a semiconductor device that can prevent contamination due to different types of dopants.

[Summary of the invention]

To achieve the above object, the present invention eliminates contamination by coating the container wall with a contamination-free semiconductor thin film rather than by etching the container wall. .

When plasma etching the wall of the container using CF4 after forming the pin type element, it is not possible to remove all of the thin film adhered to the wall, and some etching residue remains in the part far from the electrode. occurs.

In other words, the discharge conditions differ between deposition and etching.
It seems that there will be some etching residue. It is thought that this etching residue will become a contaminating cut during the next formation of a pin type element. Therefore, it is considered extremely difficult to completely remove contaminants by etching, so it is possible to prevent contamination by covering the contaminants with a semiconductor thin film that does not have a negative effect on device formation. Become.

For example, in the case of a pin type element, the container wall was coated with a p-type or i-type semiconductor thin film by plasma CVD. In this way, the contamination of the container wall soil could be completely covered with a semiconductor thin film that is harmless to the device characteristics, thereby eliminating the adverse effects of the contaminants.

[Embodiments of the invention]

Hereinafter, a tenth embodiment of the F1 invention will be described.

Example 1 According to the block diagram shown in FIG. 1, a semi-four-piece device having the cross-sectional structure shown in FIG. 2 was formed. That is, first, the inner wall surface of a reaction vessel in which a semiconductor thin film was to be formed was coated with a pm semiconductor thin film. For this purpose, 10% monosilane diluted with hydrogen and 5001 pl diporane diluted with hydrogen were introduced into the reactor at a ratio of monosilane/diborane=110.01, and a p-type amorphous Si thin film was formed by plasma CVD. Although the coating thickness on the wall surface is not clear, it is 500 mm at the substrate location.
The coating was applied to a thickness of 0.

Next, in order to tabulate a semiconductor device having the cross-sectional structure shown in FIG. 2, a glass substrate 1 having a transparent conductive film 2 was introduced into a reaction vessel, and an amorphous S1 thin film was formed. Transparent conductive film 2
, 8nOx) formed by electron beam evaporation. The p-type thin film 3, the n-type thin film 4, and the n-type thin film 5 were sequentially and continuously formed according to the following specifications. The p-type thin film 3 is diluted with hydrogen.
Using 0% monosilane and 5001 pl diborane diluted with hydrogen at a ratio of monosilane/diborane = 110.01,
By plasma CVD method! It was formed to a film thickness of 7,100 people. The 1-layer thin film 4 was formed using monosilane diluted with 10% hydrogen to a film thickness of fi5,000 by plasma CVD.

The n-type thin film 5 consists of monosilane diluted with 10% hydrogen and phosphine diluted with hydrogen 500p, monosilane/phosphine=1.
10.01, and the plasma CVD method
It was formed to a film thickness of 100 mm.

The substrate 1 on which the amorphous 81 layer 3,4°5 was formed by the above process was taken out from the reaction vessel, and an electrode 6 was formed to a thickness of J55000A by resistive heating vapor deposition of At using a metal mask.

Table 1 shows the results of measuring the photovoltaic characteristics of the semiconductor device formed through the above steps. Furthermore, the first
For comparison, the table also shows the characteristics when the conventional manufacturing method, plasma etching with CF4, was used for schiff cleaning. The results shown are the results of forming each layer twice to confirm reproducibility.

The present invention is superior to the conventional method in all of the open circuit voltage, short circuit current 1 fill factor, and conversion efficiency. Furthermore, it is clear that the reproducibility of characteristics is also superior.

Next, a second embodiment of the present invention will be shown below.

Embodiment 2 In a second embodiment of the present invention, in addition to the manufacturing process shown in FIG. 1, a step of etching the container wall with CF4 plasma is added as a first step to produce the semiconductor device shown in FIG. was formed. First, the inside of the reaction vessel was subjected to CPa plasma etching without placing the glass substrate inside the reaction vessel. At this time, the two 11 poles were completely cleaned, but
The amorphous Si deposited up to that point remained in some areas on the wall of the container. Next, 10% monosilane diluted with hydrogen was subjected to a plasma CVD reaction in the container to coat the container wall with type 1 amorphous Si. Thereafter, a glass substrate l having a transparent conductive film 2 was introduced into the container, and p-type, i-type, and n-type amorphous Si were formed in exactly the same manner as in Example 1.

Next, the sample was taken out from the container, and At was deposited using a metal mask to produce a semiconductor device having the structure shown in FIG. 2.

Table 2 shows the results of measuring the photovoltaic characteristics of the semiconductor device formed through the above steps. Also, the second
For comparison, the table also shows the photovoltaic power characteristics of a semiconductor device formed by coating the container wall with n-type amorphous Si instead of i-type and intentionally contaminating the container wall. For coating the n-type layer, 10% monosilane diluted with hydrogen and 500P diluted with hydrogen were used.
Phosphine, monosilane/phosphine = 110.01
It was deposited by plasma CVD method. In addition,
In order to confirm reproducibility, the results of forming each layer twice are shown.

For all characteristics, Example 2 is close to Example 1,
Results with good reproducibility were obtained. On the other hand, in the comparative example, the characteristics were very poor, and it was confirmed that the semiconductor device characteristics were very poor due to contamination of the container wall.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to prevent the influence of contamination on the wall surface of a reaction vessel, and it is possible to obtain a semiconductor device with excellent characteristics.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing a cross-sectional structure of a semiconductor device formed according to the present invention. l...Glass substrate, 2...Transparent conductive film, 3...p
Type thin film, Figure 1

Claims (1)

[Claims] A method of laminating and depositing a plurality of semiconductor layers in a reaction vessel, characterized in that a semiconductor layer of the i-type or the same conductivity type as the first layer is deposited on the inner surface of the reaction vessel in advance. Method of manufacturing the device.