JPS60180142A - Manufacture of semiconductor thin film - Google Patents

Abstract

PURPOSE:To simplify the process and suppress generation of auto-doping of impurity to amorphous silicon film by forming a thin amorphous silicon film by the vacuum deposition method on a single crystal insulated substrate and causing a single crystal silicon film to epitaxially grow thereon by the ionized vacuum deposition method. CONSTITUTION:A thin amorphous silicon film 2 is formed by the ionized vacuum deposition through the steps that a single crystal sapphier substrate 1 is arranged within a vacuum chamber of the ionized vacuum deposition apparatus, temperature of substrate 1 is held at a room temperature, silicon which is the vaporization source is vaporized by irradiation of electron beam, a part of vapor of silicon is ionized by collision with hot electrons, the ionized silicon atoms are accelerated by applying an acceleration voltage and the silicon atoms are vacuum deposited on the substrate 1. While keeping a degree of vacuum, temperature of substrate 1 is heated up to 800 deg.C and is held and a single crystal silicon film by the ionized vacuum deposition method is caused to epitaxially grow by vacuum depositing the silicon atoms 3 of the amorphous silicon film 2. In this case, the amorphous silicon film 2 is single-crystallized and a single crystal silicon film 4 is formed by the epitaxial growth method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The invention relates to a method for manufacturing a semiconductor thin film by epitaxially forming a single crystal silicon film on a single crystal substrate such as a single crystal sapphire substrate.

[Prior art]

In general, SOS (silicon o
The nsapphire) method is well known, and this is a method to evixically grow a single crystal silicon film on a single crystal sapphire substrate, which is a single crystal insulating substrate. A monocrystalline silicon film is epitaxially grown on a heated sapphire substrate using a mixed gas of SiH4 and H2 to produce an SOS film, which is a semiconductor thin film.

However, in the conventional method described above, since the SOS film is manufactured at a high temperature of 950C, the silicon does not grow to a planar K-9 shape on the sapphire substrate, and the sapphire and silicon react in places and generate nuclei. , 3 in various directions
There is a drawback that dimensional silicon crystallization occurs, leading to an increase in defect density in the SOS film and a decrease in rear mobility.

Here, the 131st Committee on Thin Films, Japan Society for the Promotion of Science, Psuma. Ion Processing Subcommittee Joint Study Group Fee P. 16-19
(December 18, 1981) and lpanese J.
Internal of Applied Physics
Vol1. 22 No. 7, July, 1
983 pp. As described in L 438 to 440 K, Makoto Ishida of the Department of Electrical and Electronic Engineering, Toyohashi University of Technology and five others have reported a method for producing an SOS film that eliminates the above-mentioned drawbacks.

In the first step, a buffer layer with a thickness of 20 to 200 A is deposited on a sapphire substrate whose main surface is (1102) mirror-polished by chemical and mechanical etching at room temperature. An amorphous silicon film is formed, and then in a second step, CvD
From the knowledge of the equipment, K:SiH on the amorphous silicon film
950-101 single crystal silicon film by thermal decomposition method of 4
A single crystal silicon film is grown epitaxially at a temperature of 0 C, and a single crystal silicon film is grown epitaxially on the sapphire substrate through both of the steps described above to produce an SOS film.

However, this method has two drawbacks. First, the IK
1. In order to form a thin and uniform amorphous silicon film on a sapphire substrate, it is necessary to apply an energy of several tens to several hundreds of eV to the silicon to cause silicon atoms to rush into the sapphire substrate. Since energy of 10 to several 100 eV is not applied, as mentioned above, two devices are required: a sputter ring device for the amorphous thin film and a CVD device for heat q of SiH4, making the process complicated. There is.

When transferring the sapphire substrate on which the amorphous silicon film was formed by the 2nd K1 sputtering device to the CVD device, the amorphous silicon film was exposed to the outside air. If the amorphous silicon film is oxidized or contaminated by adhesion of contaminants such as carbon, the amorphous silicon film may be heated to 1000 C before epitaxial growth of the monocrystalline silicon film.
, it is necessary to perform a high-temperature pre-cleaning process for 5 minutes to remove contaminants on the amorphous silicon film, which is very time-consuming, and furthermore, the pre-cleaning process alone is not enough to remove the oxides from the amorphous silicon film F. If aluminum cannot be removed and a pre-cleaning treatment is performed at a high temperature of 1000 C, autodoping of aluminum from the sapphire substrate to the amorphous silicon film tends to occur.

Purpose of the Invention The invention was developed with the above-mentioned points in mind, and it is possible to form a thin film of a conventional conductor using one device, and to eliminate the need for the thin film to be exposed to the outside air during formation. The purpose of this invention is to prevent contamination of the 111I amorphous silicon film, eliminate the conventional i cleaning process, simplify the process, and suppress the autopumping of impurities into the 111I amorphous silicon film.

[Structure of the invention]

The present invention provides manufacturing of a semiconductor thin film characterized by comprising the steps of: forming a thin amorphous silicon film on a single crystal insulating substrate by vapor deposition; and evictifying the single crystal silicon film on the amorphous silicon valve membrane using an ionization method. It's a method.

〔Effect of the invention〕

Therefore, according to the method of manufacturing a semiconductor thin film of the present invention, an amorphous silicon film is formed by a vapor deposition method, and a single crystal silicon film is evixtally grown by an ionization vapor deposition method.
This makes it possible to form amorphous silicon films and single-crystal silicon films, eliminates exposure of semiconductor thin films to the outside air during formation, and prevents contamination of the thin films. can.

Furthermore, it is possible to suppress the need to perform a conventional pre-cleaning treatment during the formation of a semiconductor thin film, and to prevent doping of impurities into the amorphous silicon film due to high-temperature processing.

1 Embodiment] Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

First, as shown in Figure 1, a single-crystal sapphire substrate (1) whose main surface is (1102), which has been mirror-polished by chemical and mechanical etching, is placed in a vacuum chamber of an ionization vapor deposition apparatus maintained at a vacuum level of I x 10 Torr. and the board (1
) was maintained at room temperature, and silicon, which was an evaporation source, was evaporated by irradiation with an electron beam from the electron beam source of the device, and a portion of the silicon vapor was ionized by collision with thermionic electrons. Silicon Kyoko K5KV
An acceleration voltage of several 10 eVi to several 10 eVi is applied on average.
Energy of 0eV is applied to silicon atoms to accelerate them, and as shown in Figure 2, the silicon atoms are attached to the substrate (
1) to form a thin amorphous silicon film (2) with a thickness of 40A on the substrate (1) by ionization vapor deposition.

Next, while maintaining the above-mentioned degree of vacuum, the substrate is heated to (1) degree and held at 8000 degrees, and an amorphous silicon film (2 ) on top of the silicon coating (3), and then epitaxially grow a crystalline silicon film using ionization deposition method 1.

-, by forming the amorphous silicon film while maintaining the temperature of the substrate (1) at 800 CK, the amorphous silicon film (2) becomes a single crystal, and as shown in FIG. A monocrystalline silicon film with a thickness of 11 lm/4) is formed by crystallization, and S is a semiconductor thin film.
The OS film (5) has been manufactured.

Therefore, according to the embodiment, the amorphous silicon film (2) and the single crystal silicon film can be formed using one ionization vapor deposition system 1iJK, and the SOS film (5)
It is possible to prevent the amorphous silicon film (2) from being exposed to the outside air during the formation, thereby preventing contamination of the amorphous silicon film (2), etc., thereby simplifying the process.

Furthermore, during the formation of the SOS film (5), it is necessary to perform a high-temperature pre-cleaning process as in the past. It is possible to suppress the occurrence of autodoping such as, etc., significantly reduce the defect density in the single silicon film (4) compared to the conventional SOS film, and improve the single-layer mobility.

Note that the amorphous silicon film (2) may be formed by a normal vapor deposition method other than ionization vaporization.

Furthermore, the present invention can be implemented in the same manner even if a single crystal spinane film is used instead of the sapphire substrate (1).

4441 Brief Description of the Drawings The drawings show one embodiment of the method of manufacturing a semiconductor thin film of the present invention, and FIGS. 1 to 4 are sectional views showing the manufacturing steps, respectively.

(1)... Sapphire substrate, (2)... Amorphous silicon film, 1.4)... Single crystal silicon film, (5
)...SOS film.

Claims (1)

[Claims] ■ A step of forming a thin amorphous silicon film by vapor deposition on a single crystal insulating substrate; 17. A method for producing a semiconductor thin film, comprising the step of epitaxially growing a silicon film on the 17th silicon film by ionization vapor deposition.