JPS6236807A - Manufacture of single-crystal thin film - Google Patents

Abstract

PURPOSE:To obtain a large area single-crystal film with superior quality by reducing the splashing of polycrystalline or amorphous silicon of the SOI section with the scanning direction of an energy beam and the form of pattern of the SOI. CONSTITUTION:The heat source or sample is scanned so that the scanning direction of the energy source will be formed with inclination of more than 10 deg. and less than 90 deg. or more than -10 deg. and less than -90 deg. from the vertical direction with respect to the boundary between the polycrystalline silicon (amorphous silicon) on the exposed surface of a substrate and the insulation film, thereby preventing the splashing of a polycrystalline film that can be easily produced near the boundary between the SIO section and the seed section. Thus, growth of crystal is facilitated to allow the formation of a large area single crystal growth region.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for manufacturing a single crystal thin film, and in particular to a method for producing a single crystal thin film, in particular a method of irradiating an amorphous thin film on an insulating film deposited on the surface of a semiconductor substrate with an energy beam such as a laser beam. This invention relates to a method for producing high quality single crystal thin films.

[Background of the invention]

Conventionally, for the formation of single crystal thin films, Japanese Patent Application Laid-Open No. 56-73607
In bridging epitaxy using seeds for crystal growth as described in the above issue, no consideration was given to the scanning direction of the heat source and the shape of the SOI pattern. Therefore, polycrystalline silicon was likely to scatter near the boundary between the 801 part and the seed part due to sudden thermal changes.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems in manufacturing a single crystal film on an insulating film and to provide a method for obtaining a high-quality, large-area single crystal film.

[Summary of the invention]

In order to achieve the above object, the present invention has developed a method to solve the problem of polycrystalline or amorphous silicon that is generated due to the difference in thermal conductivity between the single crystal silicon substrate and the insulating film that exist under the polycrystalline or amorphous silicon in the SOI part and the seed part. SOI caused by differences in film melting
The scattering of polycrystalline or amorphous silicon in the area is reduced by changing the scanning direction of the energy beam and the pattern shape of the SOI.

[Embodiments of the invention]

The present invention will be explained in detail below. First, an oxide film 2 having a thickness of 0.4 μm was formed on a portion of a single crystal silicon (100) substrate 1 by a well-known l,0CO3 oxidation method. After this,
A polycrystalline silicon film 3 having a thickness of 3) 0.35 μm was formed by thermal decomposition of SiH4.

This sample is shown in FIG. Thereafter, continuous wave argon ion laser light 4 was irradiated while scanning 5 as shown in the figure, thereby converting the polycrystalline silicon film 3 into a single crystal. The irradiation conditions were a sample substrate temperature of 500°C and a beam diameter of 100 μm.
, irradiation power 5-15W, beam scanning speed 1-100
rs/s. By this irradiation, the entire polycrystalline silicon film 3 and the surface portion of the single crystal silicon substrate 1 are melted, and in the reassimilation process, the single crystal grows from the surface (seed part) of the single crystal silicon substrate 1 to the surface of the oxide film 2. Area (SOI
The region on the oxide film 2 is made into a single crystal. At this time, the power required to melt the polycrystalline silicon film in the seed part and the SOI part is 6W and 7W, and a laser power of 7W or more is required to monocrystallize the polycrystalline silicon film 3 on the insulating film 2. It is. Then 9W, 1 cs
SOI with different pattern shapes were irradiated under laser conditions of /s.

i) Laser scanning direction and seed angle When the seed 6/5OI7 boundary is perpendicular to the laser scanning direction, the inclination angle of the seed is 0 degrees, and the inclination angle of the seed in the counterclockwise direction is expressed as ■θ. This is shown in FIG. This sample was irradiated with laser light while scanning, and crystal growth from the seed portion of 801 parts was examined. As a result, O is 110~
At +10 degrees, the polycrystalline silicon film in the SOI part was scattered, and at other seed inclination angles O, SOI crystal growth layers were obtained. In addition, when the seed inclination angle θ is around 1180 degrees, where the laser beam scans from the SOI part to the seed part, the reassimilation from the seed part occurs before the polycrystalline silicon on the SOI, so it is 2 to 3 μm. A single crystal film with good properties was obtained. It can be fully utilized by considering the device structure.

jt) Angle of SOI pattern FIG. 3 shows laser irradiation when the angle α of the SOI pattern is changed. When the angle of the SOI pattern with respect to the laser scanning direction was less than 100 degrees, the polycrystalline silicon film was scattered at the SOI pattern angle. At a pattern angle α larger than that, an SOI crystal growth layer was formed.

jii) Angle between linear beam and seed In the case of a linear beam, the angle of the seed 6/5OI7 boundary with respect to the inclination angle β of the linear beam is set as the inclination angle γ of the seed. This is shown in FIG.

As a result of irradiating the laser beam while scanning and examining the crystal growth from the seed part of the SOI part, when γ is -10 to +10,
The polycrystalline silicon film in the SOI portion was scattered, and SOI crystal growth layers were obtained at other seed inclination angles γ. This result was similarly obtained even when the inclination angle β of the linear beam was changed.

Although a continuous wave argon-in-Olaser beam was used in this embodiment, the effects of the present invention are not limited to this, and local heating with an electron beam, a strip heater, etc. may be used, and an oxide film can also be used as long as it is an insulating film. A similar effect can be obtained.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, scattering of the polycrystalline silicon film that tends to occur near the boundary between the SOI part and the seed part can be prevented, and the crystal acid length can be easily increased, so that large-area single crystal growth can be achieved. It becomes possible to form a region.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the sample, and FIGS. 2 to 4 are diagrams showing the surface of the sample. ]... Single crystal silicon substrate, 2... Oxide film, 3...
・Polycrystalline silicon film, 4...Laser light, 5...Laser scanning direction, 6...Seed, 7...S○ process, 0...
・Inclination angle of the seed with respect to the laser scanning direction, α...
The angle of the SOI pattern, β...the angle with respect to the beam scanning direction of the linear beam, and γ...the inclination angle of the seed with respect to the angle of the linear beam.

Claims (1)

[Claims] 1. A polycrystalline or amorphous silicon thin film that continuously covers the exposed surface of the semiconductor substrate and the insulating film deposited on the semiconductor substrate is exposed to beam energy such as a laser beam or an electron beam. In the method of single crystallization by irradiation with irradiation or local heating melting using a linear heater, the energy and the scanning direction of the source are different from those of the polycrystalline silicon (amorphous silicon) on the exposed substrate surface and the insulating film. 10° or more and less than 90° perpendicular to the boundary, or -1
1. A method for producing a single crystal thin film, comprising scanning a heat source or a sample at an angle of 0° or more and less than -90°. 2. When the solid-liquid interface is linear or elliptical as in the above-mentioned linear heater, the boundary between the polycrystalline silicon (amorphous silicon) and the insulating film on the substrate surface where the long side of the solid-liquid interface is exposed A method for manufacturing a single crystal thin film according to claim 1, characterized in that the heat source or the sample is scanned so as to advance at an inclination of 10 degrees or more with respect to a direction coincident with the direction. 3. The above energy source is polycrystalline silicon (
2. The method of manufacturing a single crystal thin film according to claim 1, wherein the angle of the pattern of the insulating film when transferred from the amorphous silicon onto the insulating film is an angle of 100° or more.