JPH046823A - Manufacture of crystalline semiconductor thin film - Google Patents

Abstract

PURPOSE:To obtain a semiconductor thin film whose defect density is low, which is provided with a controllable position and which contains crystals of a large particle size by a method wherein a shielding film provided with an insulating film and with a groove region is laminated on an amorphous semiconductor film, the amorphous semiconductor film is changed into a fine-crystal semiconductor film by a laser beam impinging from the groove region and the fine-crystal semiconductor film is changed into a polycrystalline semiconductor film by a heat treatment. CONSTITUTION:An amorphous semiconductor film which has been formed on an insulating substrate is crystallized to obtain a polycrystalline semiconductor film; thereby, a crystalline semiconductor thin film is manufactured. In this case, an amorphous semiconductor film 2 is formed on an insulating substrate 1; after that, a shielding film 4 which is provided with an insulating film 3 and with groove regions 8 is laminated. Then, the amorphous semiconductor film 2 is changed into a fine-crystal semiconductor film 6 by a laser beam 5 impinging from the groove regions 8 in the shielding film 4; the fine-crystal semiconductor film 6 is changed into a polycrystalline semiconductor film 9 by a heat treatment at 500 deg.C or higher. For example, a laser beam 5 which has reached an amorphous Si film 2 through groove regions 8 melts the silicon film locally; the amorphous Si film 2 is changed into a fine-crystal Si film 6 including fine-crystal regions 7. The fine-crystal regions 7 act as crystal growth nuclei at a later process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a crystalline semiconductor thin film, and the present invention relates to a method for manufacturing a crystalline semiconductor thin film.
It is most suitable for use in forming a lator structure.

[Conventional technology]

As a conventional example of a method for manufacturing a crystalline semiconductor thin film, JP-A-61
There is one described in JP-288413. FIG. 2(a) to FIG. 2(c) are sectional views showing a conventional example in the order of steps. The following will explain based on the drawings.

First, as shown in FIG. 2(a), a polycrystalline Si film (polycrystalline silicon film) 9 is formed on a quartz substrate 10 by low pressure vapor phase epitaxy, and then a 5in2 film is formed as shown in FIG. 2(b). film(
A silicon dioxide film) 11 is laminated. Next, a laser beam 5 is irradiated to melt and crystallize the polycrystalline Si film 9 to form a single crystal Si film (single crystal silicon film) 12 as shown in FIG. 2(C). The 5in2 film 11 suppresses the flow of silicon caused by the melting of the polycrystalline Si film 9 during laser irradiation, and the surface of the single crystal Si film 12 solidified after cooling is made of Si.
The surface is flatter than when the O2 film 11 is not present.

[Problem to be solved by the invention]

However, when the silicon film melts and solidifies after irradiating the polycrystalline Si film 9 with the laser beam 5, crystal nuclei are generated in the silicon film from completely arbitrary and uncontrolled positions, and the resulting crystal As shown in FIG. 3, a polycrystalline film 13 having crystal grain boundaries at uncontrollable positions is formed. As a result, the film quality becomes non-uniform. In addition, in order to obtain a film having large crystal grains, the thickness of the polycrystalline Si film 9 is made sufficiently thick so that adjacent crystal grains mutually hinder the growth of neighboring crystal grains. There was a need. Therefore, there is a problem that the obtained crystalline semiconductor thin film tends to have a high defect density.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for manufacturing a crystalline semiconductor thin film containing large grain size crystals with a low defect density and controllable positions.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the method for manufacturing a crystalline semiconductor thin film according to the present invention is a method for manufacturing a polycrystalline semiconductor thin film by crystallizing an amorphous semiconductor film formed on an insulating substrate. In the method for producing a crystalline semiconductor thin film to obtain a semiconductor film, after forming the amorphous semiconductor film on the insulating substrate, the step of laminating an insulating film and a shielding film having a groove region; A step of changing the amorphous semiconductor film into a microcrystalline semiconductor film by a laser beam incident from a groove region of the film, and a step of changing the microcrystalline semiconductor film into a polycrystalline semiconductor film by heat treatment at 500° C. or higher. It is characterized by

〔Example〕

The method for manufacturing a crystalline semiconductor thin film according to the present invention will be described below.
An example applied to the formation of a structure will be described with reference to the drawings.

First, as shown in FIG. 1(a), an amorphous Si film 2 is formed on an insulating substrate 1, and then an insulating film 3 and a shielding film 4 are laminated as shown in FIG. 1(b). Furthermore, after forming groove regions 8 in the shielding film 4 by photolithography, laser beam 5 is irradiated to form amorphous 5iIII2 into a microcrystalline Si film including microcrystalline regions 7, as shown in FIG. 1(C). Convert to 6.

The shielding film 4 protects the laser beam 5 during irradiation with the laser beam 5.
The laser beam 5 that does not pass through the groove region 8 and reaches the amorphous Si film 2 locally melts the silicon film.

The molten silicon film is fluid and eventually radiates heat and cools and solidifies, but because of the insulating film 3, the microcrystalline Si film 6
The flatness is good.

The microcrystalline region 7 formed by the laser beam 7 becomes a crystal growth nucleus in a later step. After removing the shielding film 4 as shown in FIG. 1(d), the shielding film 4 is removed as shown in FIG. 1(e).
By heat treatment at 00° C. or higher, crystal growth is performed using the microcrystalline regions 7 as crystal growth nuclei, and a polycrystalline Si film 9 is obtained. In this way, by enlarging the grain size of the crystal grains through lateral crystal growth, it is possible to increase the thickness of the silicon film by 600 mm without increasing the thickness of the silicon film.
A polycrystalline Si film 9 having large crystal grains can be obtained even with a thin film having a thickness of 1 angstrom or less and 250 angstroms or more.

〔Effect of the invention〕

The method for manufacturing a crystalline semiconductor thin film of the present invention has the advantage that a flat crystalline semiconductor thin film having a thickness of 600 to 250 angstroms and having large crystal grains can be obtained.

[Brief explanation of drawings]

FIGS. 1(a) to (e) are step-by-step cross-sectional views showing an embodiment of the method for manufacturing a crystalline semiconductor thin film of the present invention, and FIGS. 2(a) to 2(e) are
(c) and FIG. 3 are cross-sectional views showing an example of a conventional method for manufacturing a crystalline semiconductor thin film. 1... Insulating base 2... Amorphous Si film 3... Insulating film 4... Shielding film 5...-Racer beam 6... Microcrystalline Si film 7... Microcrystalline region 8 ...Groove region 9...More than polycrystalline St film

Claims (1)

[Claims] In a method for producing a crystalline semiconductor thin film in which a polycrystalline semiconductor film is obtained by crystallizing an amorphous semiconductor film formed on an insulating substrate, the amorphous semiconductor film is formed on the insulating substrate. After that, a step of laminating an insulating film and a shielding film having a groove region, a step of changing the amorphous semiconductor film into a microcrystalline semiconductor film by a laser beam incident from the groove region of the shielding film, and 1. A method for producing a crystalline semiconductor thin film, comprising the step of converting a semiconductor film into a polycrystalline semiconductor film by heat treatment at 500° C. or higher.