JPH046824A - Manufacture of crystalline semiconductor thin film - Google Patents

Abstract

PURPOSE:To obtain a manufacturing method which can control the position to generate a crystal nucleus and by which a crystal defect by a stress is hard to cause by a method wherein a semiconductor film containing impurities is laminated on a polycrystalline semiconductor film, it is left to be an island shape, an insulating film and a shielding film are laminated, the shielding film is left to be an island shape, a laser beam is irradiated and the polycrystalline semiconductor film and the semiconductor film are crystallized. CONSTITUTION:A polycrystalline semiconductor film which has been formed on an insulating substrate is recrystallized to obtain a crystalline semiconductor thin film; thereby, a crystalline semiconductor thin film is manufactured. In this case, a polycrystalline semiconductor film 2 is formed on an insulating substrate 1; after that, a semiconductor film 3 containing impurities is laminated; the semiconductor film 3 containing the impurities is left to be an island shape. Then, an insulating film 4 and a shielding film 5 with which said polycrystalline semiconductor film 2 and the semiconductor film 3 containing the impurities are covered are laminated; after that, the shielding film 5 is left to be an island shape. After that, said polycrystalline semiconductor film 2 and the semiconductor film 3 containing the impurities are irradiated with a laser beam 6; thereby, the polycrystalline semiconductor film 2 and the semiconductor film 3 containing the impurities are recrystallized.

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.
ator) structure.

[Prior art 1 A conventional example of a method for manufacturing a crystalline semiconductor thin film is disclosed in Japanese Patent Application Laid-Open No. 1983
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) 2 is formed on a quartz substrate 9 by low pressure vapor phase epitaxy, and then a Si film is formed as shown in FIG. 2(b). , a film (silicon dioxide film) 10 is first laminated, and then a laser beam 6 is irradiated to melt and crystallize the polycrystalline Si film 2 to form a single crystal Si 1m ( (single crystal silicon film) 11. Sin, the film io suppresses the flow of silicon that occurs when the polycrystalline S1 film 2 is melted during laser irradiation, and the surface of the single crystal Si film 11 solidified after cooling is flat compared to the case without the 5in2 film 10. It is said that it becomes.

[Problem to be solved by the invention 1 However, due to the irradiation of the laser beam 6, 5i02
tl! 10 and molten polycrystalline 5i) l! 2(7) causes crystal defects in the solidified single crystal Si film 11, resulting in a problem that a good quality film cannot be obtained. Furthermore, after the silicon film is melted by irradiation with the laser beam 6, crystal nuclei begin to form at random locations that cannot be controlled at all, and after cooling, large grains with uncontrolled crystal positions as shown in Figure 3 are formed. It is only converted into a polycrystalline Sl film 12 having crystals of . Therefore, the film quality becomes non-uniform.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for manufacturing a crystalline semiconductor thin film in which the position of crystal nuclei can be controlled and crystal defects due to stress are less likely to occur. .

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a crystalline semiconductor thin film according to the present invention recrystallizes a polycrystalline semiconductor film formed on an insulating substrate. In a method for producing a crystalline semiconductor thin film, the polycrystalline semiconductor film is formed on the insulating substrate, and then a semiconductor film containing impurities is laminated to form the semiconductor film containing impurities. A step of stacking the impurity-containing semiconductor film to leave it in an island shape; and after stacking an insulating film and a shielding film that cover the polycrystalline semiconductor film and the impurity-containing semiconductor film, the shielding film is left in an island shape. and a step of recrystallizing the polycrystalline semiconductor film and the semiconductor film containing impurities by irradiating the polycrystalline semiconductor film and the semiconductor film containing impurities with a laser beam. shall be.

[Example 1] Hereinafter, the method for manufacturing a crystalline semiconductor thin film according to the present invention will be described using SOI.
An example applied to the formation of a structure will be described with reference to the drawings.

First, a polycrystalline Si film 2 is formed on an insulating substrate 1 as shown in FIG. After laminating 3, the impurity-containing S1 film 3 is left in an island shape by photolithography, and after further laminating the insulating film 4, a shielding film 5 is laminated, and the shielding film 5 is left in an island shape by photolithography. Irradiate the laser beam 6. The laser beam 6 melts and recrystallizes the unshielded impurity-containing Si film 3 and polycrystalline Si film 2. At the time of melting, impurities spread into the melted region, and at the same time, the heat of fusion is conducted to the melted Zinocon film region where the laser beam 6 is shielded.
The stress-induced strain between the insulating film 4 and the silicon film that occurs during melting and recrystallization is alleviated, and crystal defects due to stress in the crystalline Si film 7 shown in FIG. 1(C) are less likely to occur. . In addition, as shown in FIG. 1(b), the block Wltli5
Since the area irradiated with the laser beam 6 is limited by this, large-sized crystal grains are formed only in the area directly irradiated with the laser beam 6. Also, Figure 1 (
As shown in C), the region irradiated with the laser beam 6 becomes an impurity diffusion region 8, so when impurity-containing 5111i 3 containing a large amount of hydrogen is used, the hydrogen in the film fills the crystal defects and The obtained crystalline Si film 7 has fewer defects and is of good quality.

[Effects of the Invention] As explained above, the method for manufacturing a crystalline semiconductor thin film of the present invention reduces the incidence of crystal defects caused by stress generated during the process, produces a high-quality film, and produces large grains in fixed positions. It has the effect of forming crystal grains with a large diameter.

[Brief explanation of drawings]

FIGS. 1(a) to (C) are step-by-step cross-sectional views showing an embodiment of the method for producing a crystalline semiconductor thin film of the present invention, and FIGS. 2(a) to (C) are
c) and FIG. 3 are cross-sectional views showing an example of a conventional method for manufacturing a crystalline semiconductor thin film.・Insulating substrate ・Polycrystalline Si film Impurity-containing Si film ・Insulating film ・Shielding film ・Laser beam ・Crystalline Si film ・Impurity diffusion region

Claims (1)

[Claims] In a method for producing a crystalline semiconductor thin film in which a crystalline semiconductor thin film is obtained by recrystallizing a polycrystalline semiconductor film formed on an insulating substrate, the polycrystalline semiconductor film is formed on the insulating substrate. After that, a step of stacking a semiconductor film containing impurities to leave the semiconductor film containing impurities in an island shape, and stacking an insulating film and a shielding film covering the polycrystalline semiconductor film and the semiconductor film containing impurities. After that,
leaving the shielding film in an island shape; and recrystallizing the polycrystalline semiconductor film and the impurity-containing semiconductor film by irradiating the polycrystalline semiconductor film and the impurity-containing semiconductor film with a laser beam. A method for producing a crystalline semiconductor thin film, the method comprising the steps of: