JPH02130917A - Manufacture of semiconductor film - Google Patents

Abstract

PURPOSE:To grow a semiconductor film having a thickness of necessary aspect ratio by forming a cavity part having a previously set aspect ratio, and selectively performing an epitaxial growth only on the cavity part. CONSTITUTION:On the surface of a P-type Si substrate 12, SiO2 film 14 is formed in a specified thickness by wet oxidation; an aperture 15 is formed in the film 14 by lithography art, and the substrate 12 is exposed; an epitaxial growth Si film 13 is selectively grown only in the aperture part 15; a polycrystalline Si film 17 is deposited in a specified thickness; an island-shaped film 17 having a necessary transversal dimension is formed by lithography art; an SiO2 film 19 is deposited on the whole substrate surface, and an aperture part 21 is formed in a film 19; the film 17 only is selectively subjected to gas etching, and a transversal epitaxial growth Si film 25 is selectively grown in the cavity part 23 having a specified aspect ratio. Finally the film 19 is exfoliated, thereby forming an Si film having a desired area.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor film. [Prior Art] In the method for manufacturing a semiconductor film that has been used conventionally, St.
An O□ film is formed on a predetermined portion, and epitaxial growth is selectively performed only on the exposed portion of the semiconductor layer in a predetermined region.
Furthermore, a method of performing lateral overgrowth on the SlO□ film is known (J, Appl.

Phys, 55 (2>15. January 1984
+p, 519. Control
l epitaxial chemical vapo
r depositionof 5ilicon ov
er 1 nsulators).

[Problem to be solved by the invention]

In conventional technology, SOI (
Ses+1 conductor On In5ulat
When obtaining the structure (or), growth proceeds in unnecessary vertical directions, making it impossible to obtain a thin grown film.

An object of the present invention is to provide a method for manufacturing a semiconductor film that solves this problem.

[Means to solve the problem]

The method for manufacturing a semiconductor film of the present invention includes forming a first insulating film on a semiconductor substrate, forming a first opening that exposes the semiconductor substrate, and selectively opening only the first opening. A first semiconductor epitaxial growth film is grown, a polycrystalline Si film is deposited on the first insulating film and the first semiconductor epitaxial growth film, and the polycrystalline Si film is deposited on the first insulating film and the first semiconductor epitaxial growth film.
forming a second insulating film on the film, forming a second opening in the second insulating film so that the polycrystalline Si film is exposed;
The polycrystalline Si film sandwiched between the first and second insulating films is
The method is characterized in that a cavity is formed by selectively etching the opening, and a second semiconductor epitaxial growth film is selectively grown laterally in the cavity.

[Effect]

With conventional semiconductor film manufacturing technology, it is impossible to obtain a thin film due to excessive growth in the vertical direction. This is because growth is performed under conditions where the raw material gas concentration distribution is approximately the same in both the vertical and horizontal directions. The crystal growth rate depends on the plane orientation. As a result, even if the vertical and horizontal growth surfaces are selected as different surfaces, the ratio of the growth rate of each surface becomes the same value as the aspect ratio, and a larger aspect ratio cannot be obtained.

In contrast, in the present invention, by forming a cavity having a predetermined aspect ratio and performing epitaxial growth selectively only in the cavity, a semiconductor film having a thickness with a required aspect ratio is grown. It makes it possible.

〔Example〕

Examples of the present invention will be described below using schematic diagrams. FIG. 1 is a schematic cross-sectional diagram showing the process steps of the embodiment. As shown in FIG.
The O□ film 14 is oxidized at a temperature of 950°C.

~5000 formed by wet oxidation.

Next, as shown in FIG. 1(b), a first opening 15 is formed in the first SiO□ film 14 using lithography technology, exposing the p-type silicon substrate 12, and opening the first opening 15.
The first epitaxially grown Si film 13 is selectively grown only on the
, growth temperature 850°C + SI HzCI, flow rate 300cc/mtn, HCl flow M500cc/m
in, at a pressure of 30 Torr.

Next, as shown in FIG. 1(C), a polycrystalline Si film 17 is deposited at a substrate temperature of 600° C., SiH, and a flow rate of 150 cc/min.
The polycrystalline Si film 17 is deposited under conditions of a pressure of about 3,000 Torr to form an island-like polycrystalline Si film 17 having a required lateral size using lithography technology.

Next, as shown in FIG. 1(d), a second StO film 19 is deposited on the entire surface of the substrate including the polycrystalline Si film 17, and a second opening 21 is formed in the second 5tot film 19 by lithography. was formed, and the substrate temperature was 850℃.

HCl! Flow rate 500cc/min, pressure
Selective gas etching is performed only on the polycrystalline Si film 17 at 30 Torr to form a cavity portion 23 with a preset aspect ratio.
form.

Next, as shown in FIG. 1(e), a second epitaxially grown Si film 25 is selectively grown laterally in the cavity portion 23 at a growth temperature of 850° C. using SiH, Cj2. Flow rate 300c
c/ml n, HCl flow rate 500c/m i
n, grown at a pressure of 30 Torr.

Finally, as shown in FIG. 1(f), the second St0! Membrane 1
By peeling off 9, a thin Si film having a desired area can be formed.

Although gas etching was used as a method for forming the cavity in the above embodiments, it is also possible to form it by other methods (such as wet etching) that can selectively etch only the polycrystalline film. Needless to say.

(Effects of the Invention) By applying the present invention, it becomes possible to form a single crystal semiconductor film with a required thickness on an oxide film.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a process for forming a semiconductor film according to an embodiment of the present invention. 12...p-type silicon substrate 13...first epitaxial growth 3i film 14...
...First SiO□ film 15...First opening 17...Polycrystalline Si film 19...Second SiO□ film 21...Second opening 23.・Cavity portion 25・ ・Second epitaxially grown St film

Claims (1)

[Claims] (1) After forming a first insulating film on a semiconductor substrate, a first opening exposing the semiconductor substrate is formed, and a first semiconductor epitaxial growth film is selectively formed only in this first opening. A polycrystalline Si film is deposited on the first insulating film and the first semiconductor epitaxially grown film, a second insulating film is formed on the polycrystalline Si film, and the second insulating film is A second opening is formed to expose the polycrystalline Si film, and the polycrystalline Si film sandwiched between the first and second insulating films is selectively etched from the second opening to form a cavity. 1. A method for manufacturing a semiconductor film, comprising forming a second semiconductor epitaxially grown film selectively in the cavity and laterally growing a second semiconductor epitaxial growth film.