JPS61270293A - Production of semiconductor single crystal film - Google Patents

Abstract

PURPOSE:To improve the accuracy of graphoepitaxial growth, by depositing a polycrystal Ge film preferentially oriented in a specific direction on a grooved amorphous insulator substrate, and heat-treating the deposited polycrystal Ge film. CONSTITUTION:Grooves having a depth (h) and width (l) are formed at an interval (m) on the surface of an amorphous insulator film 2 formed on a substrate 1, and a polycrystal Ge film 3 preferentially oriented in <100> direction as the direction (Z) perpendicular to the substrate 1 is deposited thereon. The resultant Ge film 3 is then heat-treated below the melting point of Ge to promote the reorientation of the Ge crystal grains in the substrate surface and coalescence between the grains and form the aimed single crystal Ge film 3 so that the direction (Z) perpendicular to the substrate 1 and longitudinal direction (Y) of the grooves may be <100> direction.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing a semiconductor film used in the electronic device industry.

(Prior art and its problems) The conventional technology for forming a single-crystal Ge film on an amorphous insulator substrate is to form an insulator film such as Sin on the surface of a single-crystal Si substrate, and then open an opening in the 5ios film. After exposing the single crystal Si surface and depositing polycrystalline GeIN on the substrate, the Si
A method of controlling crystal orientation by seeding from the opening of a starvation film is known, as reported by Shioka et al., Journal of
Applied Physics (J, Appl, Phys,
) Volume 56.

336 pages, 1984). This method uses a so-called seed crystal, but in order to form a multilayer semiconductor film device, a method that does not use a seed crystal is desirable. As a conventional technology that does not use seed crystals.

A known example is the grapho-epitaxial growth method (Yonehara et al., Applied Physics Letters (Ap.
pl, Phys, Lett, )' Volume 45, 631
Hage, 1984). In this method, the starting polycrystalline G
e film, the vertical direction of the substrate is <iio> or <112
> orientation is used, and the purpose is to control the crystal orientation and promote single crystallization by the effect of grooves processed on the substrate surface, which is a feature of the so-called grapho-epitaxial growth method.

However, in the grapho-epitaxial growth method, it is desirable that the starting polycrystalline material has a texture structure (only the -axis direction is a specific crystal orientation), and the direction perpendicular to the substrate of the single crystal film to be formed is The more this uniaxial direction matches, the more the single crystallization is promoted. In the above-mentioned report by Yoneha et al., using a starting polycrystalline material that tends to have a <110> or <112> orientation in the vertical direction of the substrate, a 5-solid-state surface-
Due to the energy effect, the vertical direction of the substrate is <100>
Single crystallization is performed by changing the orientation. For this reason, there are still problems such as insufficient single crystallization and the problem of ordinary thin M (
When the film thickness is about 5000 Å), the above effect does not work, and even if graphite epitaxial growth is attempted, single crystal Ge11 is obtained, which is problematic.

(Object of the Invention) The present invention improves the drawbacks of the conventional examples, especially the necessity of using a hyperfermentation membrane, and uses a new <IQQ> texture structure as a starting polycrystalline material. By using the present invention, it is an object of the present invention to provide a method for manufacturing a semiconductor single crystal film, which aims to improve the precision of grapho-epitaxial growth.

(Structure of the Invention) According to the present invention, a single layer is formed on the surface of an amorphous insulator that is grooved for use in so-called grapho-epitaxial growth.
After depositing a polycrystalline Ge film in which the direction perpendicular to the substrate is preferentially oriented in the <100> orientation, the s'tl'-Ge film is heat-treated at a temperature below the melting point of Ge to increase the grain size of the crystal grains. , the crystal orientation alignment is controlled, and the vertical direction of the substrate and the longitudinal direction of the groove are in the <ioo> orientation.
A method for manufacturing a semiconductor single crystal film is obtained, which is characterized by forming a film.

(Detailed Description of the Structure) The present invention, having the above-described structure, has made it possible to form a single crystal G e J[d[ by grapho-epitaxial growth, which is superior to the conventional technique 4C. This will be explained below with reference to FIG.

FIG. 1 is a perspective view of a substrate structure used to explain the basic concept of the present invention.

First, the amorphous insulator film 2 is released on the substrate l, and then,
A groove consisting of the depth of the groove, 4@l of the groove, and the distance m between the grooves is formed by the insulator jI! , 2 was formed on the surface.

Next, a polycrystalline Ge film 3 with preferential orientation in the <100> direction (vertical to the substrate) is deposited, and then heat-treated at a temperature below the melting point of Qe.
The single-crystal Ge film 3 was formed by promoting the coalescence of rearranged particles of Ge crystal grains within the substrate plane so that the longitudinal direction of the Ge crystal grains (Z) and the longitudinal direction -) of the grooves were in the <100> orientation. At this time, based on the degree of freedom and correlation of the crystal axes, the longitudinal direction of the yeast (direction perpendicular to the force (increase <100>
It is clear that it is the direction.

(Central 'JIffA example) Below is the uninvented! The M example will be explained in detail with reference to FIG.

The substrates indicated by l are a Si substrate and a sapphire substrate.

An alumina substrate and an aluminum nitride substrate were used. As the amorphous insulator film shown in 2, S t O1 film & Si-Na
IK was used. The film thickness of the Jle edge film 2 was set to 1 ttm in the case of a Si film, Q and 2 μm in the case of @.

Next, grooves are formed on the surface of the insulating film 2 so that the depth thereof is 0.1.
Grooves with a rectangular cross section each having a groove width (a) of 1 Affi and a groove interval (e) of 0.15 .mu.m were processed using conventional ultraviolet lithography technology and dry etching technology.

A Ge film 3 was deposited on the substrate formed as described above by high frequency sputtering. As sputtering conditions,
Power: soW, deposition rate = 400 to 400°C, substrate heating temperature: room temperature to 600°C, and sputtering gas pressure in the range of 3 ml'orr using Ar gas.

Within the above sputtering condition range, the deposited Ge
It was found by evaluation using ultraviolet light reflection and X-ray diffraction that the film quality of film 3 is in an amorphous state at a substrate temperature of 300° C. or lower. When these amorphous Ge11 were crystallized at a temperature of about 650° C., which is 0.75 times the melting point on the absolute temperature scale, a randomly oriented polycrystalline Ge film was obtained. Substrate temperature 3
At temperatures above 00°C, a polycrystalline Ge film is obtained, and the substrate temperature is 4.
At around 00°C, the film is preferentially oriented in the <110> direction perpendicular to the substrate, and when the substrate temperature is around 500°C, the film is a mixture of <IQQ> and <110> directions perpendicular to the substrate, and when the substrate temperature is around 600°C, the film is oriented in the <110> orientation. Vertical direction is <100>
A film with preferential orientation was obtained.

It was deposited on an insulator film 2 that had been grooved.

The Ge film 3 having a film thickness of 0.6 μm was coated with 1.1 μm in an inert gas at a temperature of about 900° C., which is 0.95 times the melting point on the absolute temperature scale.
A heat treatment for ~4 hours is applied to promote the rearrangement and coalescence of crystal grains, resulting in so-called gravitational Ge.
A film was formed. Note that a 0.5 μm thick SiO film was used as the surface protective film.

When the GeHX formed as described above was evaluated by X@ diffraction method, electron beam diffraction method, and anisotropic etching method, the crystallographic structure of the starting material (GaM after depositing) was found to be vertical to the substrate.
When using a film preferentially oriented in the <100> direction, we found that so-called grapho-epitaxial growth occurs, and both the vertical direction (z) of the substrate and the longitudinal direction (support) of the groove are <
A single crystal Ge film with l Q Q> orientation was obtained.

This was described in this embodiment. Similar results were obtained using any of the substrates 1, Si, sapphire, alumina, and aluminum nitride substrates, and as the insulator a2.

Similar results were obtained using Sin, film% 8 is Na M. However, when a quartz glass substrate was used as the substrate, there was a very large mismatch in thermal expansion coefficient with the Ge film (the G'e film peeled off, and a continuous single crystal film could not be obtained).

Regarding the dependence on the underlying insulating film, better results were obtained when the 5ill film was used.

In addition to this example, when vacuum-deposited Geg formed at room temperature is used as the KGe film, it is in an amorphous state in the deposited state.
As a result of subsequent heat treatment, the polycrystalline film was in a randomly oriented state, and a Ge film thickness of 0.5 to 0.6 μm was unsuitable for graphite epitaxial growth.

(Effect of the invention) Conventionally, when trying to graphite epitaxially grow a Ge film using an in-phase regrowth method that performs heat treatment below the melting point, the film thickness has been reduced by 10%.
Using ultra-thin m with 0OA or less, so-called 30 stitches d-s
Single crystallization has been achieved by the surface-energy effect; however, as a starting material as in the present invention, Ge is preferentially oriented in the <100) direction perpendicular to the substrate.
Production of Ge single-crystal films by grapho-epitaxial growth, which has characteristics based on the phenomenon that crystal grains rearrange and coalesce quickly even in thin films with a normal film thickness of about 0.5 μm. Law is obtained.

As described in detail above, according to the present invention, it is possible to form a single crystal germanium semiconductor film more easily than the conventional method, and it has great economical effects when manufacturing semiconductor devices using a germanium single crystal thin film as a lamination substrate. bring about.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a substrate structure for explaining the present invention. l...Substrate, 2...Insulator film,
3... Germao 1 Figure

Claims (1)

[Claims] In graphoepitaxial growth of a germanium (Ge) semiconductor film, after depositing a polycrystalline Ge film preferentially oriented in the <100> direction in the direction perpendicular to the substrate on a grooved amorphous insulator substrate, The Ge film is heat-treated at a temperature below the melting point of Ge, so that the direction perpendicular to the substrate and the longitudinal direction of the groove are <
A method for manufacturing a semiconductor single crystal film, comprising forming a single crystal Ge film having a 100> orientation.