JPS63107894A - Formation of thin semiconductor film - Google Patents

Abstract

PURPOSE:To form a thin semiconductor film of a large area from a seed in one direction when a so-called SOI film is formed, by radiating energy beams on the seed in part of an insulating film in one direction to deposit a semiconductor film and by carrying out epitaxial growth on the film. CONSTITUTION:A sample having an opening (seed) 3 in part of an insulating film (oxide film) 2 formed on a single crystal semiconductor substrate (silicon substrate) 1 is put in a gas contg. semiconductor atoms for forming a film. Energy beams (ion beams) 5 are radiated on the opening 3 in the insulating film 2 in one direction under heating to deposit a semiconductor film 4 on the film 2 from the opening 3. A semiconductor film is further formed on the film 4 by epitaxial growth.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a single crystal semiconductor thin film on an amorphous insulating film.

[Prior Art] When forming a single crystal film, a so-called SOI film, on an insulating film, there is a method of forming an opening in a part of the insulating film and providing a so-called seed for transmitting crystal information from a single crystal substrate. S
This is effective in controlling the crystal orientation of the OI film.

[Problems to be Solved by the Invention] However, for example, if an oxide film is formed as an insulating film on a single-crystal 3i substrate, an opening is formed in a part of the oxide film, and amorphous Si is deposited thereon, When heat treatment is performed at a low temperature of 600° C. and the in-phase growth is performed laterally from the opening, that is, the seed portion, on the insulating film, the distance from the seed to the laterally growing single crystal is determined by the distance that impurities are introduced into the amorphous 3i. If it is not, there is a problem that it is only about 10 μ (References, H, 15 Hibara et al;
Extended Abstracts of the
18th Conference on 5olid
5tateDevices and Materia
ls, Tokyo, 1986 p553).

An object of the present invention is to solve the above-mentioned problems and provide a method for forming a semiconductor thin film that enables the formation of a single crystal thin film over a large area in one direction from a seed when growing an SOI crystal. .

[Means for Solving the Problems] The present invention introduces a sample having an opening in a part of an insulating film formed on a single crystal semiconductor substrate into a gas containing semiconductor atoms for film formation, and irradiating an energy beam in one direction from an opening in the insulating film while heating the insulating film, and depositing a semiconductor film on the insulating film through the opening, and epitaxially growing the semiconductor film on the sample formed in the above step. A semiconductor thin film forming method is characterized in that it includes a step of forming a semiconductor thin film.

[Function] When an amorphous film attached to an insulating film is grown in a solid phase in the lateral direction from a seed, the reason why there is a limit to the distance that the amorphous film can grow in the lateral direction from the seed is because the entire amorphous film is grown in a solid phase. Because it is heated to the growth temperature, polycrystalline nuclei grow locally, and the grown polycrystals collide with the in-phase grown film, thereby blocking in-phase growth. Therefore, in order to increase the lateral growth distance from the seed, instead of depositing a film all over the insulating film at once and then crystallizing it, it is sufficient to grow the film sequentially from the seed. In this method, a sample heated to a low temperature is placed in a gas containing film-forming atoms, and an electron beam is emitted in one direction from the seed part.
There is a method of irradiating an energy beam, such as a laser beam or an ion beam, and growing a film only in the area irradiated with the beam. However, with this method, it takes time to form a film with a thickness of about 1 μM, and the surface condition deteriorates, so first a film with a thickness of several tens of nanometers is formed using the method described above, and then epitaxial growth is performed on the film. SO with good surface condition and arbitrary film thickness can be formed by
It becomes possible to form an I film.

[Examples] Hereinafter, the present invention will be explained in more detail based on Examples. FIG. 1 shows the sample structure used in the present invention. In the figure, one layer of thermal oxide film 2 is formed on a silicon substrate 1 in the (100) orientation. Next, the seed portion 3 is selectively filled with silicon single crystal and planarized.

The sample is heated to 350° C. by the substrate heating device 6.

A mixed gas of silane and argon is introduced here, and then the ion beam 5 is moved from the seed 3 in one direction over the oxide film 2. Sl was used as the ion beam. When the ion beam 5 is first irradiated onto the seed 3, the seed 3
The silane gas present above is decomposed and silicon is deposited on the seeds 3. The effect of ions from the ion beam 5 simultaneously irradiated on the seed region is also added, and silicon grows epitaxially on the seed 3. Next, ion beam 5
When the ion beam 5 is gradually moved from the seed 3, similarly, silicon adheres only to the area irradiated with the ion beam 5. At this time, if the substrate temperature is high, the growth rate of polycrystals is fast, so depending on the conditions, a polycrystalline silicon film may grow.
By lowering the substrate temperature (by lowering the growth rate of polycrystalline nuclei), silicon atoms grow epitaxially and laterally in the growth layer 4. In the case of the present invention, the film thickness is several 1 onm. However, it is possible to form a thick film if it takes a long time.However, in that case, the surface condition deteriorates and the unevenness becomes severe.
In order to obtain a film thickness of approximately 100 nm, first, an ion beam is irradiated to form a silicon layer with a thickness of several tens of nanometers.

Ru. Next, silicon was epitaxially grown on the film to a predetermined thickness, thereby forming a silicon film that grew in a short time and had a good surface condition. Furthermore, similar effects can be obtained using a laser beam or an electron beam, and it has been found that energy beams are effective for film formation.

Furthermore, by linearizing the energy beam, high throughput can be achieved. In fact, when using an electron beam, it is possible to extract a linear electron beam with a length of approximately 4 to 5 cm, and by using such a beam, wafer processing can be performed more easily than with conventional methods. It was possible to shorten the time by about 50 times.

[Effects of the Invention] As described above, by using the method of the present invention, a semiconductor thin film with a large area can be formed in one direction from a seed, and since the beam shape of the energy beam can be easily shaped, a linear beam can be formed. However, the use of the linear beam has the effect of shortening the wafer processing time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the sample used in this example.

Claims (1)

[Claims] (1) A sample having an opening in a part of an insulating film formed on a single crystal semiconductor substrate is introduced into a gas containing semiconductor atoms for film formation, and while heating the sample, the insulating film is opened. irradiating an energy beam in one direction from the opening to deposit a semiconductor film on the insulating film through the opening; and epitaxially growing the semiconductor film on the sample formed in the step. Method for forming semiconductor thin films.