JPS5893222A - Preparation of semiconductor single crystal film - Google Patents

Abstract

PURPOSE:To make easy the lateral growth of epitaxial crystal and form a semiconductor single crystal film by depositing a metal or matal silicide at an aperture on an insulating film, depositing a polycrystal or amorphous semiconductor film thereon the thereafter irradiating a laser beam thereto. CONSTITUTION:An SiO2 film 2 is fomed on an Si substrate 1 by the general process, and an aperture is formed after removing a film 2 from the area where will be seed-crystallized. Then, a cobalt film 5 is vacuum-deposited in the specified thickness and the film 5 is removed from the area other than the aperture. Thereafter, a polycrystalline silicon film 3 is deposited by the CVD method under a reduced pressure. The silicon film 3 is annealed by irradiating electron beams or laser beams 4 on said silicon film 3. The silicon film 3 is easily single- crystallized through lateral epitaxial growth from the aperture.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a multilayer semiconductor device, and more particularly to a technique for epitaxial crystal growth from an underlying crystal portion to an upper semiconductor layer.

Prior Art and its Problems As is well known, semiconductor devices, especially integrated circuit elements, formed on a semiconductor substrate require oxidation, diffusion ion implantation, C
Devices were two-dimensionally arranged on a substrate using known techniques such as vD and photolithography. Therefore, there are limits to increasing the integration and speed of semiconductor devices using conventional techniques.

As a way to overcome this limit, a so-called three-dimensional multi-layer stacking of devices has been proposed, and polycrystalline silicon or amorphous silicon on an insulating film is used as the substrate material to realize this. A method in which I- is made into coarse crystal grains or single crystal by irradiation with an energy beam such as V-boo light or an electron beam, and then laminated is considered to be promising.

There are currently several proposed methods for manufacturing substrate materials used in multilayer semiconductor devices, but the most promising method is the IJ)8S method (Latera Wpita).
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As shown in Figure 1, in the LP01 method, a hole is formed in a part of the silicon substrate (1) and an insulating film (2), a polycrystalline or amorphous silicon film is deposited on the hole, and a continuous beam laser is applied. By irradiating with light or an electron beam, crystals are grown in the lateral direction from the contact portion of the -F geocrystalline silicon substrate at the opening as a seed crystal. In this case, the single crystal region (3) extends by about 100 μm at most from the opening ff1i. The advantage of this method is that a single crystal region can be formed at a desired location within the substrate plane by determining the seed crystal portion at position 11, as described above, and the semiconductor element can be formed at the F of the single crystal region, making it possible to form a single crystal region at a corner. It is a matter of

When growing a crystal film using the LESS method, the silicon group on the insulating film and the silicon group on the silicon substrate in the opening are heated due to differences in the thermal conductivity of their underlying materials, energy beam reflection, interference, etc. Since the conditions are different, it is difficult to create the optimum conditions for crystal growth for the entire silicon film.

In the case of laser beam irradiation, this is due to the reflection of light on the surface of the underlying insulating film, and in the case of electron beam irradiation, this is due to the influence of backscattered electrons returning from the underlying material to the silicon film. Generally, an insulating film has lower thermal conductivity than silicon, so the temperature of the silicon group on the insulating film increases more easily than that of the silicon film on the silicon substrate. For this reason, the entire energy beam irradiation l
-, the irradiation conditions will be too strong for the silicon film on the insulating film.

OBJECTS OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to facilitate epitaxial crystal growth.

SUMMARY OF THE INVENTION In the present invention, a thin metal film or metal silicide film is inserted between the silicon substrate in the opening and the silicon film deposited thereon, thereby allowing epitaxial crystal growth.

Effects of the Invention According to the present invention, it is possible to provide a method for manufacturing a semiconductor single crystal film in which the in-plane temperature distribution can be made gentle and lateral epitaxial crystal growth can be facilitated.

Embodiments of the invention to F, Examples of the invention will be explained using all the drawings-46o
2nd book! ``''IM E, this is a long side view of a lateral crystal. First, a silicon oxide film (2) is formed on a silicon substrate (1) by a normal process, and then the silicon oxide film (2) at the location where the seed crystal is to be formed is removed using a photographic method to form an opening. form. Next, a cobalt film (5) having a thickness of 200 mm is deposited by vacuum evaporation method V', and the cobalt film other than the openings is removed by photolithography. A polycrystalline silicon film (3) was deposited thereon by low pressure CVD. Silicon oxide film (2) and polycrystalline silicon film (,
The thicknesses of 3) are 0.5 μm and 0.3 μm, respectively. Next, the vicinity of the surface was heated by electron beam annealing to cause lateral crystal growth. The accelerating voltage of the electron beam is 10KV
, beam current 2 mA, and beam diameter approximately 100 μm. The electron beam was raster scanned over the surface at a scanning speed of % Cm/S.

As a result, a silicon film having a length of 500 μm and a width of 3011 m from the opening became a single crystal film having the same plane orientation as the underlying substrate. This is because, in addition to direct heating by the incident electron beam, backscattered electrons from the underlying cobalt layer contributed to the heating of the polycrystalline silicon film at the opening, which resulted in a temperature almost equivalent to that of the polycrystalline silicon film on the silicon oxide film. Because it became PLVC,
This is thought to be due to the temperature gradient in the in-plane lateral direction becoming gentler. On the other hand, it was clearly confirmed by measuring the elemental distribution in the depth direction using Auger single-molecule spectroscopy that cobalt milicide was formed in the cobalt layer by electron beam annealing. Therefore, ohmic contact between the underlying silicon substrate and the upper single crystal silicon film was easily obtained.

In this example, single crystallization by electron beam annealing was shown, but the same effect can be obtained by laser annealing. This phenomenon contributes to heating.

In addition, in this example, low pressure CV was used to form the polycrystalline silicon film.
Although method D was used, the same effect can be obtained by using vapor deposition in an ultra-high vacuum, sputtering, ion beam deposition, or the like. Although cobalt was used for the metal layer placed under the polycrystalline silicon film, other materials such as palladium, platinum, molybdenum, tungsten, niobium, nickel, etc. may also be used.

[Brief explanation of the drawing]

FIG. 1 is a sectional view for explaining the LESS method, and FIG. #T2 is a sectional view for explaining the present invention in detail. (1 other person) Figure 1 Figure 2

Claims (1)

[Claims] An insulating film is crushed on the surface of a single crystal semiconductor substrate, a part of the insulating film is removed to create an opening, a metal or metal silicide film is deposited on top of the insulating film, and a polycrystalline or amorphous film is formed on top of that. A method for manufacturing a semiconductor single crystal film, which comprises depositing a semiconductor film of high quality, and then epitaxially growing it laterally from the opening by irradiating it with a laser beam or a laser beam.