JPH05319997A - Production of single crystal silicon carbide - Google Patents

Abstract

PURPOSE:To provide a method for producing a single crystal silicon carbide in which the labor and time for slicing can be omitted and the crystallinity can further be prevented from deteriorating by slicing. CONSTITUTION:A plate 5 for regulating the growth direction of silicon carbide 6 is installed to grow the silicon carbide in the surface direction of the plate 5 in a method for producing the single crystal silicon carbide by thermally subliming powdery silicon carbide 4, recrystallizing the silicon carbide 4 on a substrate composed of a silicon carbide single crystal and growing the silicon carbide 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing single crystal silicon carbide, and more particularly to the production of single crystal silicon carbide which can save the trouble and time of slicing and can prevent the deterioration of crystallinity due to slicing. Regarding the method.

[0002]

2. Description of the Related Art Silicon carbide (SiC) is attracting attention as a material for environment-resistant devices because it is extremely stable thermally and chemically and has excellent radiation resistance. In particular, 6H-type SiC single crystal has a bandgap of about 3 eV at room temperature and is used as a blue light emitting diode material.

As a method for growing a SiC single crystal ingot, for example, "Vacuum, 30 volumes, pages 52 to 58 (1
987) ”, a so-called sublimation method is adopted, and a SiC single crystal substrate is obtained by slicing an ingot obtained by this sublimation method into a plate shape with a slicer.

The above-mentioned sublimation method, as shown in FIG.
-A SiC powder 4 as a raw material is put in a lower portion of a crucible 3 which is covered with a holder 1 to which a substrate 2 made of a SiC single crystal is fixed, and the SiC powder 4 is heated and sublimated by, for example, a high frequency induction method to obtain a low temperature substrate. 2 is brought into contact with gasified SiC to recrystallize the single crystal S on the substrate 2.
This is a method of growing iC6.

In the sublimation method, the crystal plane orientation of the substrate 2 is set to the a-axis direction, that is, the {1,1, -2,0} plane and the {1,0, -1,0} plane. Mature S
It has been reported that the iC single crystal 6 stably inherits the crystal polymorphism (6H form) of the substrate crystal ("Proceedings of the 52nd Annual Meeting of the Applied Physics Society of Japan", p. 309 (199).
1 year) Autumn ").

[0006]

By the way, SiC has a Mohs hardness of 9.2 to 9.3, which is second only to that of diamond.
Because of its mechanical strength, when slicing an ingot obtained by the sublimation method into a plate with a slicer, it is necessary to reduce the slicing speed as compared with silicon (Si) or gallium arsenide (GaAs). Moreover, even if the slicing speed is reduced, the blade of the slicer is significantly deteriorated or consumed, resulting in a high cost.

[0007] Further, by slicing for a long time, Si
It is also sufficiently concerned that the C single crystal substrate will be damaged and the crystallinity will deteriorate.

The present invention has been made in view of the above circumstances, and provides a method for producing single crystal silicon carbide capable of saving the labor and time of slicing and preventing deterioration of crystallinity due to slicing. The purpose is to

[0009]

DISCLOSURE OF THE INVENTION The present invention is a method for producing single crystal silicon carbide in which powdery silicon carbide is heated to sublimate and recrystallized on a substrate made of silicon carbide single crystal to grow silicon carbide. In (1), a plate for regulating the growth direction of silicon carbide is provided, and silicon carbide is grown into a plate shape having an arbitrary thickness.

[0010]

In order to regulate the growth direction of silicon carbide, for example, by arranging a plate of graphite carbon or porous carbon vertically to the substrate, silicon carbide can be grown in a plate shape having an arbitrary thickness.

Further, in the present invention, as described above,
The crystal plane orientation of the SiC single crystal substrate is perpendicular to the c-axis ({1,1, -2,0} plane or {1,0, -1,
0 plane), the c-axis ({0,0,0,1}
Or, there are few defects in {0,0,0, -1} plane, and it is possible to directly grow a plate-like silicon carbide single crystal of good quality of polymorph (6H type) with good reproducibility without slicing. You can

[0012]

EXAMPLE A method for producing single crystal silicon carbide according to an example of the present invention will be specifically described with reference to FIGS. 1 and 2.

In this method, SiC powder 4 as a raw material is put in the lower part of the crucible 3, and the crucible 3 is covered with a holder 1 to which a substrate 2 made of 6H-SiC single crystal is fixed on the lower surface, and then, for example, a high frequency induction method. This SiC powder 4 is heated to sublime.

When the substrate 2 is set to a low temperature part, gasified SiC is brought into contact with the substrate 2 to recrystallize the substrate 2 to form Si on the substrate 2.
The C single crystal 6 is grown.

A large number of plates 5 are provided near the surface of the substrate 2 and are arranged vertically with respect to the substrate 2 at a predetermined interval. These plates 5 are made of graphite carbon or porous carbon.

The growth direction of the SiC single crystal 6 grown on the substrate 2 is restricted by the plate 5, and the SiC single crystal 6 grows only in the direction perpendicular to the substrate 2 and becomes a plate shape. Therefore, a plate-shaped SiC single crystal substrate having a desired thickness and width can be obtained without slicing depending on the distance between the plates 5.

The crystal plane orientation of the SiC single crystal substrate thus obtained is determined by the crystal plane orientation of the substrate 2 supported by the holder 1. For example, the crystal plane orientation of the substrate 2 is a plane perpendicular to the c-axis. ({1,1, -2,0} plane or {1,0, -1,0} plane), so that the same crystal polymorph (6H-SiC) as the substrate 2 has a plane orientation in the c-axis direction. ({0,0,0,1} plane or {0,0,0, -1}
The plate-shaped SiC single crystal of (plane) grows stably.

Further, for example, the crystal plane orientation is {1,1,-
If the substrate 2 in which the (2,0) plane or the {1,0, -1,0} plane is tilted (turned off) by several degrees (for example, 3 to 5 °) is used, the {0,0,0,1} plane is obtained. Or {0,0,0,-
It is possible to obtain a plate-shaped SiC single crystal substrate having a plane orientation in which the 1} plane is off by several degrees.

Since the SiC single crystal substrate obtained as described above is formed to have an arbitrary thickness and width, it is not necessary to perform slicing or polishing for obtaining a crystal plane orientation.
The process time can be remarkably shortened, the blade of the slicer and the polishing material are not consumed, and the crystal plane is not damaged by the slicing.

[0020]

As described above, according to the method of the present invention, since silicon carbide is grown into a plate having a predetermined thickness using, for example, a plate whose growth direction is regulated, slicing can be arbitrarily performed. Plate-like SiC with various thickness and width
A single crystal substrate can be obtained, and a great amount of time and cost required for slicing can be saved.

Further, there is no risk of damage to the crystal plane due to slicing, and plate-like S having high crystallinity is obtained.
An iC single crystal substrate can be obtained.

Further, since a plate-shaped SiC single crystal substrate having a crystal plane turned off at an arbitrary angle can be obtained by appropriately setting the crystal plane orientation of the substrate, the plane orientation of the crystal plane can be adjusted. This eliminates the need for the polishing step and saves much time and cost.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an example of an apparatus used in a method of the present invention.

FIG. 2 is a bottom view of a holder and a plate of an apparatus used in the method of the present invention.

FIG. 3 is a vertical cross-sectional side view of an example of a device used in a conventional example.

[Explanation of symbols]

 2 Substrate 4 Powdered Silicon Carbide 5 Plate 6 SiC Single Crystal

Claims (2)

[Claims] 1. A method for producing single-crystal silicon carbide in which powdery silicon carbide is heated to sublimate and recrystallized on a substrate made of silicon carbide single crystal to grow silicon carbide. A method for producing single-crystal silicon carbide, which comprises providing a regulating plate and growing silicon carbide into a plate having an arbitrary thickness. 2. The crystal plane orientation of the substrate is {1, 1, -2,
0} plane and {1,0, -1,0} plane as {0,0,
The method for producing a single crystal silicon carbide according to claim 1, wherein a plate-like silicon carbide single crystal having a 0,1} plane or a {0,0,0, -1} plane is grown.