SEED CRYSTAL FIXING APPARATUS AND A METHOD FOR FIXING THE SEED CRYSTAL

Abstract

A seed crystal fixing apparatus for fixing the seed crystal on the seed crystal setting part of a reaction vessel with interposition of the adhesive, has a chamber configured to place the seed crystal setting part and form a hermetic atmosphere within the chamber; and a pressure part placed within the chamber for uniformly applying a pressure on the entire surface of the seed crystal.

Description

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1A shows a schematic illustration of the seed crystal fixing apparatus housing a seed crystal fixing part on which a seed crystal is fixed with interposition of an adhesive;

FIG. 1B shows a top view of the lower chamber.

FIG. 2 to FIG. 8 show the steps for fixing the seed crystal.

FIG. 9 shows a schematic illustration of a silicon carbide single crystal producing apparatus (a crucible).

FIG. 10 shows a magnified photograph of the surface of the silicon carbide single crystal obtained in the comparative example.

FIG. 11 shows a magnified photograph of the surface of the silicon carbide single crystal obtained in the example.

FIG. 12A shows a schematic illustration of the cross-section of a modified example of the seed crystal fixing apparatus housing the seed crystal fixing part on which the seed crystal is fixed with interposition of an adhesive.

FIG. 12B shows a top view of the lower chamber.

FIG. 13 shows a schematic illustration of a conventional method for fixing the seed crystal.

FIG. 14A shows a schematic illustration of the seed crystal fixing apparatus housing a seed crystal fixing part on which a seed crystal is fixed with interposition of an adhesive;

FIG. 14B shows a top view of the lower chamber.

FIG. 15 shows the steps for fixing the seed crystal.

Claims

1. A seed crystal fixing apparatus for fixing the seed crystal on the seed crystal setting part of a reaction vessel with interposition of the adhesive, comprising: a chamber configured to place the seed crystal setting part and form a hermetic atmosphere within the chamber; anda pressure part placed within the chamber for uniformly applying a pressure on the entire surface of the seed crystal.

2. The seed crystal fixing apparatus according to the claim 1, wherein the chamber has an upper chamber and a lower chamber configured to form a hermetic atmosphere when the upper chamber is mounted on the lower chamber.

3. The seed crystal fixing apparatus according to the claim 2, wherein the lower chamber has a guide for fixing the seed crystal setting part and the seed crystal.

4. The seed crystal fixing apparatus according to the claim 3, wherein the guide contacts the side face of the seed crystal at least at three points.

5. The seed crystal fixing apparatus according to the claim 1, wherein the pressure part is a flexible bag placed within the chamber for inflation and deflation upon charge and discharge of an air and for uniformly applying a pressure on the entire surface of the seed crystal in contact with the surface of the seed crystal upon inflation.

6. The seed crystal fixing apparatus according to the claim 5, wherein the flexible bag is composed of a rubber or resin.

7. The seed crystal fixing apparatus according to the claim 1 further comprising an evacuating part configured to evacuate gas within the chamber to form a reduced pressure within the chamber.

8. The seed crystal fixing apparatus according to the claim 1 further comprising a heating body for hardening the adhesive by heating.

9. A method of fixing a silicon carbide single crystal on a seed crystal fixing part, comprising: placing a silicon carbide single crystal on a seed crystal fixing part with interposition of an adhesive;applying a uniform pressure on the entire surface of the seed crystal by contacting a flexible bag which is inflatable and deflatable to the seed crystal by charging a gas into the flexible bag; andhardening the adhesive.

10. The method of fixing a silicon carbide single crystal on a seed crystal fixing part according to the claim 9 further comprising fixing a guide with the seed crystal fixing part, and applying the adhesive on the seed crystal fixing part except for the guide.

11. The method of fixing a silicon carbide single crystal on a seed crystal fixing part according to the claim 9, wherein the adhesive is hardened under the pressure.

12. A method of fixing a silicon carbide single crystal on a seed crystal fixing part, comprising: placing a silicon carbide single crystal on a seed crystal fixing part with interposition of an adhesive within a hermetic atmosphere; andforming the reduced pressure atmosphere within the hermetic atmosphere; andheat-hardening the adhesive.

13. The method of fixing a silicon carbide single crystal on a seed crystal fixing part according to the claim 12 further comprising fixing a guide with the seed crystal fixing part, and applying the adhesive on the seed crystal fixing part except for the guide.

14. The method of fixing a silicon carbide single crystal on a seed crystal fixing part according to the claim 12, wherein the pressure of the reduced pressure atmosphere is about 300 Torr or less.

15. The method of fixing a silicon carbide single crystal on a seed crystal fixing part according to the claim 12, wherein the heating temperature is in the range from about 100° C. to about 1000° C.