Method for preparing SiC single crystal

Patent metadata

Field	Value
Publication number	US-10612154-B2
Application number	US-201815945896-A
Country	US
Kind code	B2
Filing date	Apr 5, 2018
Priority date	Apr 14, 2017
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

A SiC single crystal is prepared by the solution process of placing a seed crystal in contact with a Si—C solution in a crucible and letting a SiC single crystal to grow from the seed crystal. The method includes the first growth step of conducting crystal growth using (0001) or (000-1) plane of a SiC single crystal of which the seed crystal is composed, as the growth surface, and the second growth step of conducting crystal growth using (1-100) or (11-20) plane of a SiC single crystal resulting from the first growth step as the growth surface. A SiC single crystal of high homogeneity and quality is obtained, which is reduced in threading screw dislocations, threading edge dislocations, basal plane dislocations, micropipes, and stacking faults.

First claim

The invention claimed is:

1. A method for preparing a SiC single crystal by the solution process of placing a seed crystal in contact with a Si—C solution in a crucible and letting a SiC single crystal to grow from the seed crystal, the method comprising:
the first growth step of conducting crystal growth using (0001) or (000-1) plane of a SiC single crystal of which the seed crystal is composed, as the growth surface, and
the second growth step of conducting crystal growth using (1-100) or (11-20) plane of a SiC single crystal resulting from the first growth step as the growth surface.

2. The method of claim 1 , further comprising the step of cutting (1-100) or (11-20) plane out of the SiC single crystal resulting from the first growth step, prior to the second growth step.

3. The method of claim 1 wherein, in the second growth step, (1-100) or (11-20) plane of a portion of the SiC single crystal resulting from the first growth step that has grown in the first growth step is made the growth surface.

4. The method of claim 1 , further comprising the step of cutting (0001) or (000-1) plane out of the SiC single crystal of which the seed crystal is composed, prior to the first growth step.

5. The method of claim 1 wherein the Si—C solution contains at least one metal element M selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Ho, Lu, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, Ga, Ge, Sn, Pb, and Zn.

6. The method of claim 5 wherein the Si—C solution contains the metal element M in a content of 1 to 80 at % based on the total of Si and M.

7. The method of claim 1 wherein the crucible is a graphite or SiC crucible.

8. The method of claim 7 wherein the crucible is a SiC crucible having an oxygen content of up to 100 ppm.

9. A method of claim 1 wherein, in the first growth step, the seed crystal is pulled upward from the Si—C solution in the crystal growing direction on the (0001) or (000-1) plane.

10. A method of claim 9 wherein, in the first growth step, said (0001) or (000-1) plane of a SiC single crystal of which the seed crystal is composed is placed in a horizontal direction perpendicular to the crystal growing direction.

11. A method of claim 9 wherein, in each of the first and second growth steps, the seed crystal is pulled upward from the Si—C solution at a rate of 10 to 2,000 μm/hr.

12. A method of claim 1 wherein, in the second growth step, the SiC single crystal resulting from the first growth step is pulled upward from the Si—C solution in the crystal growing direction on the (1-100) or (11-20) plane.

13. A method of claim 12 wherein, in the second growth step, said (1-100) or (11-20) plane of the SiC single crystal resulting from the first growth step is placed in a horizontal direction perpendicular to the crystal growing direction.

Assignees

• Shinetsu Chemical Co

Inventors

• Shinya Naofumi
• Hamaguchi Yu
• Yamagata Norio
• Minowa Takehisa

Classifications

• C30B19/04 Primary

  the solvent being a component of the crystal composition · CPC title

• C30B1/02 Primary

  by thermal treatment, e.g. strain annealing (C30B1/12 takes precedence) · CPC title

• C30B29/36

  Carbides · CPC title

• C30B19/12

  characterised by the substrate · CPC title

• C30B33/02

  Heat treatment (C30B33/04, C30B33/06 take precedence) · CPC title