SiC single crystal and method for producing same

• US 10,450,671 B2
• Filed: 08/27/2014
• Issued: 10/22/2019
• Est. Priority Date: 09/27/2013
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Daikoku, Hironori, Kado, Motohisa, Kamei, Kazuhito, Kusunoki, Kazuhiko
• Primary Examiner(s): Qi, Hua
• Application Number:
  US15/023,981
• Publication Number:
  US 20160237590A1
• Time in Patent Office: 1,882 Days
• CPC Class Codes: C30B 19/02 using molten solvents, e.g. flux
• CPC Class Codes: C30B 19/062 Vertical dipping system
• CPC Class Codes: C30B 19/068 Substrate holders
• CPC Class Codes: C30B 19/08 Heating of the reaction chamber or the substrate
• CPC Class Codes: C30B 19/10 Controlling or regulating controlling or regulating in general G05
• CPC Class Codes: C30B 19/12 characterised by the substrate
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: C30B 9/10 Metal solvents
• CPC Class Codes: H01L 21/02529 Silicon carbide
• CPC Class Codes: H01L 21/02598 monocrystalline
• CPC Class Codes: H01L 21/02609 Crystal orientation
• CPC Class Codes: H01L 21/02628 using solutions
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/1608 Silicon carbide

Abstract

Provided is a SiC single crystal that has a large growth thickness and contains no inclusions. A SiC single crystal grown by a solution process, wherein the total length M of the outer peripheral section formed by the {1-100} faces on the {0001} growth surface of the SiC single crystal, and the length P of the outer periphery of the growth surface of the SiC single crystal, satisfy the relationship M/P≤0.70, and the length in the growth direction of the SiC single crystal is 2 mm or greater.

Claims

1. A method for producing a SiC single crystal in which a SiC seed crystal substrate having a {0001} face,

the SiC seed crystal substrate being held on a center portion of a seed crystal holding shaft, the seed crystal holding shaft including the center portion and a side portion that surrounds the center portion, the side portion having alternating recesses and raised sections, is contacted with a Si—

C solution in a crucible,

the Si—

C solution having a temperature gradient such that a temperature of the Si—

C solution decreases from an interior of the Si—

C solution toward a surface of the Si—

C solution, to grow the SiC single crystal from the {0001} face of the SiC seed crystal substrate in a <

11-20>

direction and <

1-100>

direction and form a grown SiC single crystal, wherein the method comprises;

growing the SiC single crystal from the {0001} face of the SiC seed crystal substrate to a length of 2 mm or greater in the growth direction to form the grown SiC single crystal, and

prior to growing the SiC single crystal, configuring the seed crystal substrate and the seed crystal holding shaft to reduce heat loss from the <

11-20>

direction to be lower than heat loss from the <

1-100>

direction by bonding a top face of the seed crystal substrate to the center portion of the seed crystal holding shaft so that

the <

1-100>

direction of the seed crystal substrate is oriented to coincide with the recesses of the seed crystal holding shaft, and

the <

11-20>

direction of the seed crystal substrate is oriented to coincide with the raised sections of the seed crystal holding shaft;

wherein

a ratio S/C of a diameter S of the SiC seed crystal substrate to an inner diameter C of the crucible satisfies a relationship 0.50≤

S/C<

1.0.

2. The method for producing a SiC single crystal according to claim 1, wherein:

a total length M of an outer peripheral section formed by the {1-100} faces on the {0001} growth surface of the grown SiC single crystal, and a length P of an outer periphery of the growth surface of the grown SiC single crystal, satisfy the relationship M/P≤

0.70.

3. The method for producing a SiC single crystal according to claim 2, wherein the grown SiC single crystal has a concave crystal growth surface.

4. The method for producing a SiC single crystal according to claim 3, wherein the maximum angle θ

of the inclination of the concave crystal growth surface with respect to the onset axis plane of growth of the grown SiC single crystal is in the range of 0<

θ

≤

8°

.

5. The method for producing a SiC single crystal according to claim 1, wherein the method comprises forming a meniscus between the SiC seed crystal substrate and the Si—

C solution.

6. The method for producing a SiC single crystal according to claim 5, wherein the method comprises controlling the temperature of the Si—

C solution so that a temperature of the Si—

C solution at the outer peripheral sections directly below an interface with the crystal growth surface is lower than a temperature of the Si—

C solution at the center section directly below the interface with the crystal growth surface, and causing flow of the Si—

C solution from the center section to the outer peripheral sections directly below the interface with the crystal growth surface.

7. The method for producing a SiC single crystal according to claim 1, wherein the method comprises controlling the temperature of the Si—

C solution so that a temperature of the Si—

C solution at the outer peripheral sections directly below an interface with the crystal growth surface is lower than a temperature of the Si—

C solution at the center section directly below the interface with the crystal growth surface, and causing flow of the Si—

C solution from the center section to the outer peripheral sections directly below the interface with the crystal growth surface.

8. The method for producing a SiC single crystal according to claim 1, wherein the SiC single crystal is grown by having the Si—

C solution wet only the bottom face of the seed crystal substrate, forming a meniscus for crystal growth.

9. The method for producing a SiC single crystal according to claim 1, wherein no inclusions are present throughout the entire grown SiC single crystal.