Method for producing SiC single crystal

Patent metadata

Field	Value
Publication number	US-9822468-B2
Application number	US-201615145050-A
Country	US
Kind code	B2
Filing date	May 3, 2016
Priority date	May 18, 2015
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

A method for producing a SiC single crystal by a solution process is provided, which allows generation of miscellaneous crystals to be reduced. Method for producing a SiC single crystal wherein a crucible has thickness Lu in horizontal direction at same height as liquid level of Si—C solution, and thickness Ld in horizontal direction at same height as bottom inner wall, Ld/Lu is 2.00 to 4.21, and thickness in horizontal direction of crucible monotonously increases between Lu and Ld from Lu toward Ld, wall thickness of crucible is 1 mm or greater, bottom thickness Lb in vertical direction of crucible is between 1 mm and 15 mm, bottom outer wall of crucible has flat section with area of 100 mm 2 or greater, depth of Si—C solution from bottom inner wall is 30 mm or greater, and method includes heating and electromagnetic stirring Si—C solution with high-frequency coil.

First claim

What is claimed is:

1. A method for producing a SiC single crystal in which a seed crystal substrate is contacted with a Si—C solution that is placed in a crucible and has a temperature gradient such that the temperature decreases from the interior toward the liquid level, for growth of a SiC single crystal, wherein:
the crucible has a thickness Lu in the horizontal direction of the crucible at the same height as the liquid level of the Si—C solution, and a thickness Ld in the horizontal direction of the crucible at the same height as the bottom inner wall of the crucible, the ratio Ld/Lu of Ld to Lu being 2.00 to 4.21, and the thickness in the horizontal direction of the crucible increasing in a monotonous manner between the thickness Lu and the thickness Ld, from the thickness Lu toward the thickness Ld,
the wall thickness of the crucible is 1 mm or greater,
the thickness Lb in the vertical direction of the bottom section of the crucible is between 1 mm and 15 mm,
the bottom outer wall of the crucible has a flat section, the area of the flat section being 100 mm 2 or greater,
the depth of the Si—C solution placed in the crucible from the bottom inner wall of the crucible is 30 mm or greater, and
the method comprises heating and electromagnetic stirring of the Si—C solution with a high-frequency coil situated on the periphery of the crucible.

2. The method for producing a SiC single crystal according to claim 1 , wherein:
the crucible has a support member situated under the bottom section of the crucible,
the support member is made of the same material as the crucible,
at least a portion of the end of the support member is bonded to at least a portion of the bottom section of the crucible,
the ratio Lzo/OD, of the outer diameter Lzo of the support member with respect to the outer diameter OD of the crucible, is no greater than 0.25, and
the outer diameter Lzo of the support member is 10 mm or greater and the length is 5 mm or greater.

Assignees

• Toyota Motor Co Ltd
• Nippon Steel & Sumitomo Metal Corp

Inventors

• Daikoku Hironori
• Kamei Kazuhito
• Kusunoki Kazuhiko
• Seki Kazuaki
• Kishida Yutaka

Classifications

• C30B29/36 Primary

  Carbides · CPC title

• C30B9/06

  using as solvent a component of the crystal composition · CPC title

• H10D62/80

  characterised by the materials · CPC title

• C30B19/12

  characterised by the substrate · CPC title

• C30B15/14

  Heating of the melt or the crystallised materials · CPC title