Surface treatment method for single crystal SiC substrate, and single crystal SiC substrate

Patent metadata

Field	Value
Publication number	US-9570306-B2
Application number	US-201314435383-A
Country	US
Kind code	B2
Filing date	Nov 15, 2013
Priority date	Nov 16, 2012
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

The present application aims to provide a surface treatment method that is able to accurately control the rate of etching a single crystal SiC substrate and thereby enables correct understanding of the amount of etching. In the surface treatment method, the single crystal SiC substrate is etched by a heat treatment performed under Si vapor pressure. At a time of the etching, inert gas pressure in an atmosphere around the single crystal SiC substrate is adjusted to control the rate of etching. Accordingly, correct understanding of the amount of etching is obtained.

First claim

The invention claimed is:

1. A method for treating a surface of a single crystal SiC substrate, comprising
an ion implanting step of implanting ions in the single crystal substrate,
etching the single crystal SiC substrate by heat treatment under Si vapor pressure and controlling the rate of etching by adjusting inert gas pressure of an atmosphere around the single crystal SiC substrate,
wherein the rate of etching is 1000 nm/min or less, and
wherein in the etching step about several tens of nm from the surface of an insufficient ion-implanted portion of the single crystal SiC substrate having an insufficient ion concentration of implanted ions is removed.

2. The method for treating the surface of the single crystal SiC substrate according to claim 1 , wherein
the single crystal SiC substrate is treated in a crucible-made of tantalum metal, and
a tantalum carbide layer is exposed to an internal space of the crucible.

3. The method for treating the surface of the single crystal SiC substrate according to claim 1 , wherein
in the etching step, the ions implanted in the single crystal SiC substrate are activated while the insufficient ion-implanted protion is removed.

4. The method for treating the surface of the single crystal SiC substrate according to claim 1 , wherein
the etching step is performed on the single crystal SiC substrate whose surface is exposed without being covered with any carbon layer.

5. The method for treating the surface of the single crystal SiC substrate according to claim 1 , wherein
the rate of etching is 100 nm/min or less.

6. The surface treatment method for treating the surface of the single crystal SiC substrate according to claim 1 , wherein
the etching step is performed on the single crystal SiC substrate before an epitaxial layer is formed thereon.

7. The method for treating the surface of the single crystal SiC substrate according to claim 1 , wherein
the inert gas pressure is 10 Pa or more.

8. A method for treating a surface of a single crystal SiC substrate, in which the single crystal SiC substrate is etched by performing a heat treatment under Si vapor pressure,
the method comprising
an etching step of controlling the rate of etching by adjusting inert gas pressure of an atmosphere around the single crystal SiC substrate, wherein
the single crystal SiC substrate has an off angle relative to a (0001) face,
wherein in the etching step, the heat treatment is performed on the single crystal SiC substrate in an atmosphere of an inert gas and Si, to remove macro-step bunching during the treatment performed on the surface of the single crystal SiC substrate and about several tens of nm from the surface of an insufficient ion-implanted portion of the surface of the single crystal SiC substrate having an insufficient ion concentration of implanted ions is removed.

9. The method for treating the surface of the single crystal SiC substrate according to claim 8 , wherein
the inert gas pressure is adjusted so as to set the rate of etching to 100 nm/min or more.

10. The method for treating the surface of the single crystal SiC substrate according to claim 8 , wherein
the inert gas pressure is adjusted so as to set the rate of etching to 1000 nm/min or less.

11. The method for treating the surface of the single crystal SiC substrate according to claim 8 , wherein
the inert gas pressure at a time of removal of the macro-step bunching is, at least temporarily, set to 0.5 Pa or more and 10 Pa or less.

12. The method for treating the surface of the single crystal SiC substrate according to claim 8 , wherein
an insufficient ion-implanted portion of the surface of the single crystal SiC substrate and the macro-step bunching are removed simultaneously.

Assignees

• Toyo Tanso Co

Inventors

• Torimi Satoshi
• Yabuki Norihito
• Nogami Satoru

Classifications

• H10P50/242

  of Group IV materials · CPC title

• C30B33/12 Primary

  in gas atmosphere or plasma · CPC title

• C30B33/02

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

• C30B33/08

  Etching · CPC title

• C30B31/22

  by ion-implantation · CPC title