n-Type 4H—SiC single crystal substrate and method of producing n-type 4H—SiC single crystal substrate

Patent metadata

Field	Value
Publication number	US-11655561-B2
Application number	US-201916553302-A
Country	US
Kind code	B2
Filing date	Aug 28, 2019
Priority date	Aug 30, 2018
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

In an n-type 4H-SiC single crystal substrate of the present disclosure, the concentration of the element N as a donor and the concentration of the element B as an acceptor are both 3×1018/cm3 or more, and a threading dislocation density is less than 4,000/cm2.

First claim

What is claimed is:

1. An n-type 4H-SiC single crystal substrate in which a concentration of a donor element and a concentration of an acceptor element are both 3.0×10 18 /cm 3 or more, and a threading dislocation density is less than 4,000/cm 2 ,
wherein the threading dislocation includes threading screw dislocation, threading edge dislocation, and threading mixed dislocation.

2. The n-type 4H-SiC single crystal substrate according to claim 1 , wherein the concentration of the acceptor element is 3.0×10 18 /cm 3 or more and less than 2.0×10 19 /cm 3 .

3. The n-type 4H-SiC single crystal substrate according to claim 1 ,
wherein the acceptor element is boron (B).

4. The n-type 4H-SiC single crystal substrate according to claim 2 ,
wherein the acceptor element is boron (B).

5. The n-type 4H-SiC single crystal substrate according to claim 1 ,
wherein the donor element is nitrogen (N).

6. A method of producing an n-type 4H-SiC single crystal substrate according to claim 1 , comprising:
a process of filling a crucible with a raw material containing a silicon source (Si), a carbon source(C), and an element as an acceptor;
a process of pre-sublimating 0.1 mass% or more of the raw material in the crucible;
a process of disposing a seed crystal to face the raw material; and
a process of supplying a gas containing an element as a donor into the crucible, sublimating the pre-sublimated raw material in the crucible, and allowing a single crystal layer to grow on a surface of the seed crystal.

7. The method of producing an n-type 4H-SiC single crystal substrate according to claim 6 , wherein the acceptor is boron (B).

8. The method of producing an n-type 4H-SiC single crystal substrate according to claim 6 ,
wherein the donor is nitrogen (N).

Assignees

• Showa Denko Kk

Inventors

• SUO Hiromasa
• Eto Kazuma
• Kato Tomohisa

Classifications

• H10D62/8325

  Silicon carbide · CPC title

• H10D62/124

  Shapes, relative sizes or dispositions of the regions of semiconductor bodies or of junctions between the regions · CPC title

• C30B31/02 Primary

  by contacting with diffusion materials in the solid state · CPC title

• C30B23/02

  Epitaxial-layer growth · CPC title

• C01P2002/54

  one element only · CPC title