Method of manufacturing silicon carbide semiconductor substrate and method of manufacturing silicon carbide semiconductor device

Patent metadata

Field	Value
Publication number	US-9633840-B2
Application number	US-201615152347-A
Country	US
Kind code	B2
Filing date	May 11, 2016
Priority date	Feb 7, 2013
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A step of preparing a silicon carbide substrate (S 11 ), a step of forming a first silicon carbide semiconductor layer on the silicon carbide substrate using a first source material gas (S 12 ), and a step of forming a second silicon carbide semiconductor layer on the first silicon carbide semiconductor layer using a second source material gas (S 13 ) are provided. In the step of forming a first silicon carbide semiconductor layer (S 12 ) and the step of forming a second silicon carbide semiconductor layer (S 13 ), ammonia gas is used as a dopant gas, and the first source material gas has a C/Si ratio of not less than 1.6 and not more than 2.2, the C/Si ratio being the number of carbon atoms to the number of silicon atoms.

First claim

The invention claimed is:

1. A method of manufacturing a silicon carbide semiconductor substrate, comprising steps of:
preparing a silicon carbide substrate;
forming a first silicon carbide semiconductor layer on the silicon carbide substrate using a first source material gas; and
forming a second silicon carbide semiconductor layer on the first silicon carbide semiconductor layer using a second source material gas,
wherein an impurity concentration in the first silicon carbide semiconductor layer is higher than an impurity concentration in the second silicon carbide semiconductor layer,
in the step of forming a first silicon carbide semiconductor layer and the step of forming a second silicon carbide semiconductor layer, ammonia gas being used as a dopant gas, the first source material gas having a C/Si ratio of not less than 1.6 and not more than 2.2, the C/Si ratio being the number of carbon atoms to the number of silicon atoms,
a flow rate of the first source material gas being different from a flow rate of the second source material gas.

2. The method of manufacturing a silicon carbide semiconductor substrate according to claim 1 , wherein
the thickness of the first silicon carbide semiconductor layer is smaller than the thickness of the second silicon carbide semiconductor layer.

3. The method of manufacturing a silicon carbide semiconductor substrate according to claim 1 , wherein
the first source material gas and the second source material gas each contain monosilane and propane.

4. The method of manufacturing a silicon carbide semiconductor substrate according to claim 1 , wherein
the impurity concentration in the second silicon carbide semiconductor layer is not less than 1×10 14 cm −3 and not more than 7×10 15 cm −3 .

5. A method of manufacturing a silicon carbide semiconductor device, comprising steps of:
preparing a silicon carbide semiconductor substrate; and
processing the silicon carbide semiconductor substrate,
in the step of preparing a silicon carbide semiconductor substrate, the silicon carbide semiconductor substrate being manufactured with the method of manufacturing a silicon carbide semiconductor substrate according to claim 1 .

6. A method of manufacturing a silicon carbide semiconductor device, comprising steps of:
preparing a silicon carbide semiconductor substrate; and
processing the silicon carbide semiconductor substrate,
in the step of preparing a silicon carbide semiconductor substrate, the silicon carbide semiconductor substrate being manufactured with the method of manufacturing a silicon carbide semiconductor substrate according to claim 1 .

7. A method of manufacturing a silicon carbide semiconductor device,
comprising steps of:
preparing a silicon carbide semiconductor substrate; and
processing the silicon carbide semiconductor substrate,
in the step of preparing a silicon carbide semiconductor substrate, the silicon carbide semiconductor substrate being manufactured with the method of manufacturing a silicon carbide semiconductor substrate according to claim 2 .

8. A method of manufacturing a silicon carbide semiconductor device,
comprising steps of:
preparing a silicon carbide semiconductor substrate; and
processing the silicon carbide semiconductor substrate,
in the step of preparing a silicon carbide semiconductor substrate, the silicon carbide semiconductor substrate being manufactured with the method of manufacturing a silicon carbide semiconductor substrate according to claim 3 .

9. A method of manufacturing a silicon carbide semiconductor device,
comprising steps of:
preparing a silicon carbide semiconductor substrate; and
processing the silicon carbide semiconductor substrate,
in the step of preparing a silicon carbide semiconductor substrate, the silicon carbide semiconductor substrate being manufactured with the method of manufacturing a silicon carbide semiconductor substrate according to claim 4 .

Assignees

• Sumitomo Electric Industries

Inventors

• Genba Jun

Classifications

• H10P14/3442

  N-type · CPC title

• H10P14/3438

  Doping during depositing · CPC title

• H10P14/3208

  Silicon carbide · CPC title

• H10P14/2904

  Silicon carbide · CPC title

• H10P14/24

  using chemical vapour deposition [CVD] · CPC title