# US 2021/0280677 A1 · SiC WAFER AND MANUFACTURING METHOD THEREOF

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- Number: US 2021/0280677 A1
- Document ID: US20210280677A1
- Status: Published application
- Kind: A1
- Application number: 17/183,549
- Filed: 2021-02-24
- Published: 2021-09-09
- Earliest claimed: 2020-03-05
- Assignees: Hitachi Metals, Ltd.
- Applicants: Hitachi Metals, Ltd.
- Inventors: Keisuke KOBAYASHI; Akio SHIMA
- Web page: https://patentgrep.com/patent/US20210280677A1

## CPC

- H10D 62/8325: {Silicon carbide}
- H10D 12/031: {of IGBTs}
- H10D 30/0291: {of vertical DMOS [VDMOS] FETs}
- H10D 30/66: Vertical DMOS [VDMOS] FETs
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/2904: {Silicon carbide}
- H10P 14/3208: {Silicon carbide}
- H10P 14/3408: {Silicon carbide}
- H10P 14/38: {characterised by treatments done after the formation of the materials}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A SiC wafer including a SiC substrate and an epitaxial layer formed on the SiC substrate and containing SiC is provided, and a composition ratio of C—Si of an upper surface of the epitaxial layer is 50 atm % or less.

## Claims

### Claim 1

A SiC wafer comprising:
a SiC substrate; and
an epitaxial layer formed on the SiC substrate and containing SiC,
wherein a composition ratio of C—Si of an upper surface of the epitaxial layer is 50 atm % or less.

### Claim 2 (depends on 1)

The SiC wafer according to claim 1,
wherein the composition ratio of C—Si of the upper surface of the epitaxial layer is larger than 10 atm %.

### Claim 3 (depends on 1)

The SiC wafer according to claim 1,
wherein a composition ratio of C—C of the upper surface of the epitaxial layer is 8.7 atm % or more.

### Claim 4 (depends on 1)

The SiC wafer according to claim 1,
wherein a composition ratio of C—C of the upper surface of the epitaxial layer is 35 atm % or more.

### Claim 5 (depends on 1)

The SiC wafer according to claim 1,
wherein a composition ratio of C—O of the upper surface of the epitaxial layer is 3.6 atm % or more.

### Claim 6 (depends on 1)

The SiC wafer according to claim 1,
wherein a composition ratio of C—O of the upper surface of the epitaxial layer is 10 atm % or more.

### Claim 7 (depends on 1)

The SiC wafer according to claim 1,
wherein a sum of composition ratios of bonds containing carbon other than C—Si is larger than the composition ratio of C—Si in the upper surface of the epitaxial layer.

### Claim 8

A SiC wafer comprising:
a SiC substrate; and
an epitaxial layer formed on the SiC substrate and containing SiC,
wherein a composition ratio of C—Si of an upper surface of the epitaxial layer is 83 atm % or less.

### Claim 9

A manufacturing method of a SiC wafer comprising:
(a) preparing a SiC substrate;
(b) forming an epitaxial layer containing SiC on the SiC substrate; and
(c) modifying a composition of an upper surface of the epitaxial layer, thereby setting a composition ratio of C—Si of the upper surface of the epitaxial layer to 50 atm % or less.

### Claim 10 (depends on 9)

The manufacturing method of the SiC wafer according to claim 9,
wherein, after the (c), the composition ratio of C—Si of the upper surface of the epitaxial layer is larger than 10 atm %.

### Claim 11 (depends on 9)

The manufacturing method of the SiC wafer according to claim 9,
wherein, after the (c), a composition ratio of C—C of the upper surface of the epitaxial layer is 8.7 atm % or more.

### Claim 12 (depends on 9)

The manufacturing method of the SiC wafer according to claim 9,
wherein, after the (c), a composition ratio of C—C of the upper surface of the epitaxial layer is 35 atm % or more.

### Claim 13 (depends on 9)

The manufacturing method of the SiC wafer according to claim 9,
wherein, after the (c), a composition ratio of C—O of the upper surface of the epitaxial layer is 3.6 atm % or more.

### Claim 14 (depends on 9)

The manufacturing method of the SiC wafer according to claim 9,
wherein, after the (c), a composition ratio of C—O of the upper surface of the epitaxial layer is 10 atm % or more.

### Claim 15 (depends on 9)

The manufacturing method of the SiC wafer according to claim 9,
wherein, after the (c), a sum of composition ratios of bonds containing carbon other than C—Si is larger than the composition ratio of C—Si in the upper surface of the epitaxial layer.