# US 10,770,548 B2 · Silicon carbide semiconductor device and method of manufacturing silicon carbide semiconductor device

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- Number: US 10,770,548 B2
- Document ID: US10770548B2
- Status: Granted
- Kind: B2
- Application number: 16/277,419
- Filed: 2019-02-15
- Published: 2019-08-29
- Granted: 2020-09-08
- Earliest claimed: 2018-02-28
- Assignees: Fuji Electric Co., Ltd.
- Applicants: Fuji Electric Co., Ltd.
- Inventors: Tsuyoshi Araoka; Mitsuo Okamoto; Yohei Iwahashi
- Web page: https://patentgrep.com/patent/US10770548B2

## CPC

- H10D 62/8325: {Silicon carbide}
- H10D 1/66: Conductor-insulator-semiconductor capacitors, e.g. MOS capacitors
- H10D 8/051: {of Schottky diodes}
- H10P 14/2904: {Silicon carbide}
- H10P 14/6322: {Formation by thermal treatments (formation by plasma treatment H10P14/6319)}
- H10P 14/6336: {in the presence of a plasma [PECVD]}
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/6529: {by exposure to a gas or vapour}
- H10P 14/662: {Laminate layers, e.g. stacks of alternating high-k metal oxides (adhesion layers or buffer layers H10P14/6508, H10P14/6548)}
- H10P 14/6687: {the compound comprising silicon and nitrogen}
- H10P 14/69215: {the material being a silicon oxide, e.g. SiO2}
- H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A silicon nitride film having a thickness in a range from 1 [nm] to 3 [nm] is deposited on a front surface of a silicon carbide semiconductor base, by an ALD method. Next, on the silicon nitride film, for example, a silicon oxide film having a thickness in a range from 20 [nm] to 100 [nm] is deposited. After deposition of the silicon oxide film, for example, heat treatment is performed at a temperature in a range from 1100 degrees C. to 1350 degrees C., in a gas atmosphere that includes oxygen. By this heat treatment, nitrogen surface density of an interface of the silicon carbide semiconductor base and the silicon oxide film (gate insulating film) is increased, reducing interface state density of the interface of the silicon carbide semiconductor base and the silicon nitride film.

## Claims

### Claim 1

A silicon carbide semiconductor device, comprising:
a semiconductor base including silicon carbide; and
a gate insulating film provided on a surface of the semiconductor base, wherein
a nitrogen surface density at an interface of the semiconductor base and the gate insulating film is in a range of 6×1014/cm2 to 1.2×1015/cm2, wherein
a half width of a peak of a nitrogen profile in a thickness direction in a region including the interface of the semiconductor base and the gate insulating film, is in a range of 2 nm to 4 nm.

### Claim 2 (depends on 1)

The silicon carbide semiconductor device according to claim 1, wherein
hydrogen volume densities in the gate insulating film and at the interface of the semiconductor base and the gate insulating film are 1×1021/cm3 or less.

### Claim 3 (depends on 2)

The silicon carbide semiconductor device according to claim 2, wherein
the hydrogen volume densities in the gate insulating film and at the interface of the semiconductor base and the gate insulating film are 1×1020/cm3 or less.

### Claim 4 (depends on 1)

The silicon carbide semiconductor device according to claim 1, wherein
the surface of the semiconductor base, forming the interface with the gate insulating film, is in a (0001) plane, a (000-1) plane, a (1-100) plane, or a (11-20) plane.

### Claim 5

A method of manufacturing a silicon carbide semiconductor device, the method comprising:
forming on a front surface of a semiconductor base including silicon carbide, a silicon nitride film having a thickness in a range of lnm to 3 nm;
forming on the silicon nitride film, a gate insulating film; and
causing nitrogen atoms in the silicon nitride film to react with the semiconductor base by a heat treatment in an atmosphere that includes oxygen, after the forming of the gate insulating film.

### Claim 6 (depends on 5)

The method according to claim 5, wherein causing the nitrogen atoms to react with the semiconductor base includes performing the heat treatment at a temperature in a range of 1100 degrees C. to 1350 degrees C.

### Claim 7 (depends on 5)

The method according to claim 5, wherein the forming the silicon nitride film includes forming the silicon nitride film by a chemical vapor disposition method that includes an atomic layer deposition method.