# US 12,183,792 B2 · SiC composite substrate and composite substrate for semiconductor device

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- Number: US 12,183,792 B2
- Document ID: US12183792B2
- Status: Granted
- Kind: B2
- Application number: 17/445,617
- Filed: 2021-08-23
- Published: 2021-12-09
- Granted: 2024-12-31
- Earliest claimed: 2019-03-27
- Assignees: NGK Insulators, Ltd.
- Applicants: Ngk Insulators, Ltd.
- Inventors: Kiyoshi Matsushima; Jun Yoshikawa; Morimichi Watanabe; Risa Miyakaze
- Web page: https://patentgrep.com/patent/US12183792B2

## CPC

- H10D 62/8325: {Silicon carbide}
- C30B 25/02: Epitaxial-layer growth
- C30B 29/36: Carbides
- C30B 33/02: Heat treatment (C30B33/04, C30B33/06 take precedence)
- H10D 62/40: Crystalline structures
- H10P 14/20: of semiconductor materials
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/2904: {Silicon carbide}
- H10P 14/2925: {Surface structures}
- H10P 14/2926: {Crystal orientations}
- H10P 14/3408: {Silicon carbide}
- H10P 14/3456: {Polycrystalline}
- H10P 72/0418: {for etching}
- H10P 72/0424: {using mainly spraying means, e.g. nozzles}
- H10P 72/0431: {Apparatus for thermal treatment}
- H10P 72/0436: {mainly by radiation}
- H10P 90/00: Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
- H10P 14/3208: {Silicon carbide}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Provided is a SiC composite substrate including a biaxially-oriented SiC layer in which SiC is oriented in both a c-axis direction and an a-axis direction, and a SiC polycrystalline layer provided on one surface of the biaxially-oriented SiC layer. A joint interface of the biaxially-oriented SiC layer and the SiC polycrystalline layer has an uneven shape, which has an amount of unevenness of 1 to 200 μm.

## Claims

### Claim 1

A SiC composite substrate comprising:
a biaxially-oriented SiC layer in which SiC is oriented in both a c-axis direction and an a-axis direction; and
a SiC polycrystalline layer provided on one surface of the biaxially-oriented SiC layer,
wherein a warpage-free joint interface of the biaxially-oriented SiC layer and the SiC polycrystalline layer has an uneven shape, which has an amount of unevenness of 1 to 200 μm.

### Claim 2 (depends on 1)

The SiC composite substrate according to claim 1, wherein the amount of unevenness is 1 to 180 μm.

### Claim 3 (depends on 1)

The SiC composite substrate according to claim 1, wherein the amount of unevenness is 1 to 110 μm.

### Claim 4 (depends on 1)

The SiC composite substrate according to claim 1, wherein the warpage-free joint interface has pores, which have a pore diameter smaller than the amount of unevenness.

### Claim 5 (depends on 1)

The SiC composite substrate according to claim 1, wherein the biaxially-oriented SiC layer has a defect density of 1.0×101/cm2 or less.

### Claim 6 (depends on 1)

A composite substrate for a semiconductor device comprising:
the SiC composite substrate according to claim 1; and
a functional layer for a semiconductor device provided on the biaxially-oriented SiC layer of the SiC composite substrate.