# US 2025/0146174 A1 · SiC EPITAXIAL WAFER

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- Number: US 2025/0146174 A1
- Document ID: US20250146174A1
- Status: Published application
- Kind: A1
- Application number: 18/938,549
- Filed: 2024-11-06
- Published: 2025-05-08
- Earliest claimed: 2023-11-07
- Assignees: Resonac Corporation
- Applicants: Resonac Corporation
- Inventors: Yoshikazu UMETA
- Web page: https://patentgrep.com/patent/US20250146174A1

## CPC

- C30B 25/20: the substrate being of the same materials as the epitaxial layer
- B32B 3/00: Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
- C30B 23/02: Epitaxial-layer growth
- C30B 29/36: Carbides
- 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
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM

## Abstract

An objective of the present invention is to provide a SiC epitaxial wafer with a large diameter, a thin thickness, and few triangular defects. A SiC epitaxial wafer includes a SiC substrate and a SiC epitaxial layer. The SiC substrate has a diameter of 195 mm or more and a thickness of 460 μm or less. The SiC epitaxial layer has a triangular defect density of 0.2 pieces/cm2 or less.

## Claims

### Claim 1

A SiC epitaxial wafer comprising:
a SiC substrate; and
a SiC epitaxial layer,
wherein the SiC substrate has a diameter of 195 mm or more and a thickness of 460 μm or less, and
wherein the SiC epitaxial layer has a triangular defect density of 0.2 pieces/cm2 or less.

### Claim 2 (depends on 1)

The SiC epitaxial wafer according to claim 1, wherein a local thickness variation (LTV) in each of a plurality of unit exposure regions classified as 20 mm squares is 4 μm or less in a planar view in a stacking direction of the SiC epitaxial wafer.

### Claim 3 (depends on 1)

The SiC epitaxial wafer according to claim 1, wherein site flatness (site flatness, front reference surface, least-squares best-fit reference plane, range (SFQR)) in each of a plurality of unit exposure regions classified as 20 mm squares is 2 μm or less in a planar view in a stacking direction of the SiC epitaxial wafer.

### Claim 4 (depends on 1)

The SiC epitaxial wafer according to claim 1, wherein warp is 90 μm or less.

### Claim 5 (depends on 1)

The SiC epitaxial wafer according to claim 1, wherein bow is 60 μm or less when a surface connecting a support point overlapping a circumference within 7.5 mm from an outermost circumference and an overlapping portion as seen in a thickness direction is used as a reference surface.

### Claim 6 (depends on 1)

The SiC epitaxial wafer according to claim 1, wherein SORI is 60 μm or less.

### Claim 7 (depends on 1)

The SiC epitaxial wafer according to claim 1,
wherein the SiC epitaxial layer can be divided into a plurality of regions each having a 5 mm square in a planar view in a stacking direction of the SiC epitaxial wafer, and
wherein a proportion of regions not having any triangular defect among the plurality of regions is 98% or more.

### Claim 8 (depends on 1)

The SiC epitaxial wafer according to claim 1, wherein the SiC epitaxial layer has a carrier concentration variation of 20% or less.

### Claim 9 (depends on 1)

The SiC epitaxial wafer according to claim 1, wherein a variation in a film thickness of the SiC epitaxial layer is 5% or less.