# US 2018/0323262 A1 · Silicon carbide single crystal substrate, silicon carbide epitaxial substrate, and method of manufacturing silicon carbide semiconductor device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2018/0323262 A1
- Document ID: US20180323262A1
- Status: Published application
- Kind: A1
- Application number: 15/772,183
- Filed: 2016-08-03
- Published: 2018-11-08
- Earliest claimed: 2015-11-24
- Assignees: Sumitomo Electric Industries, Ltd.
- Applicants: Sumitomo Electric Industries, Ltd.
- Inventors: Tsutomu Hori
- Web page: https://patentgrep.com/patent/US20180323262A1

## CPC

- H10D 62/8325: {Silicon carbide}
- C30B 25/186: {being specially pre-treated by, e.g. chemical or physical means}
- C30B 25/20: the substrate being of the same materials as the epitaxial layer
- C30B 29/00: Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B 29/36: Carbides
- H10D 12/031: {of IGBTs}
- H10D 30/0291: {of vertical DMOS [VDMOS] FETs}
- H10D 62/405: {Orientations of crystalline planes}
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/2904: {Silicon carbide}
- H10P 14/2926: {Crystal orientations}
- H10P 14/3408: {Silicon carbide}
- H10P 90/00: Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
- H10P 95/00: Generic processes or apparatus for manufacture or treatments not covered by the other groups of this subclass
- 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

A silicon carbide single crystal substrate includes a first main surface and an orientation flat. The orientation flat extends in a <11-20> direction. The first main surface includes an end region extending by at most 5 mm from an outer periphery of the first main surface. In a direction perpendicular to the first main surface, an amount of warpage of the end region continuous to the orientation flat is not greater than 3 μm.

## Claims

### Claim 1

A silicon carbide single crystal substrate comprising:
a first main surface; and
an orientation flat extending in a <11-20> direction,
the first main surface including an end region extending by at most 5 mm from an outer periphery of the first main surface, and
in a direction perpendicular to the first main surface, an amount of warpage of the end region continuous to the orientation flat being not greater than 3 μm.

### Claim 2 (depends on 1)

The silicon carbide single crystal substrate according to claim 1, wherein
when a cross-section which divides the orientation flat perpendicularly into two equal sections when viewed in the direction perpendicular to the first main surface is viewed, toward the orientation flat, the end region is warped upward in a direction away from a surface opposite to the first main surface, and
the amount of warpage represents a distance between a point of contact between the orientation flat and the first main surface and a point where a least square line calculated from a cross-sectional profile of the first main surface in a region extending from a position distant by 3 mm from the orientation flat toward a center of the first main surface to a position distant by 5 mm from the orientation flat intersects with the orientation flat.

### Claim 3 (depends on 1)

The silicon carbide single crystal substrate according to claim 1, wherein
when a cross-section which divides the orientation flat perpendicularly into two equal sections when viewed in the direction perpendicular to the first main surface is viewed, toward the orientation flat, the end region is warped downward in a direction toward a surface opposite to the first main surface, and
the amount of warpage represents a distance between a point of contact between the orientation flat and the first main surface and a point where a least square line calculated from a cross-sectional profile of the first main surface in a region extending from a position distant by 3 mm from the orientation flat toward a center of the first main surface to a position distant by 5 mm from the orientation flat intersects with a virtual plane extending along the orientation flat.

### Claim 4 (depends on 1)

The silicon carbide single crystal substrate according to claim 1, wherein
the amount of warpage is not greater than 2 μm.

### Claim 5 (depends on 4)

The silicon carbide single crystal substrate according to claim 4, wherein
the amount of warpage is not greater than 1 μm.

### Claim 6 (depends on 1)

A silicon carbide epitaxial substrate comprising:
the silicon carbide single crystal substrate according to claim 1; and
a silicon carbide layer on the first main surface,
the silicon carbide layer including a second main surface opposite to a surface in contact with the first main surface, and
the second main surface being free from a stacking fault extending in a <1-100> direction from the orientation flat and having a length not shorter than 1 mm.

### Claim 7 (depends on 1)

The silicon carbide single crystal substrate according to claim 1, wherein
when a line segment which divides the orientation flat perpendicularly into two equal sections is divided into four equal sections when viewed in the direction perpendicular to the first main surface, the first main surface includes a lower region extending from the orientation flat to a position corresponding to ¼ of the line segment, and
the amount of warpage of the end region continuous to an end portion of the lower region is not greater than 3 μm.

### Claim 8 (depends on 7)

A silicon carbide epitaxial substrate comprising:
the silicon carbide single crystal substrate according to claim 7; and
a silicon carbide layer on the first main surface,
the silicon carbide layer including a second main surface opposite to a surface in contact with the first main surface, and
the second main surface being free from a stacking fault extending in a <1-100> direction from the end portion of the lower region and having a length not shorter than 1 mm.

### Claim 9 (depends on 1)

The silicon carbide single crystal substrate according to claim 1, wherein
when a line segment which divides the orientation flat perpendicularly into two equal sections is divided into four equal sections when viewed in the direction perpendicular to the first main surface, the first main surface includes an upper region extending from an end portion opposite to the orientation flat to a position corresponding to ¼ of the line segment, and
the amount of warpage of the end region continuous to the end portion of the upper region is not greater than 3 μm.

### Claim 10 (depends on 9)

A silicon carbide epitaxial substrate comprising:
the silicon carbide single crystal substrate according to claim 9; and
a silicon carbide layer on the first main surface,
the silicon carbide layer including a second main surface opposite to a surface in contact with the first main surface, and
the second main surface being free from a stacking fault extending in a <1-100> direction from the end portion of the upper region and having a length not shorter than 1 mm.

### Claim 11 (depends on 1)

The silicon carbide single crystal substrate according to claim 1, wherein
when a line segment which divides the orientation flat perpendicularly into two equal sections is divided into four equal sections when viewed in the direction perpendicular to the first main surface, the first main surface includes a lower region extending from the orientation flat to a position corresponding to ¼ of the line segment and an upper region extending from an end portion opposite to the orientation flat to a position corresponding to ¼ of the line segment, and
the amount of warpage of the end region continuous to an end portion of the lower region is not greater than 3 μm and the amount of warpage of the end region continuous to the end portion of the upper region is not greater than 3 μm.

### Claim 12 (depends on 11)

A silicon carbide epitaxial substrate comprising:
the silicon carbide single crystal substrate according to claim 11; and
a silicon carbide layer on the first main surface,
the silicon carbide layer including a second main surface opposite to a surface in contact with the first main surface, and
the second main surface being free from a stacking fault extending in a <1-100> direction from the end portion of the lower region and having a length not shorter than 1 mm and from a stacking fault extending in the <1-100> direction from the end portion of the upper region and having a length not shorter than 1 mm.

### Claim 13 (depends on 6)

A method of manufacturing a silicon carbide semiconductor device comprising:
preparing the silicon carbide epitaxial substrate according to claim 6; and
processing the silicon carbide epitaxial substrate.