# US 11,111,599 B2 · Single crystal growth method which includes covering a part of a surface of a raw material for sublimation with a metal carbide powder

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- Number: US 11,111,599 B2
- Document ID: US11111599B2
- Status: Granted
- Kind: B2
- Application number: 16/559,875
- Filed: 2019-09-04
- Published: 2020-03-12
- Granted: 2021-09-07
- Earliest claimed: 2018-09-06
- Assignees: Showa Denko K.K.
- Applicants: Showa Denko K.K.
- Inventors: Yohei Fujikawa
- Web page: https://patentgrep.com/patent/US11111599B2

## CPC

- C30B 23/066: {Heating of the material to be evaporated}
- C30B 23/00: Single-crystal growth by condensing evaporated or sublimed materials
- C30B 23/002: {Controlling or regulating}
- C30B 23/005: {Controlling or regulating flux or flow of depositing species or vapour}
- C30B 29/36: Carbides
- C30B 29/60: characterised by shape
- 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

## Abstract

The present invention provides a single crystal growth method capable of suppressing the recrystallization of the raw material gas subjected to sublimation on the surface of the raw material, and suppressing the generation of different polytypes in the crystal growing single crystal. The single crystal growth method is carried out in a crucible comprising an inner bottom for providing a raw material and a crystal mounting part facing the inner bottom. The method comprises in the following order: providing the raw material in the inner bottom; covering at least a part of a surface of the raw material with a metal carbide powder in a plan view from the crystal mounting part; and growing a single crystal disposed in the crystal mounting part by sublimating the raw material by heating.

## Claims

### Claim 1

A single crystal growth method, which is carried out in a crucible comprising an inner bottom for providing a raw material and a crystal mounting part facing the inner bottom,
the method comprising in the following order:
providing the raw material in the inner bottom;
covering a part but not the entire surface of the raw material with a metal carbide powder in a plan view from the crystal mounting part; and
growing a single crystal disposed in the crystal mounting part by sublimating the raw material by heating,
wherein in the covering step, an area covered with the metal carbide powder includes a central area of the surface of the raw material, and
the central area is an area of 20 area % of the total surface area in plan view at a top surface of the raw material from a center of the surface of the raw material.

### Claim 2 (depends on 1)

The single crystal growth method of claim 1,
wherein a particle diameter of the metal carbide powder is 0.1 mm or more and 2.0 mm or less.

### Claim 3 (depends on 1)

The single crystal growth method of claim 1,
wherein the metal carbide powder is a tantalum carbide powder.

### Claim 4 (depends on 1)

The single crystal growth method according to claim 1,
wherein an average thickness of a covered area made of the metal carbide powder in the covering step is 1.0 mm or more and 30 mm or less.

### Claim 5 (depends on 1)

The single crystal growth method of claim 1,
wherein the temperature of the central area is lower than that of a peripheral area.

### Claim 6 (depends on 1)

The single crystal growth method of claim 1,
wherein a temperature of the central area is at least 15° C. lower than a maximum temperature in the surface of the raw material.

### Claim 7 (depends on 1)

The single crystal growth method of claim 1,
wherein a partition plate is used to divide the area to be covered.

### Claim 8 (depends on 1)

The single crystal growth method of claim 1,
wherein a surface of the metal carbide powder is in a range within 20 mm from the raw material surface.