# US 11,078,598 B2 · Method for producing silicon carbide single crystal

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- Number: US 11,078,598 B2
- Document ID: US11078598B2
- Status: Granted
- Kind: B2
- Application number: 16/468,413
- Filed: 2017-12-15
- Published: 2019-10-03
- Granted: 2021-08-03
- Earliest claimed: 2016-12-26
- Assignees: Showa Denko K.K.
- Applicants: Showa Denko K.K.
- Inventors: Yohei Fujikawa; Hidetaka Takaba
- Web page: https://patentgrep.com/patent/US11078598B2

## CPC

- C30B 29/36: Carbides
- C30B 23/005: {Controlling or regulating flux or flow of depositing species or vapour}
- C30B 23/06: Heating of the deposition chamber, the substrate or the materials to be evaporated
- 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

A silicon carbide single crystal is grown by a method comprising: a single crystal growth step of growing a silicon carbide single crystal so as to not close a gap between a side surface of the silicon carbide single crystal growing on a silicon carbide seed crystal, and an inner-side surface of a guide member and a crystal deposited on the inner-side surface of the guide member; a crystal growth termination step of terminating crystal growth by temperature lowering; and a gap enlargement step, performed between the single crystal growth step and the crystal growth termination step, of enlarging the gap by maintaining a difference, Pin−Pout, between partial pressure Pin of Si2C in a source gas in the vicinity of an inlet of the gap and partial pressure Pout of Si2C in a source gas in the vicinity of an outlet of the gap at 0.18 torr or less.

## Claims

### Claim 1

A method for producing a silicon carbide single crystal in which a single crystal of silicon carbide is grown on a silicon carbide seed crystal placed inside a crucible by using a guide member to guide a source gas to the silicon carbide seed crystal side, wherein the guide member has one end positioned in the vicinity of the silicon carbide seed crystal, and the method comprising:
a single crystal growth step of growing a silicon carbide single crystal in a manner so as to not completely close a gap between a side surface of the silicon carbide single crystal growing on the silicon carbide seed crystal, and an inner-side surface of the guide member and a crystal deposited on the inner-side surface of the guide member;
a crystal growth termination step of terminating crystal growth by lowering a temperature;
and a gap enlargement step, performed between the single crystal growth step and the crystal growth termination step, of enlarging the gap by maintaining a difference, Pin−Pout, between a partial pressure Pin of Si2C in a source gas in the vicinity of an inlet of the gap and a partial pressure Pout of Si2C in a source gas in the vicinity of an outlet of the gap, at 0.18 torr or less.

### Claim 2 (depends on 1)

The method for producing a silicon carbide single crystal according to claim 1, wherein the gap enlargement step is performed for at least 5 hours.

### Claim 3 (depends on 1)

The method for producing a silicon carbide single crystal according to claim 1, wherein the gap enlargement step is performed for a period of at least 5% of a time required for the total crystal growth.

### Claim 4 (depends on 1)

The method for producing a silicon carbide single crystal according to claim 1, wherein a silicon carbide single crystal having a length of at least 15 mm is produced.

### Claim 5 (depends on 1)

The method for producing a silicon carbide single crystal according to claim 1, wherein a silicon carbide single crystal is produced at an average growth rate of at least 0.15 mm/h.

### Claim 6 (depends on 1)

The method for producing a silicon carbide single crystal according to claim 1, wherein a temperature difference between the temperature of a source gas in the vicinity of an inlet of the gap and the temperature in the vicinity of an outlet of the gap during the gap enlargement step is smaller than the temperature difference between the temperature of a source gas in the vicinity of an inlet of the gap and the temperature in the vicinity of an outlet of the gap during the single crystal growth step.