# US 9,039,832 B2 · High pressure high temperature (HPHT) method for the production of single crystal diamonds

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- Number: US 9,039,832 B2
- Document ID: US9039832B2
- Status: Granted
- Kind: B2
- Application number: 13/144,512
- Filed: 2010-01-15
- Published: 2011-11-10
- Granted: 2015-05-26
- Earliest claimed: 2009-01-16
- Assignees: Element Six Technologies Limited
- Applicants: Raymond Anthony Spits; Carlton Nigel Dodge
- Inventors: Raymond Anthony Spits; Carlton Nigel Dodge
- Web page: https://patentgrep.com/patent/US9039832B2

## CPC

- C30B 29/04: Diamond
- B01J 3/062: {characterised by the composition of the materials to be processed}
- B01J 23/745: Iron
- B01J 23/75: Cobalt
- B01J 23/755: Nickel
- B01J 2203/061: Graphite
- B01J 2203/062: Diamond
- B01J 2203/0655: Diamond
- B01J 2203/068: Crystal growth
- 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
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS

## Abstract

A high pressure high temperature (HPHT) method for synthesizing single crystal diamond, wherein a single crystal diamond seed having an aspect ratio of at least (1) and a growth surface substantially parallel to a {110} crystallographic plane is utilized is described. The growth is effected at a temperature in the range from 1280° C. to 1390° C.

## Claims

### Claim 1

A method for synthesizing single crystal diamond comprising:
(a) selecting a single crystal diamond seed having a growth surface with two orthogonal dimensions a* and b*, where a* is the longest dimension of the growth surface substantially aligned along a <100> or <110> direction in the plane of the growth surface, and b* is the longest dimension of the growth surface in a direction orthogonal to a* lying in the plane of the growth surface, where the aspect ratio of the growth surface which is defined as a*/b* is at least 1 and the growth surface is substantially parallel to a {110} crystallographic plane;
(b) mounting the seed on or into a surface of a substrate such that the growth surface of the seed is exposed and the growth surface of the seed is substantially parallel to the surface of the substrate; and
(c) effecting crystal growth in a high pressure high temperature environment at a temperature greater than 1280° C. under conditions such that a single crystal diamond is produced on at least the growth surface of the seed;
wherein the synthesized single crystal diamond has a longest dimension a# aligned along a <100> or <110> direction, which exceeds at least 2 mm.

### Claim 2 (depends on 1)

A method according to claim 1, wherein the edges of the growth surface of the single crystal diamond seed are within about 20° of either <100> or <110> directions or a mixture of <100> and <110> directions.

### Claim 3 (depends on 1)

A method according to claim 1, wherein in step (c), crystal growth is effected at a temperature in the range from 1280° C. to 1320° C.

### Claim 4 (depends on 1)

A method according to claim 1, wherein in step (c), crystal growth is effected at a temperature in the range from 1350° C. to 1390° C.

### Claim 5 (depends on 1)

A method according to claim 1, wherein the growth surface of the single crystal diamond seed has a dimension, a*, of at least 0.25 mm.

### Claim 6 (depends on 1)

A method according to claim 1, wherein the normal to the growth surface of the single crystal diamond seed lies within 20° of a <110> direction.

### Claim 7 (depends on 1)

A method according to claim 1, wherein in step (c), crystal growth is effected at a pressure in the range from 5 to 6 GPa.

### Claim 8 (depends on 1)

A method according to claim 1, wherein the diamond seed selected is such that at least about 30% of the area of the growth surface of the seed is a single growth sector.

### Claim 9 (depends on 1)

A method according to claim 1, wherein the diamond seed selected has a surface roughness, Ra, of less than about 100 nm.

### Claim 10 (depends on 1)

A method according to claim 1, wherein the diamond seed selected has a low level of strain, such that the birefringence over at least 50% of the area of the growth surface of the seed is less than 5×10−3.

### Claim 11 (depends on 1)

A method according to claim 1, wherein the aspect ratio of the growth surface of the single crystal diamond seed which is defined as a*/b* is less than 1.5.

### Claim 12 (depends on 1)

A method according to claim 1, wherein in step (c), crystal growth is effected in a temperature range from 1280° C. to 1390° C.