PROCESS FOR LARGE-SCALE AMMONOTHERMAL MANUFACTURING OF GALLIUM NITRIDE BOULES

• US 20100031875A1
• Filed: 08/03/2009
• Published: 02/11/2010
• Est. Priority Date: 08/07/2008
• Status: Active Grant

• Current Assignee: SL Technology Incorporated (Reliv' International, Inc.)
• Original Assignee: Soraa, Inc.
• Inventors: D'EVELYN, MARK P.
• Granted Patent: US 8,979,999 B2
• Time in Patent Office: Days
• US Class Current: 117/71
• CPC Class Codes: B01J 2203/0665 Gallium nitrides
• CPC Class Codes: B01J 2203/068 Crystal growth
• CPC Class Codes: B01J 3/008 Processes carried out under supercritical conditions
• CPC Class Codes: B01J 3/042 in the form of a tube
• CPC Class Codes: B01J 3/065 Presses for the formation of diamonds or boronitrides
• CPC Class Codes: B30B 11/002 Isostatic press chambers; Press stands therefor
• CPC Class Codes: C30B 29/406 Gallium nitride
• CPC Class Codes: C30B 7/10 by application of pressure, e.g. hydrothermal processes

Abstract

A method for large-scale manufacturing of gallium nitride boules. Large-area single crystal seed plates are suspended in a rack, placed in a large diameter autoclave or internally-heated high pressure apparatus along with ammonia and a mineralizer, and grown ammonothermally. The seed orientation and mounting geometry are chosen to provide efficient utilization of the seed plates and of the volume inside the autoclave or high pressure apparatus. The method is scalable up to very large volumes and is cost effective.

Claims

1. A method for growth of a gallium-containing nitride crystal, the method comprising:

providing gallium-containing source material;

providing a mineralizer;

providing at least two seed plates, including a first seed plate and a second seed plate;

supporting the first seed plate and the second seed plate in a first site and a second site of a seed rack, the first seed plate and the second seed plate having substantially an equivalent crystallographic orientation to within five degrees, each of the first seed plate and the second seed plate having a length of at least 1 centimeter;

placing the source material, mineralizer, and seed plates in a sealable container;

introducing a nitrogen containing solvent into the sealable container;

processing the source material, mineralizer, and seed plates contained in the sealable container in a supercritical fluid at a temperature higher than about 400 degrees Celsius and a pressure higher than about 2 kbar.

2. The method of claim 1 wherein each of the first seed plate and the second seed plate comprise a first side and second side, the first side and the second side having the equivalent crystallographic orientation to within five degrees.

3. The method of claim 1 wherein either the first seed plate or the second seed plate is characterized by a maximum lateral dimension of at least two centimeters and a minimum lateral dimension of at least one centimeter.

4. The method of claim 1 further comprising increasing the thickness of at least one of the seed plates by at least 1 millimeter.

5. The method of claim 4 wherein the thickness of at least one of the seed plates is increased by at least 2 millimeters.

6. The method of claim 1 wherein at least one of the surfaces of at least one of the seed plates has a crystallographic orientation within five degrees of the {1 −

1 0 0} m-plane.

7. The method of claim 6 wherein the seed plate has a substantially rectangular shape.

8. The method of claim 1 wherein at least one of the surfaces of at least one of the seed plates has a crystallographic orientation within five degrees of the {1 −

1 0 ±

1} semi-polar plane.

9. The method of claim 8 wherein the seed plate has a substantially rectangular shape.

10. The method of claim 1 wherein the large-area surfaces of the seed plates have a crystallographic orientation within five degrees of the (0 0 0 1) Ga-polar c-plane.

11. The method of claim 1 wherein the large-area surfaces of the seed plates have a crystallographic orientation within five degrees of the (0 0 0 −

1) N-polar c-plane.

12. The method of claim 1 further comprising slicing a boule derived from either the first seed plate or the second seed plate to prepare at least one of m-plane, a-plane, c-plane, or semi-polar substrates.

13. A method for growth a gallium-containing nitride crystal comprising:

providing gallium-containing source material;

providing a mineralizer;

providing at least a first seed plate and a second seed plate, the first seed plate having a first side having a first crystallographic orientation and a second side having a second crystallographic orientation, the second seed plate having a first side having a first crystallographic orientation and a second side having a second crystallographic orientation,

wherein the second side of the first seed plate and the second side of the second seed plate have an equivalent crystallographic orientation to within five degrees and have a minimum lateral dimension of at least 1 centimeter;

supporting the first seed plate and the second seed plate such that the first side of the first seed crystal faces the first side of the second seed crystal and spaced by a predetermined gap between the first side of the first seed crystal and the first side of the second seed crystal;

placing the source material, mineralizer, and the seed plates in a sealable container;

introducing a nitrogen-containing solvent in the sealable container; and

processing the source material, mineralizer, and seed plates contained in the sealable container in a supercritical fluid at a temperature higher than about 400 degrees Celsius and a pressure higher than about 2 kbar.

14. The method of claim 13 wherein either the first side or the second side of respective first seed plate or second seed plate has a maximum lateral dimension of at least two centimeters and a minimum lateral dimension of at least one centimeter.

15. The method of claim 13 further comprising increasing a first thickness of the first seed plate and a second thickness of a second seed plate by at least 1 millimeter each.

16. The method of claim 13 further comprising increasing a first thickness of the first seed plate and a second thickness of a second seed plate by at least 2 millimeter each.

17. The method of claim 13 wherein each of the second sides, which is outward facing, has a crystallographic orientation within five degrees of the (0 0 0 1) Ga-polar c-plane.

18. The method of claim 13 wherein each of the second sides, which is outward facing, has a crystallographic orientation within five degrees of the (0 0 0 −

1) N-polar c-plane.

19. The method of claim 13 wherein each of the second sides, which is outward facing, has a crystallographic orientation within five degrees of the {1 −

1 0 −

1} semi-polar plane.

20. The method of claim 13 further comprising slicing a boule derived from either the first seed plate or the second seed plate to prepare at least one of m-plane, a-plane, c-plane, or semi-polar substrates.