Process for large-scale ammonothermal manufacturing of gallium nitride boules
View Patent ↗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.
1. A method for growth of a wurtzite crystallographic structure gallium-containing nitride bulk crystal, the method comprising:
providing at least one gallium-containing nitride seed characterized by a wurtzite crystallographic structure, wherein,
the at least one seed comprises a first growth surface facing in a first direction;
a second growth surface facing in a second direction;
the second direction is opposite the first direction;
the first growth surface and the second growth surface have a substantially equivalent crystallographic orientation; and
the crystallographic orientation is within five degrees of a crystallographic plane selected from the (0 0 0 1) Ga-polar c-plane, the (0 0 0 −1) N-polar c-plane, and a semi-polar plane;
mounting the at least one gallium-containing nitride seed in an ammonothermal processing chamber; and
growing a crystalline gallium-containing nitride material from the supercritical solution on the first growth surface and on the second growth surface of the at least one seed to form a wurtzite crystallographic structure gallium-containing nitride bulk crystal.
2. The method of claim 1 , comprising increasing a thickness of the seed by at least 1 millimeter.
3. The method of claim 1 , comprising increasing a thickness of the seed by at least 2 millimeters.
4. The method of claim 1 , wherein the first growth surface and the second growth surface have a crystallographic orientation within five degrees of the (0 0 0 1) Ga-polar c-plane.
5. The method of claim 1 , wherein the first growth surface and the second growth surface have a crystallographic orientation within five degrees of the (0 0 0 −1) N-polar c-plane.
6. The method of claim 1 , wherein the first growth surface and the second growth surface have a crystallographic orientation within five degrees of the {1 −1 0 +1} semi-polar plane.
7. The method of claim 1 , wherein the first growth surface and the second growth surface have a crystallographic orientation within five degrees of the {1 −1 0 −1} semi-polar plane.
8. The method of claim 1 , wherein the first growth surface and the second growth surface have a minimum lateral dimension of three centimeters.
9. The method of claim 1 , wherein the seed comprises a bi-crystal.
10. A method for growth of a wurtzite crystallographic structure gallium-containing nitride bulk crystal, the method comprising:
providing a gallium-containing nitride seed, wherein the seed comprises a first gallium-containing nitride seed plate and a second gallium-containing nitride seed plate, wherein,
the first gallium-containing nitride seed plate comprises a first surface, a second surface, and a thickness separating the first surface and the second surface, wherein the first surface is opposite the second surface;
the second gallium-containing nitride seed plate comprises a first surface, a second surface, and a thickness separating the first surface and the second surface;
the second surface of the first seed plate faces and is proximate the second surface of the second seed plate;
the first surface of the first seed plate faces in an opposite direction to the first surface of the second seed plate;
the first surface of the first seed plate and the first surface of the second seed plate have an equivalent crystallographic orientation; and
the crystallographic orientation is within five degrees of a crystallographic plane selected from the (0 0 0 1) Ga-polar c-plane, the (0 0 0 −1) N-polar c-plane, and a semi-polar plane;
mounting the at least one gallium-containing nitride seed in an ammonothermal processing chamber; and
growing crystalline gallium-containing nitride material from the supercritical solution on the first surface of the first seed plate and on the first surface of the second seed plate to provide a wurtzite crystallographic structure gallium-containing nitride bulk crystal.
11. The method of claim 10 , wherein,
the first surface of the first seed plate and the first surface of the second seed plate have a crystallographic orientation to within 5 degrees of the (0 0 0 1) Ga-polar c-plane.
12. The method of claim 10 , wherein,
the first surface of the first seed plate and the first surface of the second seed plate have a crystallographic orientation to within 5 degrees of the (0 0 0 −1) N-polar c-plane.
13. The method of claim 10 , wherein,
the first surface of the first seed plate and the first surface of the second seed plate have a crystallographic orientation to within 5 degrees of the semi-polar {1 −1 0 −1} orientation.
14. The method of claim 10 , wherein,
the first surface of the first seed plate and the first surface of the second seed plate have a crystallographic orientation to within 5 degrees of the semi-polar {1 −1 0 +1} orientation.
15. The method of claim 10 , wherein the second surface of the first seed plate and the second surface of the second seed plate are separated by less than 1 millimeter.
16. The method of claim 10 , wherein the second surface of the first seed plate and the second surface of the second seed plate are in direct contact.