Group III nitride bulk crystals and their fabrication method
AssigneesSixPoint Materials, Inc., Seoul Semiconductor Co., Ltd.
InventorsTadao Hashimoto, Edward Letts
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Abstract
In one instance, the invention provides a bulk crystal of group III nitride having a thickness of more than 1 mm without cracking above the sides of a seed crystal. This bulk group III nitride crystal is expressed as Gax1Aly1In1-x1-y1N (0≦x1≦1, 0≦x1+y1≦1) and the seed crystal is expressed as Gax2Aly2In1-x2-y2N (0≦x2≦1, 0≦x2+y2≦1). The bulk crystal of group III nitride can be grown in supercritical ammonia or a melt of group III metal using at least one seed crystal having basal planes of c-orientation and sidewalls of m-orientation. By exposing only c-planes and m-planes in this instance, cracks originating from the sides of the seed crystal are avoided.
Claims20
A bulk crystal of group III nitride having a composition of Gax1Aly1In1-x1-y1N (0≦x1≦1, 0≦x1+y1≦1) and containing a seed crystal having a composition of Gax2Aly2In1-x2-y2N (0≦x2≦1, 0≦x2+y2≦1), wherein the bulk crystal has a thickness greater than 1 mm and the bulk crystal has fewer cracks within the bulk crystal above the seed crystal's edge than a comparative bulk crystal grown under otherwise identical conditions but grown using a square seed having the same surface area as said seed crystal but having m-plane and a-plane walls.
A bulk crystal of Gax1Aly1In1-x1-y1N (0≦x1≦1, 0≦x1+y1≦1) comprising
- (a) a seed crystal composed of Gax2Aly2In1-x2-y2N (0≦x2≦1, 0≦x2+y2≦1), the seed crystal having a first basal face, a second basal face opposite the first basal face, and a plurality of edge faces extending between the first basal face and the second basal face, said plurality of edge faces extending completely around a perimeter of the first basal face and the second basal face;
- (b) a first layer of Gax1Aly1In1-x1-y1N (0≦x1≦1, 0≦x1+y1≦1) on the first basal face of said seed crystal
- (c) a second layer of Gax1Aly1In1-x1-y1N (0≦x1≦1, 0≦x1+y1≦1) on said edge faces of the seed crystal, said second layer having a minimum thickness and a maximum thickness
- (d) and wherein the first layer has a thickness of at least five times the maximum thickness of said second layer.
A bulk crystal of single-crystal Gax1Aly1In1-x1-y1N (0≦x1≦1, 0≦x1+y1≦1) having a seed crystal as a portion of the bulk crystal, wherein the bulk crystal has a thickness greater than 1 mm, and the bulk crystal has no cracks within the bulk crystal above an edge of the seed crystal.
Dependencies are inferred from the claim text.