METHOD OF GROWING GROUP III NITRIDE CRYSTALS
First Claim
1. A group III nitride seed having a first uncracked surface and a second uncracked surface comprising a first layer of group III nitride wafers, the first layer having a first face and a second face, and a second layer of group III nitride wafers, the second layer having a first face and a second face, the first face of the first layer facing the first face of the second layer, the second face of the first layer having at least one crack, and overlying the second face of the first layer a sufficient thickness of group III nitride to provide said first uncracked surface.
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Abstract
The present invention provides a method of growing an ingot of group III nitride. Group III nitride crystals such as GaN are grown by the ammonothermal method on both sides of a seed to form an ingot and the ingot is sliced into wafers. The wafer including the first-generation seed is sliced thicker than the other wafers so that the wafer including the first-generation seed does not break. The wafer including the first-generation seed crystal can be used as a seed for the next ammonothermal growth.
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Citations
20 Claims
- 1. A group III nitride seed having a first uncracked surface and a second uncracked surface comprising a first layer of group III nitride wafers, the first layer having a first face and a second face, and a second layer of group III nitride wafers, the second layer having a first face and a second face, the first face of the first layer facing the first face of the second layer, the second face of the first layer having at least one crack, and overlying the second face of the first layer a sufficient thickness of group III nitride to provide said first uncracked surface.
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6. A group III nitride seed composed of two or more wafers contacting one another along a face rather than along an edge of the wafers, and wherein at least one of the wafers is (a) a wafer having a surface crack, or (b) a cracked wafer formed using HVPE and therefore having a value of density of line defects (e.g. dislocations) and grain boundaries greater than 105 cm−
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wherein the first and second wafers are positioned so that said the first wafer is offset from the second wafer so that an edge of the first wafer does not align with an edge of the second wafer. - View Dependent Claims (7)
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- 8. A group III nitride ingot comprising a first group III nitride layer upon a first seed and a second seed and a second group III nitride layer upon a third seed and a fourth seed, wherein an edge of the first seed is not aligned with a corresponding edge of any seed in the second layer.
- 10. A seed composed of a first group III nitride wafer secured to a second group III nitride wafer, wherein the first wafer has a crack propagating from a first face to a second face of the first wafer, wherein the second wafer has a crack propagating from a first face to a second face of the second wafer, and wherein the seed has a regular shape from which an ingot may be formed.
Specification