METHODS FOR PRODUCING IMPROVED CRYSTALLINTY GROUP III-NITRIDE CRYSTALS FROM INITIAL GROUP III-NITRIDE SEED BY AMMONOTHERMAL GROWTH

摘要

The present invention discloses methods to create higher quality group III-nitride wafers that then generate improvements in the crystalline properties of ingots produced by ammonothermal growth from an initial defective seed. By obtaining future seeds from carefully chosen regions of an ingot produced on a bowed seed crystal, future ingot crystalline properties can be improved. Specifically the future seeds are optimized if chosen from an area of relieved stress, on a cracked ingot or from a carefully chosen N-polar compressed area. When the seeds are sliced out, miscut of 3-10° helps to itnprove structural quality of successive growth. Additionally a method is proposed to improve crystal quality by using the ammonothermal method to produce a series of ingots, each using a specifically oriented seed from the previous ingot. When employed, these methods enhance the quality of Group III nitride wafers and thus improve the efficiency of any subsequent device.