Patent ID: 9650723
Date: 2017-05-16
CPC Classifications: C30B,H01L

Claim:
1. A method for forming a free-standing ammonothermal group III metal nitride crystal, comprising: providing a non-gallium-nitride substrate having a coefficient of thermal expansion approximately equal to that of gallium nitride, with a value in a range of 4-8×10 providing a crystalline gallium-containing nitride layer overlying the substrate; depositing a diffusion barrier layer and an inert layer overlying at least some side surfaces of the substrate and the diffusion barrier layer, the diffusion barrier layer comprising at least one of W, TiW, Ta, Mo, and Re, and the inert layer comprising at least one of Au, Ag, Pt, Pd, Rh, Ru, Ir, Re, Ni, Cr, V, Ti, and Ta; placing the substrate, a group III metal source, at least one mineralizer composition, and a nitrogen containing solvent within a sealable container; and forming an ammonothermal group III metal nitride crystal on the crystalline gallium-containing nitride layer by heating the sealable container to a temperature of at least about 400 degrees Celsius.