On cracking in thick GaN layers grown on sapphire substrates
M.G. Mynbaeva, A.A. Sitnikova, A.N. Smirnov, K.D. Mynbaev, H. Lipsanen, A.V. Kremleva, D.A. Bauman, V.E. Bougrov & A.E. Romanov
Self-organization mechanisms promoting elimination of cracks in thick GaN layers
grown on sapphire substrates are considered on the basis of the experimental results on the
fabrication of the layers by Hydride Vapor-Phase Epitaxy on MOCVD-grown GaN/Al2O3
templates. The obtained data support the supposition on the closure of tensile stress-related
cracks via diffusion processes and demonstrate the strong contribution of bulk diffusion in
addition to surface diffusion discussed earlier.