An investigation was made of the influence of AlGaN buffer growth temperature on strain status and crystal quality of the GaN film on Si(111) substrates by metal organic chemical vapour deposition. It was demonstrated by the optical microscopy that AlGaN buffer growth temperature had a remarkable effect on compensating tensile stress in top GaN layer and preventing the formation of cracks. X-ray diffraction and atomic force microscopy analysis showed crystal quality and surface morphology of the GaN epilayer could be improved through increasing AlGaN buffer growth temperature. 1μm crack-free GaN epilayer on Si (111) substrates was obtained with graded AlGaN buffer layer at optimized temperature of 1050C. Transmission electron microscopy analysis revealed that a significant reduction in threading dislocations was achieved in GaN epilayer.

Influence of AlGaN Buffer Growth Temperature on GaN Epilayer based on Si(111) Substrate. M.Wei, X.Wang, X.Pan, H.Xiao, C.Wang, M.Zhang, Z.Wang: Journal of Physics - Conference Series, 2011, 276[1], 012094