Strain relaxation of GaN nucleation layers during rapid thermal annealing

摘要

The strain relaxation of GaN nucleation layers grown on sapphire (0001) during rapid thermal annealing was studied in a synchrotron x-ray scattering experiment. The as-grown GaN nucleation layer is compressively strained. Upon annealing to 750℃, the lattice strain first changes to tensile. This tensile strain is released progressively as the annealing temperature increases. The nucleation layer sublimates significantly at 1050℃ where it becomes mostly strain-free hexagonal GaN.