It was demonstrated that significant dislocation movement occurred below the surface of hetero-epitaxial c-plane GaN films during their growth by metalorganic vapour phase epitaxy. Dislocations moved primarily by vacancy-assisted climb, which appeared to be driven by the high in-plane biaxial stresses present during growth. Annealing low dislocation density (4.3 x 108/cm2) GaN films promotes dislocation climb and thus reduced both dislocation densities and in-plane stresses (at high temperatures), independent of epilayer growth conditions.

Dislocation Movement in GaN Films. M.A.Moram, T.C.Sadler, M.Häberlen, M.J.Kappers, C.J.Humphreys: Applied Physics Letters, 2010, 97[26], 261907