Dislocation movement in GaN films

We demonstrate that significant dislocation movement occurs below the surface of heteroepitaxial c-plane GaN films during their growth by metalorganic vapor phase epitaxy. Dislocations move primarily by vacancy-assisted climb, which appears to be driven by the high in-plane biaxial stresses present during growth. Annealing low dislocation density (4.3 x 10(8) cm(-2)) GaN films promotes dislocation climb and thus reduces both dislocation densities and in-plane stresses (at high temperatures), independent of epilayer growth conditions. (C) 2010 American Institute of Physics. [doi:10.1063/1.3532965]