Dislocation movement in GaN films

Abstract

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× 108cm-2) GaN films promotes dislocation climb and thus reduces both dislocation densities and in-plane stresses (at high temperatures), independent of epilayer growth conditions. © 2010 American Institute of Physics.