Self-organized propagation of dislocations in GaN films during epitaxial lateral overgrowth

Dislocation propagation and defect evolution in GaN films formed by epitaxi al lateral overgrowth (ELO) are examined by transmission electron microscop y. A novel effect that induces self-organized propagation of preexisting di slocations in ELO films is evaluated. This propagation forms dislocations i nto bundle structures along the stripes of masks used for ELO. The dislocat ion bundling gives rise to crystallographic tilting in the overgrown region on the mask and leads to a total reduction of threading dislocation densit y in the film. (C) 2000 American Institute of Physics. [S0003-6951(00)04504 -6].