Interaction between dislocations and He-implantation-induced voids in GaN epitaxial layers

In this letter, we demonstrate that helium high-dose implantation is able to produce voids in GaN and we describe the behavior of material dislocations under these conditions. Two main types of nanovoids are encountered after annealing: cylindrical and pyramidal nanovoids. During their thermal evolution, these vacancy-type defects are interacting with dislocations favoring their local annihilation. The experimental results demonstrate a short-range interaction between nanovoid layer and dislocations, thus having potential applications for the improvement of GaN epitaxial layers quality.