Ion-beam-induced dissociation and bubble formation in GaN

Structural studies reveal that heavy ion bombardment of GaN causes amorphization and anomalous swelling of the implanted region as a result of the formation of a porous structure. Results strongly suggest that such a porous structure consists of N2 gas bubbles embedded into a highly N-deficient amorphous GaN matrix. The evolution of the porous structure in amorphous GaN appears to be a result of stoichiometric imbalance where N- and Ga-rich regions are produced by ion bombardment. Prior to amorphization, ion bombardment does not produce a porous structure due to very efficient dynamic annealing processes in the crystalline phase.