Defect Formation And Annealing Behaviors Of Fluorine-Implanted Gan Layers Revealed By Positron Annihilation Spectroscopy

Defect formation and annealing behaviors of fluorine-implanted, unintentionally doped GaN layers were studied by positron annihilation spectroscopy (PAS). Single Ga vacancies (V(Ga)) were identified as the main vacancy-type defects detected by PAS after fluorine implantation at 180 keV with a dose of 1x10(15) cm(-2). Implantation-induced V(Ga) tend to aggregate and form vacancy clusters after postimplantation annealing in N(2) ambient at 600 degrees C. Fluorine ions tend to form F-vacancy complexes quickly after thermal annealing, which is consistent with the proposed diffusion model that predicts the behaviors of fluorine in GaN.