Characterization of High-Energy-Heavy-Ion-Induced Defects in GaAs by Positron Annihilation

The defects induced by 64 MeV ¹⁹F ion irradiation to a Auence of 4.3 ×10¹⁶/cm² are investigated in GaAs by positron annihilation lifetime technique. Di-vacancies are created by the irradiation. The formation of tri- and quadri-vacancies is observed during thermal annealing. The di-, tri-and quadri-vacancies are annealed away at 350, 550 and 800°C, respectively.