Higher electrical activation of ion-implanted Si over S in GaSb epitaxial layers

Abstract Ion implantation of the amphoteric dopant Si compared to the natural n-type dopant S in GaSb epitaxial films results in a higher dopant activation with better surface morphology and crystallinity. GaSb films were grown by molecular beam epitaxy (MBE) on semi-insulating GaAs (001) substrates. Ion implantation for both ions was carried out at an energy of 50 keV and a fluence of 1 × 1015 ions/cm2. Raman spectroscopy revealed a better crystallinity as well as a lower Sb out-diffusion for Si implantation as compared to S after annealing. Van der Pauw Hall measurements confirm the donor nature of the amphoteric dopant Si and with a dopant activation that is 3 times higher than the natural donor S. The electrical activation for both implants increases significantly after thermal annealing. Using temperature (20 K–300 K) vs conductivity measurement and displacement per atom (dpa) estimation, implantation-induced defect-related conduction mechanism is discussed. The results suggest the scope of Si as a viable n-type dopant in GaSb.