Positron trapping at thermal vacancies in highly As-doped Si

Abstract Using positron annihilation measurements we observed the formation of thermal vacancies in highly As-doped Si. The vacancies form already at 700 K and upon cooling down the vacancies form stable vacancy-impurity complexes such as V – As 3 . Only a fraction of thermal vacancies is observed during equilibrium temperature measurements, but the quenching to room temperature reveals that the concentration of thermally generated V – As 3 defects is an order of magnitude larger. This mismatch is explained by positron detrapping from V – As 3 at high temperatures.