DEFECTS INTRODUCED BY AR PLASMA EXPOSURE IN GAAS PROBED BY MONOENERGETIC POSITRON BEAM

Ar-plasma-induced defects in n-type GaAs were probed by a monoenergetic positron beam. The depth distribution of the defects was obtained from measurements of Doppler broadening profiles of the annihilation radiation as a function of incident positron energy. The damaged layer induced by the exposure was found to extend far beyond the stopping range of Ar ions, and the dominant defects were identified as interstitial-type defects. After 100-degrees-C annealing, such defects were annealed. Instead, vacancy-type defects were found to be the dominant defects in the subsurface region.