Point defects in MeV ion-implanted silicon studied by deep level transient spectroscopy

Abstract

This paper reviews recent work using deep level transient spectroscopy (DLTS) for studying point defects in crystalline silicon implanted with H, B, C, O, Si, Ge and Sn ions. Doses between 10 7 and 10 10 cm −2 and energies from 0.4 to 8 MeV were used. Different intrinsic and impurity-related defects like divacancy and vacancy-oxygen centers are identified and their formation has been studied as a function of dose, dose rate, sample depth, implantation temperature and ion mass. Recombination between vacancies and Si self-interstitials is found to play a major role and only a few percent of the generated vacancies form stable defects. Furthermore, in direct contrast to that for damage accumulation at doses above ∼ 10 12 cm −2, the production of vacancy-type defects increases with increasing implantation temperature and decreases with increasing dose rate. These effects are qualitatively simulated using a simple model for the defect generation kinetics and attributed to enhanced vacancy annihilation by overlapping Si self-interstitials from adjacent ion tracks.