Generation of “interstitial atom-Vacancy” transitions upon implantation of ions into a crystal

Abstract

The modeling of diffusion motion of atoms implanted into a crystal and irradiation-induced point defects in the space beyond the projective range has been performed. It has been shown that, beyond the ion range, there arises a region strongly depleted in vacancies, which ends with a peak in the probability of recombination of interstitial atoms with vacancies and a peak in the concentration of complexes between vacancies and implanted atoms. In the process, the key role is played by the following factors: (1) the total number of irradiation-induced atoms in interstitial sites, including implanted atoms and intrinsic atoms of the crystal, exceeds the number of irradiation-induced vacancies; (2) the existence of thermodynamically equilibrium vacancies; and (3) the formation of immobile complexes of implanted atoms with vacancies. The sizes of the region with an extremely low vacancy concentration can substantially exceed the mean free path of ions and reach several tens of micrometers. The possible manifestations of the effect under consideration have been analyzed.