Point defect interaction with dislocations in silicon

We investigated the interaction of intrinsic point defects (vacancies and self-interstitials) with a partial dislocation in silicon. Using a combination of zero-temperature ab initio total energy calculations with finite temperature free-energy calculations based on an interatomic potential, we obtained energies for the relevant core defects. The formation energies of vacancies and interstitials in the core of a 30° glide partial dislocation are considerably lower (by more than 1 eV) than in the bulk. However, even at high temperatures, the predicted thermal concentration of shuffle segments, comprised of a row of vacancies or interstitials in the core, is low. Therefore, in the competition between two alternative positions (shuffle or glide {1 1 1} plane sub-sets) for the core of a 30° partial dislocation, the glide segment is strongly favored.