Primary damage states produced by Si and Au recoils in SiC: A molecular dynamics and experimental investigation - art. no. 214106

Molecular dynamics (MD) simulations, experimental studies, and a theoretica l model have been combined in an investigation of the disordering and amorp hization processes in SiC irradiated with Si and Au ions. In MD simulations , large disordered domains, consisting of interstitials and antisite defect s, are created in the cascades produced by Au primary knock-on atoms (PKAs) ; whereas Si PKAs generate only small interstitial clusters, with most defe cts being single interstitials and vacancies distributed over a large regio n. The data for a cluster spectrum obtained from MD simulations have been u sed to calculate the relative cross sections for in-cascade amorphization ( or clustering) sigma (DI) and in-cascade defect-stimulated amorphization si gma (DS). The ratio of these-cross sections, sigma (DS)/sigma (DI), for Si and Au is in excellent agreement with those derived from the experimental d ata based on a fit of the direct-impact-defect-stimulated model. This sugge sts that the observed higher disordering rate and the residual disorder aft er thermal annealing at 300 K for irradiation with Au2+ are associated with a higher probability for in-cascade amorphization or large disordered clus ter formation. The observed different behavior for the accumulation and rec overy of disorder in SiC irradiated by Si+ and Au2+ is qualitatively consis tent with the present MD simulations and the direct-impact-defect-stimulate d model.