Computer simulation of disordering and amorphization by Si and Au recoils in 3C-SiC

Molecular dynamics has been employed to study the disordering and amorphiza tion processes in SiC irradiated with Si and Au ions. The large disordered domains, consisting of interstitials and antisite defects, are created in t he cascades produced by Au primary knock-on atoms (PKAs); whereas Si PKAs g enerate only small interstitial clusters, with most defects being single in terstitials and vacancies distributed over a large region. No evidence of a morphization is found at the end of the cascades created by Si recoils. How ever, the structure analysis indicates that the large disordered domains ge nerated by Au recoils can be defined as an amorphous cluster lacking long-r ange order. The driving force for amorphization in this material is due to the local accumulation of Frenkel pairs and antisite defects. These results are in good agreement with experimental evidence, i.e., the observed highe r disordering rate and the residual disorder after annealing for irradiatio n with Au2+ are associated with a higher probability for the in-cascade amo rphization or formation of a large disordered cluster. (C) 2001 American In stitute of Physics.