Si Displacement Cascades Revealed by Atomic-Scale Simulations in 3C-SiC

Abstract

The primary damage by displacement cascades in 3C-SiC at 300 K has been studied by molecular dynamics (MD). A large number of cascades, with energies from 0.2 to 50 keV, have been simulated in order to investigate the effects of energy in defect production and clustering. The surviving defects are dominated by C interstitials and vacancies. The number of Frenkel pairs increases with increasing cascade energy, but the efficiency of their production declines with increasing energy in a similar fashion to that found in metals. Although the number of antisite defects is smaller than that of Frenkel pairs, their production also increases with increasing cascade energy. Most surviving defects are single interstitials and vacancies, and the tendency of interstitials to form clusters is very week. The size of the interstitial clusters is very small, which shows significantly different behavior than obtained by MD simulations in metals. The current results provide the statistics of the primary damage states in SiC as a function of primary knock-on energy, which are important in upscaling these results to model behavior over longer time and length scales.