COMPUTER-SIMULATION OF A 10 KEV SI DISPLACEMENT CASCADE IN SIC

The threshold energy for atomic displacement and the evolution of high -energy displacement cascades in beta-SiC have been examined using mol ecular dynamics simulations. A modified form of the Tersoff potential was used in combination with a repulsive potential obtained from densi ty functional theory to describe the interactions between the atoms. T he evolution of lattice damage in a 10 keV Si cascade was studied for about 10 ps. The system size varied from 8000 atoms for the displaceme nt energy calculations to 192,000 atoms for the cascade simulations. T he results indicate that the minimum displacement energy is about 36 e V for Si and 28 eV for C. The cascade lifetime was found to be of the order of 0.1 ps, and the surviving C vacancies and interstitials outnu mbered the corresponding Si defects by a factor of about 3. These resu lts are discussed in light of previous theoretical and experimental st udies of radiation damage in SiC. (C) 1998 Elsevier Science B.V. All r ights reserved.