The accumulation of damage arising from the overlap of 10keV Si displacement cascades at 200K was investigated. Interstitial clustering, system energy and volume changes were investigated as the damage states evolved due to cascade overlap. An amorphous state was achieved at a damage energy density of 27.5eV/atom (0.28dpa). At low dose-levels, most defects were produced as isolated Frenkel pairs, with a small number of defect clusters involving only 4 to 6 atoms. However, following the overlap of 5 cascades (0.0125dpa), the size and number of interstitial clusters increased with increasing dose. The average energy per atom increased linearly with increasing short-range (or chemical) disorder. The volume change exhibited 2 regimes of linear dependence upon system energy, and increased more rapidly with dose than did either the energy or the disorder. This indicated a significant contribution to swelling by isolated interstitials and antisite defects. The saturation volume change for the cascade-amorphized state in thesesimulations was 8.2%. This was in reasonable agreement with the experimental value of 10.8% for neutron-irradiated SiC.

Atomic-Scale Simulations of Cascade Overlap and Damage Evolution in Silicon Carbide. F.Gao, W.J.Weber: Journal of Materials Research, 2003, 18[8], 1877-83