Molecular dynamics methods, and a modified Tersoff potential, were used to simulate high-energy (50keV) displacement cascades in the β-phase. The results showed that the cascade lifetime was very short; 10 times shorter than that in metals. The surviving defects were dominated by C interstitials and vacancies. This was similar to the behavior of 10keV cascades in SiC. Antisite defects were generated on both sub-lattices. Although the total number of antisite defects which remained at the end of the cascade was smaller than that of Frenkel pairs, the number of Si antisites was larger than the number of Si interstitials. Most of the surviving defects were single interstitials and vacancies, and only 19% of the interstitial population was contained in clusters. The size of the interstitial clusters was small, and the largest cluster found contained only 4 interstitial atoms. This was a significantly different behavior to that predicted by molecular dynamics simulations of metals. It was observed that all of the clusters were created, by a quenched-in mechanism, directly from the collisional phase of the cascade. The initial Si recoil travelled some 65nm on average; generating multiple sub-cascades and forming a dispersed arrangement in the cascade geometry. The results suggested that in-cascade or direct-impact amorphization in SiC did not occur, with any high degree of probability, during the lifetime of Si cascades; even for high-energy recoils. This was consistent with previous experimental and molecular dynamics observations.

Atomic-Scale Simulation of 50KeV Si Displacement Cascades in β-SiC. F.Gao, W.J.Weber: Physical Review B, 2001, 63[5], 054101 (7pp)