PNNL

Abstract

Irradiation experiments have been performed at 100, 170 and 300 K for 6H-SiC single crystals using Au2?and He+ ions over a range of fluences. The evolution of disorder on the both Si and C sublattices has been simultaneously investigated using 0.94 MeV D? Rutherford backscattering spectrometry in combination with 12C(d,p) nuclear reaction analysis in a axial channeling geometry. The results show that the dependence of disorder on dose is consistent with a combined direct-impact / defect-stimulated model. At low doses, a slightly higher rate of C disordering is observed, which is consistent with molecular dynamics simulations that suggest a smaller threshold displacement energy on the C sublattice. At higher doses, the rate of C disordering decreases more rapidly than the rate of Si disordering, which suggests a higher rate of dynamical recovery on the C sublattice under the irradiation conditions. Three distinct recovery stages are observed on both the Si and C sublattices in the Au2?-irradiated 6H-SiC. However, complete recovery of irradiation-induced disorder does not occur during isochronal annealing at temperatures up to 970 K.