PNNL

Abstract

Single crystal 4H-SiC was irradiated with 2 MeV Au ions at 165 K. Ion-induced defect configurations and damage accumulation were studied by ion-channeling techniques along the , and directions. A nonlinear dependence of damage accumulation is observed for both the Si and C sublattices along all three directions, and the relative disorder observed along the and directions is much higher than that along the direction. The damage accumulation can be described by a disorder accumulation model, which indicates that defect-stimulated amorphization is the primary amorphization mechanism in SiC, and the high disorder level for the large off-axis angles is partially attributed to a geometrical effect. Molecular dynamics (MD) simulations demonstrate that most single interstitial configurations are shielded by Si and C atoms on the lattice sites along the direction, which significantly reduces their contribution to the yield along the direction.