A non-linear dependence of damage disorder on dose was observed for both Si and C sub-lattices in 4H-SiC under 2MeV Au irradiation at 165K. The relative disorder observed along the <¯44▪¯3> direction was much higher than that along the <00▪1> direction. Molecular dynamics simulations demonstrated that most interstitial configurations were formed on the Si-C dimer rows that were parallel to the <00▪1> direction. As a result, these interstitials were shielded by the Si and C atoms on the lattice sites, which significantly reduces the contribution of these interstitials to the back-scattering/reaction yield along the <00▪1> direction. During isochronal annealing below room temperature, the relative disorder decreased along the <00▪1> direction, as expected; however, the disorder was stable on the Si sub-lattice and increased slightly on the C sub-lattice when measured along the <¯44▪¯3> direction due to relaxation of some metastable defects to lower energy configurations. As the annealing temperature increased, similar recovery behavior on both Si and C sub-lattices along the <00▪1> direction indicated coupling of Si and C recovery processes; however, slightly higher recovery temperatures on the C sub-lattice along the <¯44▪¯3> direction suggested some decoupling of the Si and C recovery processes. Based on the structures and energetics of defects from molecular dynamics simulations, new insights into defect configurations and relaxation processes were described.

Damage Accumulation and Defect Relaxation in 4H-SiC. Y.Zhang, F.Gao, W.Jiang, D.E.McCready, W.J.Weber: Physical Review B, 2004, 70[12], 125203 (7pp)