Enhanced annealing of implantation-induced defects in 4H-SiC by thermal oxidation

Annealing of the prominent Z(1/2) defect in 4H-SiC has been studied after thermal treatment in N-2 and O-2 atmospheres at 1150 degrees C subsequent to implantation with MeV Si-ions to doses in the range of (1-4) x 10(8) cm(-2). The annealing rate is found to be significantly enhanced under oxidizing conditions, while in N-2 atmosphere Z(1/2) remains stable. Hence, a substantial lowering of the annealing temperature required for defect removal in 4H-SiC doped by ion-implantation may be expected using oxidizing annealing atmosphere. Concentration versus depth profiles of Z(1/2) clearly show that it is annihilated by defect species injected from the SiO2/4H-SiC interface during oxidation. The injection rate of the in-diffusing species is found to be about (1.2 +/- 0.2) x 10(6) cm(-2) s(-1), and the concentration ratio of the injected species relative to the native atoms originally present in the oxidized volume is similar to 1 x 10(-7). A model where the annihilating species are injected from the surface with a diffusion coefficient of about 10(-8) cm(2)/s yields excellent agreement with the experimental data. (C) 2011 American Institute of Physics. [doi:10.1063/1.3531755]