Diffusion of boron in silicon carbide: Evidence for the kick-out mechanism

We report diffusion experiments of implanted boron (B) in nitrogen-doped 4H- and aluminum-doped 6H-SiC which were performed at temperatures between 1700 and 1800 °C. Transient enhanced B diffusion caused by implantation damage was effectively suppressed by annealing of the B-implanted samples at 900 °C prior to the diffusion anneal. Concentration profiles of B measured with secondary ion mass spectrometry are accurately described on the basis of the kick-out mechanism. This provides strong evidence that Si self-interstitials mainly mediate B diffusion.