Transient enhanced diffusion of aluminum in SiC during high temperature ion implantation

Abstract

6H–SiC wafers were implanted at room temperature (RT) and at 1700 °C high temperature (HT) with 50 keVAl+ ions to doses from 1.4×1014 to 1.4×1016 cm−2. Compared to samples implanted at RT, the samples implanted at high temperature display considerable aluminum redistribution. The diffusion of Al is shown to be a transient effect with different decay times in the near-surface region and in the bulk. Investigation of the crystalline structure indicated that in the near-surface region dislocation loops grow in size and Al precipitates are formed as the dose of Al implanted at HT is increased. Changes in the structure of the implanted layer may have a strong effect on the redistribution of Al. The observed redistribution can be explained by a dissociative diffusion mechanism during the high-temperature implantation.