The Al concentration profiles formed by the implantation of Al into SiC at room temperature, with subsequent high-temperature annealing, were analyzed. It was shown that, at doses above the amorphization threshold, the profiles exhibited a number of specific features: a shift in the distribution maximum, the accumulation of dopant near the surface and the formation of box-shaped profiles. In order to describe the redistribution of Al in SiC layers, implanted with high doses, quantitatively, a segregation–diffusion model was suggested for the first time. The model took account of the segregation of dopants between the a- and c-phases during solid-state epitaxial crystallization followed by the diffusion of dopants and their evaporation from the surface. The formation of box-shaped Al profiles, as a result of rapid thermal annealing, was attributed to the high diffusion coefficient of dopant in the highly damaged single-crystal and polycrystalline SiC layers in the recrystallized region, and to the suppression of their enhanced transient diffusion in the remaining single-crystal part of the implanted layer.

Diffusion of Al from Implanted SiC Layer. O.V.Aleksandrov, E.V.Kalinina: Physica B, 2009, 404[23-24], 4764-7