Suppressed diffusion of implanted boron in 4H–SiC

Abstract
Transient-enhanced diffusion of boron (B) during anneals at 1700 °C is experimentally observed in B-implanted 4H–SiC samples. This enhanced diffusion can strongly be suppressed by coimplantation of carbon or by a preanneal at 900 °C. It is proposed that B in 4H–SiC diffuses via the kick-out mechanism with the assistance of silicon interstitials in analogy to the B diffusion in Si. From the Fickian diffusion tail into the undamaged bulk, the preexponential factor D0 and the activation energy EA of the B diffusion coefficient D(B,T) are determined.