An epitaxial n-type 6H–SiC layer was 4-fold implanted with Al+ ions at temperatures ranging from room temperature to 1200C in order to create a buried p-doped layer some 200 to 600nm below the surface. The defects introduced by ion implantation at various temperatures were investigated by using slow positron implantation spectroscopy. Higher substrate temperatures were found to lead to a significant reduction in the depth of the damage. However, this was accompanied by the formation of vacancy clusters with sizes of up to seven Si–C di-vacancies. Only at 1200C did vacancy agglomeration disappear from the implanted region, and larger agglomerates form immediately below the surface. Furnace annealing at 1650C was found to be insufficient to remove all of the damage.

The Influence of Substrate Temperature on the Evolution of Ion Implantation-Induced Defects in Epitaxial 6H–SiC. W.Anwand, G.Brauer, H.Wirth, W.Skorupa, P.G.Coleman: Applied Surface Science, 2002, 194[1-4], 127-30