An epitaxial n-type 6H-SiC layer has been four-fold implanted with Al+ ions at temperatures ranging from room temperature (RT) to 1200 degreesC in order to create a buried p-doped layer from 200 to 600 nm below the surface. The defects induced by the ion implantation at different temperatures have been investigated by slow positron implantation spectroscopy (SPIS). Higher substrate temperatures were found to lead to a significant reduction in the depth of the damage. However, this is accompanied by the formation of vacancy clusters of sizes up to seven Si-C di-vacancies. Only at 1200 degreesC does the vacancy agglomeration disappear in the implanted region and larger agglomerates are formed immediately below the surface. Furnace annealing at 1650 degreesC was found to be insufficient to remove all damage. (C) 2002 Elsevier Science B.V. All rights reserved.