The influence of substrate temperature on the evolution of ion implantation induced defects in epitaxial 6H-SiC

An epitaxial n-type 6H-SiC layer has been fourfold implanted with Al+ ions at temperatures ranging from room temperature to 1200 oC in order to create a buried p-doped layer from 200 nm to 600 nm below the surface. The defects induced by the ion implantation at different temperatures have been investigated by Slow Positron Implantation Spectroscopy. 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 divacancies. Only at 1200 ºC does the vacancy agglomeration disappear in the implanted region, and larger agglomerates are formed immediately below the surface. Furnace annealing at 1650 ºC was found to be insufficient to remove all damage.