DEFECT GENERATION AND HEALING IN SIC POWDER SUBJECTED TO AR IMPLANTATION

A high current (20 mA), medium voltage (100 kV), large area (40 cm2) p rototype ion implanter has been developed for the implantation of powd ers. Theoretical calculations and XRD measurements showed that about 5 0 vol% of the powder could be implanted. Especially SiC powder, which has been implanted with 50 and 60 kV Ar ions, exhibits a significant i on dose dependent asymmetric peak broadening towards larger d-values a nd an intensity reduction up to 17% within the XRD pattern. The anneal ing behaviour of these defects is discussed. Partly, these defects are stable beyond 1000-degrees-C. The results are compared and confirmed by RBS experiments from SiC single crystals. B4C, TiC and WC powders h ave also been implanted. However, their reaction towards the Ar implan tation is different. Especially B4C shows a remarkable structural stab ility against the introduction of defects which is thought to be relat ed to its peculiar rhombohedral structure based on its boron icosahedr a.