DEFECT GENERATION AND HEALING IN SIC POWDER SUBJECTED TO AR IMPLANTATION

A high current (20 mA), medium voltage (100 kV), large area (40 cm2) prototype ion implanter has been developed for the implantation of powders. Theoretical calculations and XRD measurements showed that about 50 vol% of the powder could be implanted. Especially SiC powder, which has been implanted with 50 and 60 kV Ar ions, exhibits a significant ion dose dependent asymmetric peak broadening towards larger d-values and an intensity reduction up to 17% within the XRD pattern. The annealing 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 have also been implanted. However, their reaction towards the Ar implantation is different. Especially B4C shows a remarkable structural stability against the introduction of defects which is thought to be related to its peculiar rhombohedral structure based on its boron icosahedra.