Enhanced oxidation of ion-damaged 6H-SiC

Thermal oxidation of the Si face of 6H-SiC was investigated in single-crystal and ion-implanted material. The samples were irradiated with Si and Kr ions at different fluences and the damage produced was studied with Rutherford back scattering in the channelling configuration. The oxidation was performed at a temperature of 1150¬?C for times ranging from 1 to 10h. The oxide thickness was measured by Rutherford back-scattering and ellipsometric measurements. It was found that the oxidation rate in ion-damaged 6H-SiC is larger than in unimplanted samples. The oxide thickness increases with increasing ion fluence and it saturates at a fluence corresponding to complete amorphization of the surface layer. The enhanced oxidation is ascribed to breakdown of the strong covalent Si-C bonds induced by ion irradiation, resulting in an increase in the chemical reactivity. Capacitance-voltage measurements, performed in order to characterize the oxide layer, show the presence of a large amount of charge in the oxide grown on damaged SiC samples.