Observation of interface defects in thermally oxidized SiC using positron annihilation

Positron annihilation spectroscopy was used to study thermally oxidized 4H- and 6H-SiC. The SiC/SiO₂ interface contained a high density of vacancy defects that acted as positron traps. Observation of these traps correlated with the negative charge of the interface determined by capacitance-voltage experiments. The positron annihilation characteristics indicated that these vacancy defects possessed neighboring oxygen atoms.