ELECTRICAL CHARACTERIZATION OF INSTABILITIES IN 6H SILICON-CARBIDE METAL-OXIDE-SEMICONDUCTOR CAPACITORS

Capacitance, charge, and current measurements have been performed on p-type 6H-SiC metal-oxide-semiconductor capacitors in order to study electrical instabilities in the SiO2/6H-SiC system and the behavior of the inversion layer at different temperatures. The analysis of hysteresis and deformation of capacitance-voltage curves shows the presence of interface states and oxide traps with a density of approximately 5-7 X 10(10) eV-1 cm-2 in the midgap and a peak of 3 X 10(12) eV-1 cm-2 at E = E(v) + 0.53 eV. Ionic contamination of the oxide layer has also been investigated, by thermally stimulated ionic current: A mobile charge concentration in the range of 10(12) cm-2 was found. Finally, it is shown, by charge-voltage measurements, that the minority-carrier generation is assisted by deep levels during the formation of the inversion layer.