Effects of Ar and H2 annealing on the electrical properties of oxides on 6H SiC

We report on the influence of post-oxidation annealing (POA) on the electrical properties of metal-oxide-semiconductor capacitors fabricated on n- and p-type 6H SiC (Si face). All samples were oxidized in dry or wet oxygen at 1150 °C. POA at this temperature reduces the densities of fixed oxide charges and interface states. Negative fixed oxide charges on n-type SiC were found to be located at the SiO2SiC interface. High temperature H2 annealing experiments show that hydrogen plays a critical role in the SiO2SiC system. Oxide defects on p-type SiC, which are believed to result from dopant (Al) incorporation in SiO2, could be passivated by annealing in forming gas.