Performance and reliability improvements in SiC(0001) MOS devices via two-step annealing in H₂/Ar gas mixtures

While nitric oxide annealing is a standard technique for improving the performance of silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors, degradation of reliability remains a serious issue. Here, we present an alternative approach based on diluted hydrogen annealing, a process widely employed in silicon MOS technology. The key point of our approach is 2-step high-temperature hydrogen annealing before and after gate oxide deposition. A low interface state density (3.2 × 10 11 eV −1 cm −2 ) was obtained near the conduction band edge of SiC ( E c − E = 0.2 eV). High peak channel mobility (17.2 cm 2 V −1 s −1 ) and improved reliability against positive and negative bias stress were confirmed.