Impacts of band alignment change after interface nitridation on the leakage current of SiO_2/4H-SiC (0001) and (1100) MOS capacitors

摘要

The band alignments and leakage currents were investigated after post-oxidation annealing in NO ambient (NO-POA) for SiO2/4H-SiC (0001) and ( 11 over bar 00 i ) metal-oxide-semiconductor capacitors. Significant increase in conduction band offset was observed after NO-POA on SiO2/4H-SiC (0001) interface whereas decrease on SiO2/4H-SiC ( 11 over bar 00 i ) interface, which would be related to different dipoles direction on (0001) and ( 11 over bar 00 i ) faces, respectively. We found that leakage currents originated by both Fowler-Nordheim tunneling and Poole-Frenkel emission were significantly higher on ( 11 over bar 00 i ) than on (0001) after NO-POA at elevated temperatures, indicating that band alignment should be considered as important factor to employ various crystal faces for power devices.