Improvement of Channel Mobility in 4H-SiC C-Face MOSFETs by H2 Rich Wet Re-Oxidation

Abstract

4H-SiC(000-1) C-face was oxidized in H2O and H2mixture gas (H2rich wet ambient) for the first time. H2rich wet ambient was formed by the catalytic water vapor generator (WVG) system, where the catalytic action instantaneously enhances the reactivity between H2and O2to produce H2O. The dependence of SiC oxidation rate on the H2O partial pressure was investigated. We fabricated 4H-SiC C-face MOS capacitor and MOSFET by the H2rich wet re-oxidation following the dry O2oxidation. The density of interface traps was reduced and the channel mobility was improved in comparison with the conventional O2rich wet oxidation.