Improved inversion channel mobility for 4H-SiC MOSFETs following high temperature anneals in nitric oxide

Results presented in this letter demonstrate that the effective channel mobility of lateral, inversion-mode 4H-SiC MOSFETs is increased significantly after passivation of SiC/SiO2 interface states near the conduction band edge by high temperature anneals in nitric oxide. Hi-lo capacitance-voltage (C-V) and ac conductance measurements indicate that, at 0.1 eV below the conduction band edge, the interface trap density decreases front approximately 2 x 10(13) to 2 x 10(12) eV(-1)cm(-2) following anneals in nitric oxide at 1175 degreesC for 2 h. The effective channel mobility for MOSFETs fabricated with either wet or dry oxides increases by an order of magnitude to approximately 30-35 cm(2) /V-s following the passivation anneals.