Improved Characteristics of SiC MOSFETs by Post-Oxidation Annealing in Ar at High Temperature

Abstract

Post-oxidation annealing (POA) in Ar at high temperature has been performed during fabrication of 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs). The gate oxides were formed by thermal oxidation followed by N2O annealing, then annealed in Ar for 30 min or 5 h at 1300 °C. The results of Secondary Ion Mass Spectrometry (SIMS) measurements indicated that the C atoms accumulated at the SiO2/SiC interface by thermal oxidation diffused during the 5h-Ar annealing. The characteristics of n-channel MOSFETs were improved and the peak value of field effect mobility was increased to 33 cm2/Vs from 19 cm2/Vs by extending the Ar annealing time.