Effects of high-temperature diluted-H2 annealing on effective mobility of SiC MOSFETs estimated by split capacitance–voltage technique

Abstract

The effects of post-oxidation annealing (POA) in diluted-H2 ambient on 4H- and 6H-SiC/SiO2 interfaces were investigated. Effective mobility (μeff) was extracted from lateral metal–oxide–semiconductor field-effect transistors (MOSFETs) by the split capacitance–voltage (C–V) technique to determine the surface charge density and a calibration technique using two MOSFETs with different gate lengths to minimize the contribution of parasitic components. POA at 1150 °C in diluted-H2 ambient resulted in an enhancement of μeff, compared with that in N2 ambient. It was indicated that the effects of POA in diluted-H2 ambient should be attributed to the reduction in the density of near-interface traps in oxide, which disturb the electron transportation in the inversion channel, from the measurement temperature dependence of μeff for 6H-SiC MOSFETs as well as from the C–V curves of MOS capacitors fabricated on n-type 4H-SiC.