Carrier transport properties in inversion layer of Si-face 4H-SiC MOSFET with nitrided oxide

We propose a method to evaluate the carrier transport properties in the inversion layer of 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs) experimentally. Our approach differs from conventional methods, which have adjusted the parameters in conventional mobility models. Intrinsic phonon-limited mobility (mu(phonon)) in the SiC MOSFET was observed by suppressing the severe impact of Coulomb scattering on the SiC MOS inversion layer by lowering the acceptor concentration (N-A) of the p-type well region to the order of 10(14) cm(-3). In this study, we investigated the carrier transport properties in the inversion layer of Si-face 4H-SiC MOSFETs with nitrided oxide. It is revealed that the mu(phonon )of the SiC MOSFET is a quarter or less than the conventionally presumed values. Additionally, surface roughness scattering is found not to be the most dominant mobility-limiting factor even at high effective normal field (E-eff) for the SiC MOSFET. These results demonstrate that conventional understanding of carrier scattering in the SiC MOS inversion layer should be modified, especially in the high E-eff region. (C) 2019 The Japan Society of Applied Physics