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

Abstract

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 (μphonon) 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 (NA) of the p-type well region to the order of 1014 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 μphonon 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 (Eeff) 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 Eeff region.