Normally-off 4H-SiC Trenched Gate MOSFETs with High Mobility (Preprint)

摘要

A normally-off 4H-SiC trenched gate MOSFET structure with epitaxial buried channel, coupled with improved fabrication processes has resulted in substantially improved channel mobility. Fabricated devices subject to high- temperature ohmic contact rapid thermal annealing at 850 deg. C for 5 min exhibit a peak field-effect mobility (micro(sub FE)) of 95 cm2/Vs at room temperature (25 deg. C) and 255 cm2/Vs at 200 deg. C, which are among the highest reported to date. The dependence of channel mobility and threshold voltage on buried channel depth is investigated to explore the optimum range of channel depth.