Improved Evaluation Method for Channel Mobility in SiC Trench MOSFETs

We proposed an improved method for evaluating the effective channel mobility ( μ eff ), involving an appropriate definition of the threshold voltage ( V th ) based on the ideal gate bias voltage – drain current ( V G - I D ) characteristics. Using this method, the dependence of μ eff on the effective field ( E eff ) could be evaluated even for SiC trench MOSFETs with large interface state density ( D it ) values. The dominant influence on μ eff in the low E eff region was found to be Coulomb scattering caused by interface states at the SiC/SiO 2 interfaces.