Physics-based numerical modeling and characterization of 6H-silicon-carbide metal-oxide-semiconductor field-effect transistors

A detailed analysis of silicon-carbide (SiC) metal-oxide-semiconductor field-effect-transistor (MOSFET) physics is performed. Measurements of current-voltage characteristics are taken. A device simulator is developed based on the drift-diffusion equations. The model accounts for incomplete ionization. Comprehensive mobility and interface state models are developed for SiC MOSFETs. The mobility model accounts explicitly for bulk transport, as well as for interface states, surface phonons and surface roughness. Agreement between simulated and measured terminal characteristics is obtained. The results provide values for interface state occupation as a function of energy and position along the surface. Results giving values for surface mobility as a function of position along the channel indicate that interface states have an especially strong effect on SiC operation. Our investigation indicates that substantial reduction of interface states can give rise to a fivefold increase in transconductance.