Comparison of Impact Ionization Models for 4H-SiC Along the <0001> Direction, Through Breakdown Voltage Simulations at Room Temperature

A comparative study of the simulated breakdown voltage of 4H-SiC devices has been conducted for the most widely used impact ionization models (Selberherr, Hatakeyama), based on the experimental data of 4H-SiC pn diodes. The effect of mesh density on the simulated breakdown voltage has been examined. The TCAD simulations employing default commercial simulators parameters did not converge to a value close to the experimentally observed as the mesh density is increased. Various experimental ionization parameters, as reported in the bibliography, have been examined instead of the commercial-TCAD-simulators default ones. Simulations with optimal parameters result in convergence to breakdown voltage values close to the experimentally measured ones when the mesh density is increased.