Impact ionization coefficients of 4H- and 6H-SiC

The Monte Carlo (MC) simulation of electron and hole impact ionization rates for 4H- and 6H-SiC in high electric field is presented. This work focuses on the study of impact ionization rates and impact ionization coefficients since these parameters play a very important role in determining the device performance. In our simulation, the impact ionization rates are obtained by using modified Keldysh equation with a softness factor fitted to the experimental data described by other researchers. The electron and hole impact ionization coefficients in 4H- and 6H-SiC are parameterized at high electric field. The electron and hole impact ionization coefficients for a wide range of electric fields have been successfully derived in our model