Impact Ionization Coefficients of Electrons and Holes in 4H-SiC

Abstract

The Monte Carlo (MC) simulation of carrier transport properties at high electric field region in 4H‐SiC is presented. This MC model includes two non‐parabolic conduction bands where the electron and hole drift processes as well as the scattering processes are simulated as a function of applied electric field ranging from 1×104 V/cm to 1×106 V/cm in room temperature. As a wide bandgap semiconductor material, impact ionization rate plays a very important role in determining the carrier transport. Our simulation uses Keldysh model with a softness factor is simulated and compared to the other experimental data described by other researchers in their full band MC model. In addition, electron and hole ionization coefficients have also been derived from our model by taking an average distance that the carrier had traveled before it impact ionize. The simulated drift velocity with electric field dependency is in a good agreement with experiment results from other researchers found in literature. The simulation model clearly shows complete electron and hole transport properties in 4H‐SiC.