Theoretical study on high-field carrier transport and impact ionization coefficients in 4H-SiC

The high-field carrier transport properties of 4H-SiC including the impact ionization coefficients are theoretically analyzed based on a full-band Monte Carlo simulation. The simulation reasonably reproduces the behaviors of the impact ionization coefficients experimentally reported, such as temperature dependence, anisotropy, and the difference between electrons and holes. The mechanisms behind these behaviors are then discussed based on the band structure of 4H-SiC.