Challenges in SiC power MOSFET design

The impact of fundamental and technological parameters is considered for SiC power MOSFETs. The wide bandgap nature of SiC increases the surface electric field by 2× at inversion compared to silicon, placing an important role on surface roughness in reducing the field-effect mobility. The presence of interface-trapped charges also acts to reduce the channel mobility and increases the sensitivity of the threshold voltage to temperature. The high critical electric field of SiC increases the stored energy in the switch output capacitance by 10× compared to silicon. For hard-switched converters, it is important to design SiC MOSFETs with a high saturation current to enable high-speed turn-on transients required to discharge the integral drain-source capacitance.