Performance Analysis of Silicon Carbide MOSFETs Using Silicon Dioxide and Silicon Nitride Gate Dielectrics

The demand for advanced power electronics is driving the development of more efficient and reliable semiconductor devices. This study investigates the impact of different gate dielectric materials, specifically silicon dioxide (SiO2) and silicon nitride (Si3N4), on the performance of silicon carbide (SiC)-based MOSFETs. SiC has emerged as a superior substrate for high-power, high-frequency applications due to its wide bandgap, higher breakdown voltage, and better thermal stability compared to traditional silicon. Using finite element analysis through COMSOL Multiphysics®, this research compares key parameters such as electron mobility, terminal current, and threshold voltage in MOSFETs with SiO2 and Si3N4 gates. The results demonstrate that while SiO2 provides smoother modulation of dopant concentrations and electron flow, Si3N4 exhibits stronger control over electric potential and carrier distribution, resulting in enhanced switching speed and efficiency, Specifically, Si3N4 demonstrated a 15% higher terminal current and a 0.2V reduction in turn-on voltage compared to SiO2 in the SiC MOSFET and stabilizing threshold voltage. These findings contribute to the optimization of wide-bandgap semiconductor devices, offering insights for improving MOSFETs in next-generation power systems.