Impacts of material parameters on breakdown voltage and location for power MOSFETs

Abstract

To improve the electrical performance of power devices, materials used in fabrication need to be analyzed and optimized. By numerical simulations, we reveal that the breakdown voltage (BV) and location of a lateral diffused MOS power device simultaneously depend on trench oxide permittivity. For a given device geometry, while trench oxide permittivity with a certain value leads to a maximal BV, a smaller (larger) value causes electrical breakdown in the Si drift channel around the bottom (top) of the trench. This trend stays the same when Si is replaced by SiC. Our study implies that any byproduct reducing the trench permittivity during trench lling should be avoided.