A design direction of low-voltage field-plate power MOSFETs for figure-of-merit (FOM) limit

The design direction of low voltage field-plate (FP) power MOSFETs was studied toward the figure-of-merit (FOM) limit by TCAD simulation. The FOMs of R on Q g, R on Q sw, and R on Q oss are considering the on-resistance and the charge required for the switching to evaluate the conduction loss and the switching loss. The results show that thin oxide and narrow mesa structure is desired for minimizing on-resistance R on A and opposite design of thick oxide and wide mesa structure is a good choice to reduce R on Q sw for high switching frequency application. In addition, the potential of R on A and R on Q sw reduction is maintained, however, it is difficult to reduce the R on Q g and R on Q oss by the design parameter optimization. It is verified that power loss reduction in whole operating condition cannot be achieved only by the design parameter optimization and requires approach from the other direction.