The on-resistance limit of 100 V-class Field-Plate (FP) trench power MOSFETs was analyzed by TCAD simulation. In the previous works, the lateral pitch narrowing effect to reduce the on-resistance has been studied from the viewpoint of charge compensate concept. This work focused on optimization of FP oxide thickness, which affects both the breakdown voltage and the stress induced electron mobility enhancement. The simulation results show that thin oxide structure is desired for low on-resistance design due to lateral pitch narrowing, although thick oxide enhances the increase of the electron mobility. However, the on-resistance reduction by lateral pitch narrowing is limited by increase of the drift layer thickness for maintain the breakdown voltage. As a limit value, the on-resistance of 24.7mOmm2 at the breakdown voltage of 114 V was estimated and corresponds to 13%-24% improvement of Figure-of-Merit, which is VB2.5/Ron, compared with the previous works of two step and multiple step oxide structures.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering