Numerical Investigation on L-Shaped Vertical Field Plate in High-Voltage LDMOS

Abstract In this work, an L-shaped vertical field plate (LVFP) is introduced in high-voltage lateral double-diffused MOSFET (LDMOS). The LVFP is embedded in an oxide trench that penetrates into the drift region. Compared with the conventional vertical field plate (VFP), the electric field surrounding the trench is enhanced for LVFP, and the depletion can penetrate deeper into the bulk silicon drift region. This improves the depletion of the drift region and thus the drift doping concentration (Nd). Consequently, the breakdown voltage (BV) increases while the on-resistance (Ron) decreases. The simulation results show that in comparison to the VFP device, the proposed device can achieve higher BV (= 833 V) and lower Ron (= 24.9 mΩ∙cm2).