Modeling of Breakdown Voltage for SOI Trench LDMOS Device Based on Conformal Mapping

An analytical model is proposed in this paper to predict the breakdown voltage (BV) of silicon-on-insulator (SOI) trench lateral double diffused metal oxide semiconductor (LDMOS) devices with N/P pillars. In this SOI trench LDMOS device, the U-shaped folded drift region is divided into four parts for simplifying the solution of Poisson's equation, where conformal mapping by the Schwarz-Christoffel (S-C) transformation is applied. As verified by the TCAD simulation results, the analytical model may predict the electric field distribution and the BV accurately. This analytical model can reveal the essence of the electric field peaks around the dielectric trench from the depletion effect of the N/P pillars.