Physics-Based Capacitance Model of Drift Region in Laterally Diffused Metal-Oxide Semiconductor and Its Implementation with BSIM4

: A physical capacitance model is presented for the drift region in a laterally diffused metal-oxide semiconductor (LDMOS). It is derived as a surface-potential-based model of nodal charge for the drift region. The model is combined with BSIM4, which is for the intrinsic MOSFET region of LDMOS, and it is validated with TCAD and measurement data. The model accurately predicts the capacitance of each node for the entire bias region.