Optimisation of low voltage Field Plate LDMOS transistors

An alternative 3D RESURF method applied in power MOSFETs consists on placing a thick trench oxide of together with a poly-silicon layer inside the trench oxide together with a poly-silicon layer inside the trench along the drift region. The metal-thick-oxide acts as a field-plate (FP), enhancing the 3D RESURF lateral depletion which allows increasing the N-drift doping concentration. The feasibility of applying the FP concept in lateral DMOS devices has been analyzed in this paper by means of 1D analytical formulation, and by extensive 2D and 3D TCAD simulations.