A new 2D analytical model of double RESURF in SOI high voltage devices

A new 2D analytical model of the double RESURF in SOI high voltage devices is proposed in the paper. Based on the 2D Poisson equation, an analytical distribution of the surface field is obtained. A unified condition of single and double RESURFF for the SOI device, taking the both influence of the silicon layer and buried oxide layer into account, is developed in the first time, which is different with tradition one of the bulk silicon devices, in which the silicon layer is only considered . According to the model, the electric field reduction mechanism of the P-top layer is discussed, and a RESURF doping optimal region (DOR) for optimizing the drift region concentration is given. Numerical simulations are performed to verify the present model and optimize the structure parameters. As a result, the 720V double REURF SOI LDMOS are manufactured successfully. The numerical simulation and experimental results are shown to support the analytical model.