A novel step buried oxide Partial SOI LDMOSFET with Triple Drift layer

A new partial-silicon-on-insulator (PSOI) power MOSFET structure is proposed, in which the drift region in the step buried oxide PSOI structure (SB-PSOI) is replaced by a triple drift region with three different doping concentrations. We call this structure Triple Drift Partial Silicon on Insulator (TDSB-PSOI). 2-D numerical simulations are performed and its results show that these three different parts in the drift region create two additional peaks in the electric field distribution along the drift region. This phenomenon causes an enhancement of about 100% in the breakdown voltage (BV) of TDSB-PSOI towards its SB-PSOI counterpart. The self-heating effect (SHE) is also improved in the proposed structure. Furthermore, our simulation results show that the output characteristic of the TDSB-PSOI exhibits a significantly higher drain current in comparison with the SB-PSOI structure. The drain current of the TDSB-PSOI and SB-PSOI structures are 112μA and 95μA, respectively at V_GS = 25V and V_DS= 70V.