A new partial-SOI LDMOSFET with modified electric field for breakdown voltage improvement

For the first time, we report a novel partial-silicon-on-insulator (PSOI) lateral double-diffused MOS field-effect transistor where the buried oxide layer consists of two sections with a step shape in order to increase the breakdown voltage. This new structure is called step buried oxide PSOI (SB-PSOI). We demonstrate that an electric field was modified by producing two additional electric field peaks, which decrease the common peaks near the drain and source junctions in the SB-PSOI structure. Two-dimensional simulations show that the breakdown voltage of SB-PSOI is nearly four to five times higher in comparison to its PSOI counterpart. Moreover, we elucidate operational principles, as well as design guidelines, for this new device.