A Trench LDMOS Improved by Quasi Vertical Super Junction and Resistive Field Plate

An improved trench lateral double-diffused MOSFET (T-LDMOS) is proposed. It has a quasi vertical super junction (QVSJ) drift region and adopts a resistive field plate (RFP) to help QVSJ satisfy charge-balance. The realization of RFP barely complicates the device fabrication, but it motivates QVSJ to significantly improve the relationship between breakdown voltage (BV) and specific on-state resistance (R
_ON,SP
). The simulation results show that compared with the conventional QVSJ T-LDMOS, the proposed one gains the R
_ON,SP
reduced by about 79% under the same BV requirement of about 500 V. It therefore presents an excellent figure of merit (FOM) (FOM = BV
²
/R
_ON,SP
, Baliga's FOM) up to 29.8 MW/cm
²
, which is superior to the prior art and exhibits a bright prospect of saving energy.