Novel LDMOS with assisted deplete-substrate layer consist of super junction under the drain

Abstract

A novel lateral double-diffused MOSFET (LDMOS) is proposed with the assisted deplete-substrate layer (ADSL) under the drain electrode for the first time in this letter. Since the introduced layer could assist deplete the substrate, both the lateral and the vertical electric field distributions would be improved resulting from the electric field modulation effect, the breakdown characteristic is significantly improved. The results show that the breakdown voltage (BV) of the proposed ADSL LDMOS is increased from 464 V of the conventional LDMOS to 812 V with the same 70 μm drift region length. Furthermore, the figure-of-merit (FOM) for ADSL LDMOS and the conventional LDMOS are 1.397MW/cm2 and 0.645 MW/cm2, respectively. The ADSL LDMOS has a much better performance than the conventional LDMOS.