Novel superjunction LDMOS with multi-floating buried layers

Abstract

In this paper, a novel superjunction lateral double-diffused MOSFET (SJ-LDMOS) based on the bulk electric field modulation is proposed. The new structure is characterized by adding the multiple floating buried layers (MFBL) into the substrate/epitaxial layer. In this way, the high bulk electric field under the drain diffusion edge is reduced and the overall bulk electric field distribution is optimized. In addition, the N+/P-substrate junction and the auxiliary MFBL/substrate junctions jointly sustain a high breakdown voltage (BV). Simulated results show that the BV of MFBL SJ-LDMOS is improved by about 80.4% than that of the buffered step doping (BSD) SJ-LDMOS with the same drift region length. Furthermore, compared with the N-type buffered SJ-LDMOS the BV of MFBL SJ-LDMOS significantly increases by 131.7%. Moreover, the power figure-of-merit (FOM=BV2/RON, sp) of MFBL SJ-LDMOS reaches 13.07 MW/cm2 with the excellent performance breaking the silicon limit.