New superjuction LDMOS with surface and bulk electric field modulation by buffered step doping and multi floating buried layers

作者：Cao, Zhen^*; Duan, Baoxing; Yuan, Song; Shi, Tongtong; Yang, Yintang

来源：Superlattices and Microstructures, 2017, 111: 221-229.

DOI：10.1016/j.spmi.2017.06.035

• Super junction
• LDMOS
• Electric field modulation
• Breakdown voltage
• Specific on resistance

A new superjunction lateral double diffused MOSFET with surface and bulk electric field modulation (SBEFM SJ-LDMOS) by applying of multiple floating buried layers and buffered step doping is proposed in this paper. The Multiple N-type floating buried layers are embedded in P-substrate, to reduce the amount of field crowding at N+/N-buffer/P-substrate junction by spreading the vertical depletion layer, which effectively improves the bulk electric field distribution in SJ-LDMOS, and the N+/N-buffer/P-substrate junction and the auxiliary MFB layers/substrate junctions jointly sustain a high vertical breakdown voltage (BV). In addition, based on the buffered step doping layer under the SJ layer, a uniform lateral electric field at the drift region surface of the device is obtained. Therefore, the bulk and surface electric field are both optimized simultaneously in SBEFM SJ-LDMOS. Simulated results show that compared with the conventional Buffered SJ-LDMOS and BSD SJ-LDMOS, the proposed SBEFM SJ-LDMOS improves BV by 131.7% and 80.4%, respectively, at the same drift region length and with low specific ON-resistance (R-ON,R-sp). SBEFM SJ-LDMOS exhibits excellent performance with the power figure-of-merit (FOM=BV2/R-ON,R-sp) of 13.07 MW/cm(2).

• 出版日期2017-11
• 单位西安电子科技大学