A Novel Si/SiC Heterojunction LDMOS With Improved Reverse Recovery and SEB Performances

In this paper, a novel 4H-SiC SOI LDMOS (referred to as PHJD-LDMOS) is proposed and systematically investigated. Distinct from the conventional structure, the PHJD-LDMOS incorporates a silicon window (a P+ layer region) to replace a partial buried oxide (BOX) layer, which simultaneously forms a heterojunction diode composed of the P+ layer and the N-buffer region. As a unipolar device, this heterojunction diode is connected in parallel with the body PiN diode, thereby contributing to improved reverse recovery characteristics. Furthermore, the silicon window provides an efficient thermal conduction path from the active region to the substrate, enabling rapid dissipation of lattice heat. This thermal management capability effectively enhances the single-event burnout (SEB) performance, which is typically degraded by localized high temperatures. Simulation results demonstrate that, compared with the conventional LDMOS (C-LDMOS), the PHJD-LDMOS exhibits superior comprehensive performance. Specifically, under the same forward current density, the reverse peak current density is reduced by about 65.3%, and the reverse recovery charge is decreased by 47.6%. Additionally, the SEB threshold voltage is improved by 30.8%, and the safe operating area (SOA) is expanded by 42.8%.