Design and fabrication of superjunction power MOSFET devices

Abstract

The originally proposed superjunction power MOSFET structures are highly recognized for their higher voltage blocking capability and lower specific on-state resistance. However, their performance is greatly handicapped by the limitation of fabrication process technology. Recently developed structures of Polysilicon Flanked Superjunction (PF-SJ) and Oxide-bypassed Superjunction (OB-SJ) MOSFETs were designed to overcome the conventional superjunction device fabrication limitation. The follow-up development on extending the scope of these recently reported device structures to the lateral superjunction structures, suitable for the superjunction power integrated circuits, is investigated in this work. Detailed descriptions on the progressive development and the technical advancement of several superjunction MOSFET structures are presented with both simulation and experimental results. Complete theories and closed-form derivations on SJ, OB superjunction structures are also studied to gain a thorough understanding of superjunction theory and establish a theoretical framework for the existing superjunction devices. Novel device structure is also proposed.