Tunable oxide-bypassed superjunction structure: breaking the silicon performance limit

We have recently reported an oxide-bypassed (OB) superjunction structure that utilizes the well-established oxide thickness control in fabrication instead of the difficult doping control in translating the unipolar on-resistance R_on versus the blocking voltage VBR tradeoff limit beyond the conventional unipolar silicon limit [Y.C. Liang et al., August 2001]. Further enhancement on the breakdown voltage to compensate process variation can be achieved by applying an external bias to the poly contact of the OB trench. This bias provides an independent control in adjusting maximum breakdown voltage. This paper describes the fabrication process and the laboratory results on the tunable oxide-bypassed superjunction structure.