Novel Isolation Structure for High-Voltage Integrated Superjunction MOSFETs

摘要

A novel isolation structure for high-voltage integrated superjunction (SJ) MOSFETs is proposed in this letter. The structure consists of serial lateral SJ diodes with etched underlying n-buffer layers and n-substrates. A theoretical analysis shows that its breakdown voltage is determined by both the number of serial diodes and the doping concentration of pillars. Two SJ MOSFETs of a half-bridge leg can be integrated on a single chip by using the proposal structure. The isolation region for 10 A devices designed with a pillar concentration of 4 x 10(-15) cm(-3) occupies only 2.7% of the chip area. Breakdown initially occurs in the device area. A transient simulation using a resonance circuit reveals that the two SJ MOSFETs can work without interfering with each other.