Analysis and design of superjunction power MOSFET: CoolMOS™ for improved on resistance and breakdown voltage using theory of novel voltage sustaining layer

Abstract

In this paper, we have observed that the drift layer of conventional power device can be modified to SJ-drift layer for improvement in the breakdown voltage (BV). Doping level of SJ-drift layer increased by one order of magnitude gives at least 5 times improvement in on resistance Ron, without reducing the BV. Further increase in the BV is possible by increasing the thickness of the SJ-drift layer where we observed the proportional increase in Ron. Theory of novel voltage sustaining layer (SJ-theory) recently published is used for the first time to analyze and design CoolMOS structure. We observed that for a fixed cell-pitch, increasing the height of drift layer proportionately increases the BV. The rate of increasing BV is higher for smaller cell-pitch. The Ron also increases proportionally. For a fixed geometry increasing doping level by one order of magnitude reduces the BV and the rate of reduction of this BV is dependent on the cell-pitch.