New Super-Junction LDMOS Breaking Silicon Limit by Multi-Ring Assisted Depletion Substrate

Abstract

A novel super-junction (SJ) lateral double-diffused MOSFET with the multi-ring substrate (M-R SJ-LDMOS) is proposed for the first time. The substrate-assisted depletion (SAD) effect is eliminated by the n-type M-R to realize a balanced symmetric SJ with the low specific ON-resistance ( ${R}_{\text {on,sp}}$ ). Meanwhile, more uniform lateral and vertical electric field distributions are obtained under the surface and bulk electric field modulation effect, which leads to the enhancement of breakdown voltage (BV). The simulation results show that the BV of M-R SJ-LDMOS is increased by 427.2% and 81.2% in comparison with the conventional SJ-LDMOS and buffered step doping (BSD) SJ-LDMOS with the same drift region length, respectively. In addition, ${R}_{\text {on,sp}}$ of M-R SJ-LDMOS is reduced by 18.6% and 80.3% than that of BSD SJ-LDMOS and the conventional SJ-LDMOS. The figure-of-merit (FOM) of M-R SJ-LDMOS is 5.81 MW/cm2, which means the performance of M-R SJ-LDMOS is so excellent to break the silicon limit. +Moreover, the application of highly doped substrate ( ${3} \times {10}^{{15}}$ cm−3) in M-R SJ-LDMOS cuts the cost of substrate.