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

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 (Ron,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, Ron,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/cm
²
, 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 × 1015 cm
^-3
) in M-R SJ-LDMOS cuts the cost of substrate.