Accumulation-Mode Lateral Double-Diffused MOSFET Breaking Silicon Limit by Eliminating Dependence of Specific ON-Resistance on Doping Concentration

An accumulation-mode lateral doublediffused MOSFET (LDMOS) is proposed and its mechanism is investigated in this article. To optimize the tradeoff between breakdown voltage (BV) and specific ON-resistance (R-on,R-sp), the idea of separating the breakdown area from the conduction path is designed. The N-type buffer layer is adopted to obtain ideal reverse characteristics for accumulation-mode LDMOS. The electrons are introduced to eliminate the dependence of the Ron, sp on the doping concentration of the drift region. Simulation results show that the R-on,R-sp of the proposed LDMOS is 6.83 m Omega . cm(2) with the BV of 460 V, which is less than 30.2 m Omega . cm(2) that of the conventional LDMOS with the BV of 223 V for the same drift region length of 20 mu m. Moreover, the Ron, sp of ac-NBL LDMOS is only 2.07 m Omega . cm(2), which is reduced by 93% compared with the conventional LDMOS with the same BV of 223 V. A better tradeoff between BV and R-on,R-sp can be obtained by eliminating the dependence of R-on,R-sp on the doping concentration, and the Ron, sp of ac-NBL LDMOS increases much more slowly than that of conventional LDMOS as BV increases.

Automated summary

The study introduces a novel accumulation-mode LDMOS with improved tradeoff between breakdown voltage and specific ON-resistance compared to conventional LDMOS. By eliminating the dependence of specific ON-resistance on doping concentration, better performance is achieved with the ac-NBL LDMOS showing significant improvement over the conventional LDMOS.