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

An accumulation-mode lateral double-diffused MOSFET (LDMOS) is proposed and its mechanism is investigated in this article. To optimize the tradeoff between breakdown voltage (BV) and specific on-resistance (Ron,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 Ron,sp of the proposed LDMOS is 6.83 mΩ · cm² with the BV of 460 V, which is less than 30.2 mΩ · cm² that of the conventional LDMOS with the BV of 223 V for the same drift region length of 20 μm. Moreover, the Ron,sp of ac-NBL LDMOS is only 2.07 mΩ · cm², which is reduced by 93% compared with the conventional LDMOS with the same BV of 223 V. A better tradeoff between BV and Ron,sp can be obtained by eliminating the dependence of Ron,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.