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

Abstract

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 ( ${R}_{\text {on,sp}}$ ), 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 ${R}_{\text {on,sp}}$ on the doping concentration of the drift region. Simulation results show that the ${R}_{\text {on,sp}}$ of the proposed LDMOS is 6.83 $\text{m}\Omega \cdot \text {cm}^{{2}}$ with the BV of 460 V, which is less than 30.2 $\text{m}\Omega \cdot \text {cm}^{{2}}$ that of the conventional LDMOS with the BV of 223 V for the same drift region length of $20~\mu \text{m}$ . Moreover, the ${R}_{\text {on,sp}}$ of ac-NBL LDMOS is only 2.07 $\text{m}\Omega \cdot \text {cm}^{{2}}$ , which is reduced by 93% compared with the conventional LDMOS with the same BV of 223 V. A better tradeoff between BV and ${R}_{\text {on,sp}}$ can be obtained by eliminating the dependence of ${R}_{\text {on,sp}}$ on the doping concentration, and the ${R}_{\text {on},\text {sp}}$ of ac-NBL LDMOS increases much more slowly than that of conventional LDMOS as BV increases.