Experimental Realization of Ultralow ON-Resistance LDMOS With Optimized Layout

To achieve lower specific ON-resistance ( ${R}_{{ \mathrm{\scriptscriptstyle ON},\text {SP}}}$ ), a novel accumulation lateral double-diffused MOSFET (ALDMOS) characterized by a convex-shaped field plate (CFP) structure is proposed and investigated experimentally. The CFP structure above the ${N}$ -drift region consists of two diodes, with its contact regions embedding into the drain and source region. Hence, the proposed device could shrink the drift length and utilize the drift region effectively to sustain the same level of breakdown voltage in the OFF-state. Furthermore, the CFP structure enables to form a continuous electron accumulation layer at the drift surface in the ON-state. Consequently, the proposed CFP ALDMOS could obtain an ultralow ${R}_{{ \mathrm{\scriptscriptstyle ON},\text {SP}}}$ and achieve a better tradeoff relationship between BV and ${R}_{{ \mathrm{\scriptscriptstyle ON},\text {SP}}}$ . The experimental results show that the CFP ALDMOS realizes a BV of 448 V and ${R}_{{ \mathrm{\scriptscriptstyle ON},\text {SP}}}$ of 16.9 $\text{m}\Omega \cdot $ cm2 with an extremely high figure of merit of 11.87 MW/cm2, decreasing ${R}_{{ \mathrm{\scriptscriptstyle ON},\text {SP}}}$ by 55.6% compared with theoretical triple-REduced SURface Field (RESURF) LDMOS at the same BV.