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 ( R
_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
_on,sp
on the doping concentration of the drift region. Simulation results show that the R
_on,sp
of the proposed LDMOS is 6.83 mΩ·cm
²
with the BV of 460 V, which is less than 30.2 mΩ·cm
²
that of the conventional LDMOS with the BV of 223 V for the same drift region length of 20 μm. Moreover, the R
_on,sp
of ac-NBL LDMOS is only 2.07 mΩ· 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,sp
can be obtained by eliminating the dependence of R
_on,sp
on the doping concentration, and the R
_on,sp
of ac-NBL LDMOS increases much more slowly than that of conventional LDMOS as BV increases.