A variation laterl doping layer and lightly doped region compensated superjunction LDMOS

A new solution based on the concept of a variation lateral doping (VLD) compensated layer and a lightly doped region (LDR) is proposed for the superjunction lateral double diffused MOSFET (SJ-LDMOS). When the drift region is fully depleted, charge compensation occurs as follows: N-pillar depletion charges compensate with P-pillar depletion charges in most of the drift region, and the charges introduced by the VLD and LDR compensate with the opposite increasing substrate charges to overcome the substrate assisted depletion (SAD) effect. Besides, the LDR applied under the drain electrode can also reduce the curvature effect of the shallowly implanted drain region. Meanwhile, a field plate connected to gate is utilized to decrease the electric field peak under gate. Simulated results show that a breakdown voltage (BV) of 415 V is achieved in the proposed SJ-LDMOS with a drift region length of 22 μm. Meanwhile, the specific on resistance (R
on, sp
) is 15.5 mΩ·cm
²
and the figure of merit (FOM = BV
²
/R
on, sp
) is 11.1 MW/cm
²
, which are much better than those of the prior arts at the same BV class.