An accurate on-resistance model of VDMOS devices in the low voltage re
gimes is proposed and verified by numerical simulation results. The mo
del considers the lateral Gaussian doping profiles in the channel regi
on and exact current spreading angles in the epitaxial layer for both
linear and cellular geometries by employing the conformal mapping. Res
ults of the proposed model are in good agreement with those of 2D and
quasi-3D simulations obtained by PISCES-IIB for a VDMOS device with 10
0 V rating. The on-resistance of a low voltage VDMOS may be considerab
ly overestimated if it is analyzed by the conventional method.