Cp. Auth et Jd. Plummer, A SIMPLE-MODEL FOR THRESHOLD VOLTAGE OF SURROUNDING-GATE MOSFETS, I.E.E.E. transactions on electron devices, 45(11), 1998, pp. 2381-2383
We propose a threshold voltage model for surrounding-gate MOSFET's, Th
e model treats the ends and the double-gate regions of the channel as
separate devices operating in parallel. The threshold voltage for the
full device is obtained as the perimeter-weighted sum of the threshold
voltages of the two parts enabling simple analytic threshold models t
o be used, Short channel effects and drain-induced barrier towering ar
e also modeled in this manner.