Study of channel length and thickness scaling of omega gate nanowire FETs

Omega gate nanowire FETs are simulated for various device dimensions and the effects of such scaling on threshold voltage as well as on subthreshold slope are studied. Fast Uncoupled Mode Space approach along with effective mass approximation is used to study the device characteristics. A new parameter called the “omega factor” is introduced to characterize the device performances of the omega gate FETs for different coverage of gate circumference. It is found that the variation of V_th as well as the subthreshold slope is negligible with channel length variation. However, the variations in the aforementioned parameters were quite prominent with channel thickness variation. Finally, a minimum channel thickness was devised for which the threshold voltage becomes negative that poses a lower limit on scaling of such devices.