Modelling of the Gate Capacitance in the Double Nanowire based Field-Effect Transistors

Nanowires (NWs) are promising candidates for high-performance flexible and printed electronics. To evaluate the performance of NW based devices, it is important to develop suitable models. To this end, this paper presents a finite element method (FEM) study of the gate capacitance from the double nanowire (NW) based field-effect transistor (FET). The influence of the diameter, NW-to-NW spacing and the relative orientation between the NWs have been evaluated. We found that the total capacitance in a sparsely distributed double NW system is dominated by the NW-to-NW spacing and their diameters; the influence of the relative orientation is almost negligible. By contrast, when the two NWs are close enough, the influence of the relative orientation starts to play a role. In the extreme case where the two NWs are in contact, the rational angle between the two NWs can influence as much as 1/3 of the total capacitance. The results from this fundamental study provide an interesting insight into the influence of NW distribution on the performance of the NW based FETs.