Study of the current on/off ratio of an Indium Arsenide circular nanowire transistor using non-equilibrium green's function approach

Abstract

The effect of gate dielectric material, channel length, thickness of gate oxide and the diameter of the channel on the on/off current ratio of a circular nanowire channel field effect transistor with channel material Indium Arsenide is theoretically investigated in this paper. Schrodinger's equation and Poisson's equation were solved self-consistently to produce comparative simulation results. From the study of dielectric materials, it was observed that even though the off current remains the same, the on-current increases from 2.3μA to 4.33μA when we use materials of κ value 20 instead of the most used SiO 2 which has κ value of 3.9. It was also found that with increasing thickness oxide, the on current increases but there is also significant drop in the off current. On the other hand, we observe that on/off current ratio is almost independent of channel length till 10nm. As we go below 10nm in channel length, the off current starts increasing causing the current on/off ratio to fall slightly. The slight decrease of the on-off ratio was found to be quite minimal. Finally, the effect of channel diameter on current on/off ratio was studied. It was seen that smaller the diameter, the better the current on-off ratio is.