New structure of tunneling carbon nanotube FET with electrical junction in part of drain region and step impurity distribution pattern

Abstract

In this paper, by using electrical junction in part of drain region which includes stepwise doping distribution, a new structure is proposed for tunneling carbon nanotube field-effect transistors (T-CNTFETs). The modified device consists of two parts in the drain region, a region without electrical junction and a region having an electrical junction where the n-type impurity is entered stepwise along the drain region. Electronic features of the modified device are simulated by the simultaneous solution of both Schrodinger and Poisson equations in self-consistent routine. Simulation consequences demonstrate that the proposed modifications reduce OFF state current and enhance the ON/OFF ratio in comparison with the conventional structures. Moreover, delay time, the product of delay and power, and subthreshold slope as important features of the T-CNTFET are enhanced. Also, to more assessment of the suggested structure, variations of cut-off frequency parameters, including transconductance and gate capacitance have been investigated.