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.
