The use of a Gaussian doping distribution in the channel region to improve the performance of a tunneling carbon nanotube field-effect transistor

A new structure with a Gaussian doping distribution along the channel region is proposed to improve the performance of tunneling carbon nanotube field-effect transistors (T-CNTFETs). The new structure involves a Gaussian doping distribution in the channel region with a low level of doping at the sides that gradually increases towards the middle of the channel. The source doping is p-type, while the doping in the drain and channel regions is n-type. The doping distribution is uniform in the drain/source regions. To simulate the behavior of T-CNTFETs, the Poisson and Schrödinger equations are solved self-consistently using the nonequilibrium Green’s function formalism. The simulation results show that the proposed structure exhibits increased saturation current but decreased OFF-state current compared with the conventional structure (C-T-CNTFET), yielding a ~ 104 times higher current ratio for a gate length of 20 nm. The proposed structure also shows improvements in parameters such as the transconductance, gate capacitance, cutoff frequency, and delay compared with the conventional structure and can be considered to be a more appropriate option for different applications.