Improving band-to-band tunneling in a tunneling carbon nanotube field effect transistor by multi-level development of impurities in the drain region
Department of Electrical Engineering, Energy Faculty, Kermanshah University of Technology, Kermanshah, Iran
2 Department of Electronics, College of Electrical Engineering, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran
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Accepted: 2 November 2017
Published online: 7 December 2017
In this paper, in order to improve the performance of a tunneling carbon nanotube field effect transistor (T-CNTFET) a new structure is proposed using multi-level impurity distribution along the drain region. The new T-CNTFET structure consists of six parts in the drain with stepwise doping distribution. The impurities on the drain side are n -type and the length of each region is 5nm. Electronic features of the proposed structure are simulated by the solution of Poisson and Schrödinger equations and the self-consistent method using Non-equilibrium Green’s Function (NEGF). Simulation results show that the proposed structure reduces the band curvature near the drain-channel connection and widens the tunneling barrier. As a result, band-to-band tunneling and the OFF current are reduced and the ON/OFF current ratio increases in comparison with the conventional structure. In summary, by improving the subthreshold swing parameters, delay time, power delay product (PDP and cut-off frequency compared to the conventional structure, the proposed structure can be considered as a proper candidate for digital applications with high speed and low power dissipation.
© Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature, 2017