Enhancement of Tunneling CNTFET Performance Using a High-k Dielectric Pocket

Abstract

The Tunneling Carbon Nanotube FET (T-CNTFET) is one of the most promising alternatives to the conventional MOSFET. However, T-CNTFET suffers mainly from low ON-current. In this paper, we propose a modified hetero-dielectric T-CNTFET in which a dielectric pocket is inserted near the source-channel interface. The impact of the length of the dielectric pocket and its shift from source/channel barrier on DC and high-frequency performance is investigated. The performance parameters are studied by examining ON-current (I ON) and cutoff frequency (f T ) as measures for the DC and high frequency behavior, respectively. It is demonstrated that the condition of an optimum design for the pocket position concerning I ON is different from that regarding f T and a compromise should be met in order to obtain the best performance. Based on our developed 2D quantum simulations, it is shown that a high-k pocket having a length of 12.5% of the channel length may result in an increase of 65% in I ON with no deterioration in f T . Moreover, a little shift of 20% of the pocket length towards the source region doesn’t degrade I ON and enhances f T .