Nanotube Tunneling FET With a Core Source for Ultrasteep Subthreshold Swing: A Simulation Study

In this article, we propose a novel nanotube (NT) tunneling field-effect transistor with a core source (CSNT-TFET) which uses line tunneling. We systematically investigate the CSNT-TFET with the help of calibrated 3-D simulations and demonstrate that it outperforms the conventional NT-TFET in terms of both static and dynamic performance. We show that the CSNT-TFET exhibits a reduced average subthreshold swing (SS) of 33 mV/decade with Ge-source for more than eight orders of magnitude of drain current at an ultralow supply voltage (VDS = 0.3 V). In addition, the ON-state current of the CSNT-TFET is enhanced by ~13 times with Si-source and by ~6 times with Ge-source even at V
_DS
= V
_GS
= 0.3 V when compared with the NT-TFET. Without the use of any exotic material for the source and channel regions, the CSNT-TFET offers an impact ionization MOS-like steep SS (a minimum SSpoint of ~1 mV/decade) and a high ON-state current of ~ 10
^-6
A for V
_DS
= V
_GS
= 0.3 V. Furthermore, the impact of the gate sidewall spacer and source diameter on the performance of the CSNT-TFET is also investigated.