Analysis of subthreshold swing in multichannel tunneling carbon nanotube field effect transistor (MT-CNTFET)

Tunnel Field Effect Transistor (TFET) based on Band-to-Band tunneling mechanism is a revolutionary device technology that has a very strong potential to break the thermodynamic barrier of conventional FETs and provide a very steep subthreshold slope. However, TFETs in general suffer from low on-state current (I_ON). We propose a new TFET structure to increase the drain-to-source current of the tunneling device. The design is based on single-walled carbon nanotubes (SWCNTs). The idea is to provide multiple SWCNTs as tunneling path. We have demonstrated the concept with three SWCNTs. By having three tunneling paths in a single device higher ON current can be achieved while keeping the subthreshold swing lower than 60mV/decade. In this study, the diameter of the tubes and the gate oxide thickness are adjusted to obtain a higher I_on and steeper subthreshold slope.