Computational Investigation of Negative Capacitance Coaxially Gated Carbon Nanotube Field-Effect Transistors

In this article, we present a computational investigation on nanoscale coaxial-gate negative-capacitance carbon nanotube field-effect transistor (NC CNTFET). The proposed nanodevice is endowed with metal-ferroelectric-metal-insulator-semiconductor (MFMIS) structure. The simulation approach is based on solving self-consistently the nonequilibrium Green's function formalism with the NC FET electrostatics considering ballistic transport conditions. The computational assessment includes the switching performance and short-channel effects (SCEs) in NC CNTFETs. The negative capacitance behavior of the ferroelectric has been found efficient in boosting the performance of nanoscale CNTFETs in terms of subthreshold swing (SS), drain-induced barrier lowering (DIBL), ON-current, current ratio, and intrinsic delay. In addition, we show the capability of MFMIS configuration in improving the current ratio and SS of CNTFETs with ultrascaled gate lengths. The role of the ferroelectric layer thickness in enhancing the NC CNTFET performance is also studied, where improved performance has been recorded using thicker ferroelectric layer. Achieving high ION/IOFF current ratio, sub-kT SS, and improved immunity against SCEs makes the NC CNTFET as a potential candidate for modern CNT-based nanoelectronics.