Numerical study and performance analysis of carbone nanotube field effect transistors

As transistors are scaled down to nanometers, the theory and structure of nanometers devices such as carbon nanotubes field effect transistors (CNTFET) are being extensively studied. Self consistent solution of the Poisson and Schrödinger equations is performed using the non-equilibrium Green´s function (NEGF) formalism to investigate the impact of nanotube diameter, gate oxide thickness and high-k gate dielectric permittivity parameters on the coaxially gate, n-type CNTFET. Our results show that the nanotube diameter and gate oxide thickness influences the ION/IOFF current ratio, the drain induced barrier lowering (DIBL), the subthreshold slop as well as transconductance and drain conductance. Furthermore, in this work we focus on the impact of high-k gate dielectric permittivity on the performance of CNTFETs. Using high-k dielectric is caused by the enhancement in device characteristics. A good agreement with numerical simulation results is obtained.