Improved performance of nanoscale junctionless carbon nanotube tunneling FETs using dual-material source gate design: A quantum simulation study

Abstract

This paper proposes a novel technique based on dual-material source gate (DMSG) design to enhance the performance of a junctionless carbon nanotube tunneling field-effect transistor (JL CNTTFET) endowed with ultrascaled coaxial gate. The nanodevice is computationally investigated by quantum transport simulations, which treat the ballistic transport via the non-equilibrium Green's function (NEGF) formalism while considering the self-consistent nanodevice electrostatics. The dual-material source gate design aims to reduce the ultrascaled gate effects on the performance of the CNTTFET while maintaining the junctionless benefits. It has been found that the engineered source-gate work function based on the dual-material strategy can greatly improve the performance of the JL CNTTFET with 5-nm coaxial-gate length, namely the subthreshold and switching characteristics. The record of steeper swing factor, high current ratio, and enhanced ambipolar and leakage current in an ultrascaled regime has explicitly confirmed the efficacy of the proposed DMSG-based improvement technique while making it a promising and viable technique for high-performance ultrascaled junctionless tunnel nanotransistors.