High-Performance Carbon Nanotube Field-Effect Transistor with Tunable Polarities

TL;DR

This paper introduces a novel CNFET design that achieves high performance and tunable polarity, overcoming traditional limitations of ambipolar behavior and leakage currents, enabling aggressive scaling.

Contribution

The authors present a new device concept for CNFETs that allows for electrostatic and chemical doping to achieve unipolar behavior with excellent OFF-state performance.

Findings

Achieved enhancement-mode operation with n or p-type unipolar behavior.

Demonstrated steep subthreshold swing of 63 mV/dec.

Maintained device performance with aggressive oxide and gate length scaling.

Abstract

State-of-the-art carbon nanotube field-effect transistors (CNFETs) behave as Schottky barrier (SB)-modulated transistors. It is known that vertical scaling of the gate oxide significantly improves the performance of these devices. However, decreasing the oxide thickness also results in pronounced ambipolar transistor characteristics and increased drain leakage currents. Using a novel device concept, we have fabricated high-performance, enhancement-mode CNFETs exhibiting n or p-type unipolar behavior, tunable by electrostatic and/or chemical doping, with excellent OFF-state performance and a steep subthreshold swing (S =63 mV/dec). The device design allows for aggressive oxide thickness and gate length scaling while maintaining the desired device characteristics.