A Numerical Study of Scaling Issues for Schottky Barrier Carbon Nanotube Transistors

TL;DR

This study uses atomistic simulations to analyze the scaling limits and design considerations of Schottky barrier carbon nanotube transistors, highlighting the effects of ambipolar conduction, channel length, and dielectric scaling.

Contribution

It provides a detailed atomistic simulation-based analysis of scaling issues in Schottky barrier CNT transistors, emphasizing the impact of device dimensions and materials.

Findings

Channel length scaling limit between 5nm and 10nm due to tunneling

Large diameter tubes increase both on-current and leakage

Charge effects on nanotube are significant above threshold

Abstract

We performed a comprehensive scaling study of Schottky barrier carbon nanotube transistors using self-consistent, atomistic scale simulations. We restrict our attention to Schottky barrier carbon nanotube FETs whose metal source/drain is attached to an intrinsic carbon nanotube channel. Ambipolar conduction is found to be an important factor that must be carefully considered in device design, especially when the gate oxide is thin. The channel length scaling limit imposed by source-drain tunneling is found to be between 5nm and 10nm, depending on the off-current specification. Using a large diameter tube increases the on-current, but it also increases the leakage current. Our study of gate dielectric scaling shows that the charge on the nanotube can play an important role above threshold.