Ultimate RF Performance Potential of Carbon Electronics

TL;DR

This paper uses simulations to show that carbon nanotube and graphene transistors can achieve RF cutoff frequencies above 1 THz, surpassing traditional semiconductors, with AFETs showing advantages in biasing and parasitic effects.

Contribution

It provides the first detailed analysis of the ultimate RF performance limits of AFETs and GFETs using ballistic transport simulations, highlighting their potential for high-frequency applications.

Findings

Both AFETs and GFETs can reach fT and fMAX above 1 THz.

AFETs are less sensitive to diameter variations and metallic tubes.

AFETs have higher ultimate cutoff frequencies and lower power dissipation.

Abstract

Carbon electronics based on carbon nanotube array field-effect transistors (AFETs) and 2-dimensional graphene field-effect transistors (GFETs) have recently attracted significant attention for potential RF applications. Here, we explore the ultimate RF performance potential for these two unique devices using semi-classical ballistic transport simulations. It is shown that the intrinsic current-gain and power-gain cutoff frequencies (fT and fMAX) above 1 THz should be possible in both AFETs and GFETs. Thus, both devices could deliver higher cut-off frequencies than traditional semiconductors such as Si and III-V's. In the case of AFETs, we show that their RF operation is not sensitive to the diameter variation of semiconducting tubes and the presence of metallic tubes in the channel. The ultimate fT and fMAX values in AFETs are observed to be higher than that in GFETs. The optimum device biasing conditions for AFETs require smaller biasing currents, and thus, lower power dissipation compared to GFETs. The degradation in high-frequency performance in the presence of external parasitics is also seen to be lower in AFETs compared to GFETs.