Intrinsic Cut-off Frequency in Scaled Graphene Transistors

TL;DR

This paper uses quantum transport simulations to analyze how short-channel effects and electrostatic considerations influence the intrinsic cut-off frequency of scaled graphene transistors, highlighting key factors for high-frequency device optimization.

Contribution

It provides a detailed simulation-based analysis of the impact of oxide thickness and electrostatics on the cut-off frequency in scaled graphene transistors, revealing non-traditional scaling behaviors.

Findings

fT scales inversely with gate length for thin oxides

Band-to-band tunneling affects fT in thick oxides

Improved electrostatics can degrade fT due to increased capacitance

Abstract

Using 2-D self-consistent ballistic quantum transport simulations, we investigate the short-channel behavior of graphene field-effect transistors and its impact on the device transconductance and subsequently the intrinsic cut-off frequency (fT). Although with thin oxides, fT expectedly scales inversely with the gate length, significant band-to-band tunneling at OFF state leads to a departure from this trend in case of thick oxides. We also examine the effect of achieving better electrostatics at the cost of increased gate capacitance and illustrate that this can indeed degrade the fT. These considerations should be implicit in the optimization of graphene transistors for high-frequency applications.