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High frequency performance limits of graphene field-effect transistors (FETs) down to a channel length of 20 nm have been examined by using self-consistent quantum simulations. The results indicate that although Klein band-to-band tunneling is significant for sub-100 nm graphene FETs, it is possible to achieve a good transconductance and ballistic on–off ratio larger than 3 even at a channel length of 20 nm. At a channel length of 20 nm, the intrinsic cut-off frequency remains at a few THz for various gate insulator thickness values, but a thin gate insulator is necessary for a good transconductance and smaller degradation of cut-off frequency in the presence of parasitic capacitance. The intrinsic cut-off frequency is close to the LC characteristic frequency set by graphene kinetic inductance (L) and quantum capacitance (C), which is about 100 GHz·μm divided by the gate length.


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Assessment of High-Frequency Performance Limits of Graphene Field-Effect Transistors

Show Author's information Jyotsna ChauhanJing Guo( )
Department of Electrical and Computer EngineeringUniversity of FloridaGainesvilleFL 32611-6130USA

Abstract

High frequency performance limits of graphene field-effect transistors (FETs) down to a channel length of 20 nm have been examined by using self-consistent quantum simulations. The results indicate that although Klein band-to-band tunneling is significant for sub-100 nm graphene FETs, it is possible to achieve a good transconductance and ballistic on–off ratio larger than 3 even at a channel length of 20 nm. At a channel length of 20 nm, the intrinsic cut-off frequency remains at a few THz for various gate insulator thickness values, but a thin gate insulator is necessary for a good transconductance and smaller degradation of cut-off frequency in the presence of parasitic capacitance. The intrinsic cut-off frequency is close to the LC characteristic frequency set by graphene kinetic inductance (L) and quantum capacitance (C), which is about 100 GHz·μm divided by the gate length.

Keywords: carbon nanotube (CNT), Field effect transistor (FET), radio frequency (RF), intrinsic cut-off frequency, transconductance

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Publication history
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Acknowledgements

Publication history

Received: 14 December 2010
Revised: 01 February 2011
Accepted: 01 February 2011
Published: 12 March 2011
Issue date: June 2011

Copyright

© Tsinghua University Press and Springer‐Verlag Berlin Heidelberg 2011

Acknowledgements

Acknowledgements

We would like to thank Dr. Eric Snow of Naval Research Lab (NRL) for bringing this important problem to our attention, and Prof. K. Shepard and I. Meric of Columbia University for helpful discussions on Klein tunneling. This work was supported by ONR, NSF, and ARL.

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