Scaling study of graphene transistors

By performing rigorous self-consistent atomistic quantum transport simulations, scaling behavior of graphene-based MOSFET and TFET are investigated. We show that phonon scattering can negatively affect the on-current and transconductance of a MOSFET significantly, and therefore on-state characteristics can be improved by reducing the channel length down to 30 nm. For a TFET, however, off-state characteristics are very susceptible to phonon scattering, and off-current can increase by 6 orders of magnitude in a 30-nm-channel TFET. In contrast to what is predicted in the ballistic picture, the minimum leakage current and subthreshold swing of a TFET do not monotonically decreased by increasing channel length, but saturate for a channel length longer than 20 nm.