A Numerical Study on Graphene Nanoribbon Heterojunction Dual-Material Gate Tunnel FET

TLDR: In this paper, a tunnel FET (TFET) combining both graphene nanoribbon (GNR) heterojunction (HJ) and gate work function (WF) engineering is studied with the numerical simulation.

Abstract: In this letter, a tunnel FET (TFET) combining both graphene nanoribbon (GNR) heterojunction (HJ) and gate work function (WF) engineering is studied with the numerical simulation. The lowest subthreshold swing is smaller than 15 mV/decade and the ON state current ( $I_{{\mathrm{\scriptscriptstyle ON}}}$ ) reaches to $1.7~\mu \text{A}$ with device width smaller than 3 nm. The tunnel width is well reduced with the dual-material gate (DMG) structure boosting the ON current. The channel with a wide energy gap ( $E_{g}$ ) GNR can effectively reduce the leakage current at OFF state when its length is 13 nm. It is found out that large WF difference between the gate and the GNR not only effectively enhances the tunneling effect but also leads to an electron quantum well hindering the regulation capability of the gate. This effect can be well reduced with large WF gate material on the top of the HJ region. The numerical simulation reveals that the GNR HJ-DMG TFET is a good candidate for low power applications.