On the Ballistic Performance of InGaSb XOI FET: Impact of Channel Thickness and Interface States

Here, we report the effect of channel thickness on the performance of a InGaSb-on-insulator FET with 15-nm gate length. The ballistic current-voltage characteristic is computed by nonequilibrium Green´s function method using thickness-dependent effective mass, which is extracted from tight binding dispersion. Simulation result reveals that the threshold voltage and subthreshold slope decrease with decreasing channel thickness. Nearly three times enhancement in the ON-state current is observed for 3 nm compared with a 5-nm channel when the OFF-state current is made equal in each case by tuning the gate metal work function (WF). The drain-induced barrier lowering is found to decrease with decreasing channel thickness. However, interface states and roughness greatly affect the performance of such ultrathin-body device. Nevertheless, impact of interface states can be compensated by engineering the gate metal WF.