Suppression of Ambipolar current in Tunnel Field-Effect Transistor using Field-Plate

This paper proposes a tunnel field-effect transistor (TFET) with an additional field-plate over the drain region in the device. Using 2-D device simulations, it is shown that, by introducing a field-plate with an appropriate work function, placed on the top of the drain region, the ambipolar current of the device can be effectively suppressed. Furthermore, it is demonstrated that when a field-plate is placed at an appropriate height on the drain region, the gate-to-drain capacitance of the device does not increase significantly. Using simulations, it is shown that, compared to the gate-on-drain overlap technique, the proposed technique results in a substantial decrease in the gate-to-drain capacitance. Consequently, the fan-out of four (FO4) inverter delay is 22% smaller in the circuit realized using the proposed device compared to the circuit realized using TFETs having gate-on-drain overlap.