Effects of Contact Placement and Intra/Interlayer Interaction in Current Distribution of Black Phosphorus Sub-10-nm FET
Black phosphorus (BP) has been proposed as the channel material in the next generation ultrascaled CMOS devices. In order to gain insight into the current characteristics in 2-D layered materials, the current distribution of a few-layer BP Schottky barrier FET is investigated via state-of-the-art quantum device simulations. Approximately 40% of the total current was found to be concentrated in the top layer when the device was switched on, with the remaining current distributed among the other layers. In comparison, ~80% of the current concentrated below the surface in a Si device with the same structure. These features are related to the strength of the intra/interlayer interaction in few-layer BP and are unique to 2-D layered materials. Moreover, the current distribution and the device performance were different for the top- and side-contacted devices, with the side-contacted devices yielding lower resistance compared with the top-contacted devices.