Fundamentals of Low-Resistive 2D-Semiconductor Metal Contacts: An Ab-initio NEGF Study

Abstract Metal contacts form one of the main limitations for the introduction of 2D materials in next-generation scaled devices. Through ab-initio simulation techniques, we shed light on the fundamental physics and screen several 2D and 3D top and side contacts metals. Our findings highlight that a low semiconducting-metal contact resistance can be achieved. By selecting an appropriate 2D metal, we demonstrate both ohmic or small Schottky barrier top and side contacts. This leads to low contact resistance and good device drive performance, provided the doping concentration is sufficiently high. Additionally, we show that this doping concentration can be achieved through electrostatic doping with a gate. Finally, we perform a screening of possible 2D-3D top contacts. Finding an ohmic 2D-3D contact without a Schottky barrier has proven difficult, but it is shown that for the case of intermediate interaction strength and a limited Schottky barrier, low contact resistances can be achieved.