Toward near-bulk resistivity of Cu for next-generation nano-interconnects: Graphene-coated Cu

Abstract

Recently, graphene has attracted much attention as a promising barrier material for Cu interconnection electrodes because of its excellent electrical, thermal, and mechanical properties and its ability to prevent the diffusion of Cu atoms. However, the effects of graphene on the electrical resistivity of graphene encapsulated Cu are still not fully understood. Here, we investigate the mechanism of electrical conduction in thin Cu films in contact with graphene. The contact of Cu with graphene layers was found to significantly reduce the resistivity of Cu thin films because it provides new current paths near highly resistive Cu grain boundaries. This effect became more prominent as charge-carrier mobility of graphene increased. In addition, we demonstrate that graphene encapsulation without performing any Cu engineering can ideally reduce the resistivity of Cu thin films by > 40%. The presence of graphene also significantly improves the stability of the electrical resistance of Cu thin films during bending.