Low Resistive Edge Contacts to CVD‐Grown Graphene Using a CMOS Compatible Metal

The exploitation of the excellent intrinsic electronic properties of graphene for device applications is hampered by a large contact resistancebetween the metal and graphene. The formation of edge contacts rather than top contacts is one of the most promising solutions for realizing low ohmic contacts. In this paper the fabrication and characterization of edge contacts to large area CVD-grown monolayer graphene by means of optical lithography using CMOS compatible metals, i.e. Nickel and Aluminum is reported. Extraction of the contact resistanceby Transfer LineMethod (TLM) as well as the direct measurement using Kelvin Probe Force Microscopy demonstrates a very low width specific contact resistancedown to 130 Ωμm. The contact resistanceis found to be stable for annealing temperatures up to 150°C enabling further device processing. Using this contact scheme for edge contacts, a field effect transistor based on CVD graphene with a high transconductance of 0.63 mS/μm at 1 V bias voltage is fabricated.