Dependability Assessment of Transfer Length Method to Extract the Metal–Graphene Contact Resistance

The measurement of the contact resistance (RC) in semiconductor devices relies on the well–established Transfer Length Method (TLM). However, an in–depth investigation on its applicability to characterize the metal–graphene contacts is still missing. In this work, a dependability analysis on the RC values extracted from several metal–graphene stacks is performed, also devising strategies to limit the large observed statistical errors and to obtain dependable results. In particular, artifacts due to an incorrect application of TLM, e.g., negative resistance values, can be eliminated. Finally, a simulation study is proposed to quantify the contribution to RC of the so–called junction resistance at the edge of the contact, that some authors in the literature invoke to explain the observed artifacts.