Metal-to-Multilayer-Graphene Contact—Part II: Analysis of Contact Resistance

Abstract

The parasitic contact resistance between metal electrodes and multilayer graphene (MLG) is studied, and the different parameters influencing the contact resistance are investigated. A theoretical model that was developed in the companion paper is applied to typical metal–MLG structures to study the characteristics of the contact. The contributions of all of the three major components of resistance—the top and edge contacts (side and end contacts), the MLG sheet resistivity, and the metal sheet resistivity—to the total resistance are studied. The results show that the total resistance of the metal–MLG contact reduces substantially with the incorporation of edge contacts as the number of graphene layers increases. The current crowding effects are studied with and without consideration of the metal resistivity. Furthermore, the conditions where each of the three major resistance components becomes important are investigated. It is shown that the metal resistance can play an important role in determining the total resistance and current distribution in the contact. The developed model can be used in the characterization and in the design of efficient metal–MLG contact structures. It is shown that, due to the presence of edge contacts, the conventional methods of contact characterization cannot model the metal–MLG structure accurately.