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Copper nanowires are widely used as on-chip interconnects due to superior conductivity. However, with aggressive Cu interconnect scaling, the diffusive surface scattering of electrons drastically increases the electrical resistivity. In this work, we studied the electrical performance of Cu thin films on different materials. By comparing the thickness dependence of Cu films resistivity on MoS2 and SiO2, we demonstrated that two-dimensional MoS2 can be used to enhance the electrical performance of ultrathin Cu films due to a partial specular surface scattering. By fitting the experimental data with the theoretical Fuchs-Sondheimer (FS) model, we claimed that the specularity parameter at the Cu/MoS2 interface is p ≈ 0.4 in the temperature range 1.8K < T < 300K. Furthermore, first principle calculations based on the density functional theory (DFT) indicates that there are more localized states at the Cu/amorphous SiO2 interface than the Cu/MoS2 interface which is responsible for the higher resistivity in the Cu/SiO2 heterostructure due to more severe electron scattering. Our results suggest that Cu/MoS2 hybrid is a promising candidate structure for the future generations of CMOS interconnects.

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Orientation effects on the specific resistance of copper grain boundaries are studied systematically with two different atomistic tight binding methods. A methodology is developed to model the specific resistance of grain boundaries in the ballistic limit using the Embedded Atom Model, tight binding methods and non-equilibrum Green's functions (NEGF). The methodology is validated against first principles calculations for thin films with a single coincident grain boundary, with 6.4% deviation in the specific resistance. A statistical ensemble of 600 large, random structures with grains is studied. For structures with three grains, it is found that the distribution of specific resistances is close to normal. Finally, a compact model for grain boundary specific resistance is constructed based on a neural network. * valencid@purdue.edu 1 arXiv:1701.04897v3 [cond-mat.mtrl-sci]