  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 model, we obtained the specularity parameter at
the Cu MoS2 interface in the temperature range 2K to 300K. Furthermore, first
principle calculations based on the density functional theory 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.
