Studies of two-dimensional MoS2 on enhancing the electrical performance of ultrathin copper films

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.