Unleashing the Power of 2D MoS₂: In Situ TEM Study of Its Potential as Diffusion Barriers in Ru Interconnects

This study presents the utilization of MoS₂ as a diffusion barrier for metal interconnects, in situ transmission electron microscopy (TEM) observations are employed for comprehensive understanding. The diffusion-blocking ability of MoS₂ is discussed by the diffusion and phase transformation between Ru and Si via TEM diffraction and imaging. When the sample is heated to a high temperature such that MoS₂ loses the ability to block the diffusion, Si diffuses through the MoS₂ into the Ru layer, leading to the formation of Ru₂Si₃. Both multilayer and monolayer (1L) MoS₂ exhibit exceptional diffusion-blocking ability up to 800 °C. Furthermore, plasma-treated 1L-MoS₂ shows a slightly low diffusion-blocking temperature of 750 °C, while the dangling bonds in MoS₂ improve the interfacial adhesion. These findings suggest that MoS₂ holds great potential as a diffusion barrier for metal interconnects.