Ultra-thin reduced graphene oxide based on self-assembled monolayer for Co interconnect diffusion barrier

With the scaling of integrated circuit technology, conventional Cu interconnects face rising resistivity at reduced dimensions, driving interest in Co as an alternative. However, Co interconnects require robust diffusion barriers to mitigate ion diffusion into dielectrics. Current self-forming alloy barriers (Co-Ti or Co-Cr system) suffer from interfacial segregation and poor controllability. Here, we developed a continuous rGO/SAM composite barrier for Co interconnects. Using APTES-derived SAMs, the rGO/APTES-SAM barrier exhibited partial thermal blocking of Co diffusion at 500°C and a 12.7% electrical performance enhancement. Notably, increasing -NH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> density in SAMs significantly improved barrier effectiveness by repairing rGO lattice defects, while substituting -NH<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> with -SH showed negligible impact. This work highlights the critical role of defect-healing functional groups in optimizing graphene-based diffusion barriers.