First principles study on the early nucleation process of carbon nanotubes on Ni (1 1 1) surface

As process technology continues to evolve, the dimensions of integrated circuits are progressively diminishing, and consequently, the space designated for interconnects is likewise shrinking. Consequently, traditional copper interconnects are struggling to fulfill the growing demands, necessitating the search for alternative interconnect materials to supersede copper. Among the various prospective materials, carbon nanotubes(CNTs) have garnered considerable research focus. Nevertheless, the challenge of forming interconnects via the growth of CNTs within through-silicon vias(TSVs) through chemical vapor deposition(CVD) currently encounters hurdles pertaining to the control of CNT chirality and growth temperature. In this investigation, density functional theory(DFT) was utilized to delve into the energetics of the nascent nucleation phase of CNTs growing on Ni(1 1 1) surfaces. We examined the energetics associated with the formation of C₂ to C₄ clusters and computed the diffusion barriers for these clusters, revealing that C₃ exhibits the lowest diffusion barrier. Additionally, in our energetics calculations for the formation of C₅ and C₆ clusters, we took into account nearly all conceivable scenarios. This research holds paramount significance for elucidating the growth mechanisms of carbon nanotubes on Ni(1 1 1) surfaces during the CVD process.