Effect of improved contact on reliability of sub-60 nm carbon nanotube vias

Advances in semiconductor technology due to the aggressive downward scaling of on-chip feature sizes have led to rapid rises in the resistivity and current density of interconnect conductors. As a result, current interconnect materials, Cu and W, are subject to performance and reliability constraints approaching or exceeding their physical limits. Therefore, alternative materials are being actively considered as potential replacements to meet such constraints. The carbon nanotube (CNT) is among the leading replacement candidates for on-chip interconnect vias due to its high aspect-ratio nanostructure and superior current-carrying capacity to Cu and W, as well as other potential candidates. Based on the results for 40 nm and 60 nm top-contact metallized CNT vias, we demonstrate that not only are their current-carrying capacities two orders of magnitude higher than their Cu and W counterparts, they are enhanced by reduced via resistance due to contact engineering facilitated by the first reported contact resistance extraction scheme for a 40 nm linewidth.