Bilayer Graphene/Copper Hybrid On-Chip Interconnect: A Reliability Study

In this paper, we investigate key reliability limiting factors of bilayer graphene (BLG)/copper hybrid interconnect system by examining its current-induced breakdown behavior and BLG/Cu contact. The results show that BLG displays an impressive current-carrying capacity (~100 times that of Cu), and dc current-induced thermal annealing helps to significantly reduce the BLG/Cu contact resistance. Breakdown occurs with two different failure modes depending on stressing current density in each material subsystem, while contact damage dominates in scaled structure. The observed linear dependence of breakdown current on graphene geometry aspect ratio suggests Joule heating as the primary breakdown mechanism in graphene.