Design, Modeling and Analysis of Cu-Carbon Hybrid Interconnects

In this work, a new interconnect structure is proposed for the first time where copper-carbon nanotube composite interconnect is encapsulated by graphene barrier layers named here as copper-carbon (Cu-carbon) hybrid interconnects. The motivation behind this new structure is to utilize the enhanced conductivity of copper-carbon nanotube (Cu-CNT) composite and improved reliability of copper-graphene (Cu-GNR) hybrid in order to build a better interconnect structure for possible replacement of copper interconnects in near future VLSI applications. The steps required to fabricate this structure is also proposed by utilizing the fabrication methods of Cu-CNT composite and Cu-GNR hybrid materials. First-principles-based atomistic simulations suggest that Cu-Carbon hybrid structure is more conductive than its parent structures, i.e. Cu-CNT composite and Cu-GNR hybrid. This deduction is also supported by the circuit simulation results at 7 nm node which show that Cu-Carbon hybrid interconnect experiences least delay among all other alternatives. When compared to Cu-GNR, Cu-CNT and Cu interconnects, delay in 1 mm long Cu-Carbon hybrid interconnect is lesser by ~28%, ~41% and ~88%, respectively. Time-domain analysis suggests that Cu-Carbon hybrid interconnect has the steepest and sharpest step response. Cu-Carbon hybrid interconnect has proven to be superior than other alternatives in terms of signal integrity. Noise-delay-product in a 1 mm long Cu-Carbon hybrid is lesser by ~42%, ~47% and ~84% as compared to Cu-GNR, Cu-CNT and Cu interconnects, respectively. Power consumption is also least in Cu-Carbon hybrid interconnects. Power-delay-product in a 1 mm long Cu-Carbon hybrid is also reduced by ~41%, ~44% and ~43% as compared to Cu-GNR, Cu-CNT and Cu interconnects, respectively. These findings promote Cu-Carbon hybrid interconnect as a superior candidate for near future VLSI applications.