Analysis of propagation delay and power with variation in driver size and number of shells in multi walled carbon nanotube interconnects

Purpose: The purpose of this paper is to analyze the effect of driver size and number of shells on propagation delay and power for multi-walled carbon nanotubes (MWCNT) interconnects at 22 nm technology node. Design/methodology/approach: An equivalent circuit model of MWCNT is used for estimation and analysis of propagation delay and power. The delay and power through MWCNT and Cu interconnects are compared for various driver sizes and number of MWCNT shells. Findings: The SPICE simulation results show that the MWCNT interconnect has lower propagation delay than Cu interconnects. The delay ratio of MWCNT to Cu decreases with increase in length for different driver size and number of MWCNT shells. However, the delay ratio increases with reduction in number of MWCNT shells. The ratio of average power consumption (MWCNT/Cu) also decreases with the variation in driver size and numbers of shells with respect to the length of interconnect. The theoretical study proves CNTs to be better alternatives against copper on the ground of performance parameters. Research limitations/implications: Several challenges remain to be overcome in the areas of fabrication and process integration for CNTs. Lowering of metal nanotube contact resistance would be vital, especially for local interconnect and via applications. Moreover, rigorous characterization and modeling of electromagnetic interactions in CNT bundles; 3-D (metal) to 1-D (CNT) contact resistance; impact of defects on electrical and thermal properties; and high-frequency effects are being seen as additional challenges. Originality/value: This paper investigates, assesses and compares the performance of carbon nanotubes (CNT) based interconnects as prospective alternatives to copper wire interconnects in future VLSI chips. Multi walled CNTs assure for long/global interconnect applications.