Thermally Aware Modeling and Analysis of Mixed CNT for Future Nanoscale Technology Nodes

Abstract

With the upgrades in technology, the number of functionalities is escalating on advanced integrated chips. In this trend, the number of global interconnects that helps to join these circuit chips is also increasing. Global interconnects are long interconnects that run globally across the chip and help to associate global signals like a clock, power, and round to all modules. In this way, the parasite associated with longer interconnects increases, and ultimately the performance of interconnects is degraded at scaled nodes. So, an indispensable need of the hour demands a suitable material that can be employed for interconnect applications in the coming times. Carbon nanotubes have been advised as the best alternative to copper interconnects, which suffered from electromigration, grain boundary scattering, and surface roughness after 45nm technology node. Because carbon nanotubes possess notably good electrical, mechanical, and thermal properties, they can easily oust copper for interconnect applications. Formed with the layer of carbon in the form of graphite and rolled up in a cylindrical shape, carbon nanotubes are classified into single-walled carbon nanotubes (single layer of graphite), multi-walled carbon nanotubes (multiple layers of graphite rolled concentrically) and double-walled carbon nanotube (two layers of graphite rolled concentrically). Since a single carbon nanotube offers a high value of resistance, the bundle of interconnect is made by placing nanotubes parallelly in the bundle. Interconnects can be well presented by transmission lines with distributed impedance parameters and are driven by CMOS transistors (using the alpha-power law model). A quick and concise comparative analysis has been done between copper and carbon nanotubes to determine impedance parameters, propagation delay, power dissipation, and power-delay product. It has been analyzed that carbon nanotubes offer better performance than copper at global lengths. The present work focuses on a new mixed class of carbon nanotubes which