Presented for the first time is an accurate modelling hierarchy for mixed CNT bundle interconnects. Single-walled CNTs and multi-walled CNTs have been modelled as equivalent single conductor transmission lines and then combined to form a mixed CNT bundle interconnect, which is basically a multiple equivalent single conductor model. Two multiple equivalent single conductor interconnects have been taken to form the multiconductor transmission line model. The delays from transient analysis for both models for a unit bundle have been compared with the corresponding ones for SWCNT bundles and MWCNTs that exist in the literature. It is found that mixed CNT bundle interconnects are superior to both SWCNT bundle and MWCNT interconnects in terms of delay.

This article presents a realistic inter-carbon nanotube (CNT) electrostatic coupling capacitance and tunnelling conductance model for a mixed CNT bundle. The change of potential across such a bundle necessitates the need to consider the inter-CNT capacitance in the equivalent circuit of CNT interconnects for very large scale integration circuits. The equivalent transmission line circuit model of a unit bundle containing one single-walled CNT (SWCNT) and one multi-walled CNT (MWCNT) has been shown. This new model is then used to calculate the delay induced by the inter-CNT capacitance and tunnelling conductance, which predicts the relative positioning of MW/SWCNTs in mixed CNT bundle.

In this letter, we present a new method to reduce crosstalk of carbon nanotube (CNT)-based VLSI interconnects. For this, proper integration of semiconducting CNTs (s-CNTs) and a new contact geometry, where metallic CNTs are in the core and s-CNTs are in the periphery of the CNT bundle, is proposed. The coupling capacitance between adjacent interconnects is modeled and compared with and without s-CNTs in the CNT bundle periphery. SPICE analysis and EM simulations are carried out which show that the coupling capacitance can be reduced by 82.5% and the resulting delay by 8.41%. We suggest that the crosstalk effect between neighboring wires can be reduced by using s-CNTs in the design.