Performance analysis of MCB-based VLSI interconnects depending on scattering induced by substrate surface roughness

Abstract

An equivalent single-conductor model is developed for all possible structures of mixed carbon nanotube bundle interconnects at the 14-nm technology node. The results are analyzed by including the effect of scattering caused by the surface roughness of the dielectric substrate material in the temperature range from 300 to 500 K. Widely used dielectrics such as silicon dioxide (SiO2), boron nitride (BN), and silicon carbide (SiC) are compared with respect to their mean free path due to surface roughness scattering. The dynamic and functional crosstalk-induced delay, crosstalk-induced noise area, and frequency spectra of all the structures of mixed CNT bundles (MCB) are analyzed, including the effect of scattering caused by substrate surface roughness, over the complete temperature range from 300 to 500 K. The results reveal that MCB structure 4 (S4) on the SiC substrate outperforms all the other structures built on the other dielectric materials. Also, the results for S4 show a fourfold higher crosstalk-induced delay when built on each substrate material, viz. BN, SiO2, and SiC, as compared with a smooth surface over the complete range of temperature from 300 to 500 K. The crosstalk-induced noise area (CINA) for structure S4 is almost five times higher on the investigated substrate materials (BN, SiO2, and SiC) compared with a smooth surface. Moreover, the bandwidth of S4 on SiC (S4 SiC) is found to be greater than on the other substrate materials (SiO2 and BN) under the dynamic signal switching condition.