ESD Behavior of MWCNT Interconnects—Part II: Unique Current Conduction Mechanism

High-current carrying capacity and superior thermal conductivity have made multiwall carbon nanotubes (MWCNTs) a material for next-generation interconnects. Its distinct electrical and thermal properties result in various physical phenomenon, interaction among which give rise to unique electro-thermal transport. The interaction aggravates in presence of high-electric fields, which generally occur under ESD conditions. In this paper, we present detailed investigation of electro-thermal transport through MWCNTs under ESD conditions. The role of the substrate, MWCNT shells, and sub-bands in ESD current conduction is highlighted, while considering two device architectures-suspended and dielectric-supported MWCNTs. The quantum electron-phonon transport under non-equilibrium (ESD) conditions is explained using CNT band structure and interplay between electrical and thermal transport along the nanotube. The investigation highlights the role of the dielectric substrate in mitigating the detrimental effects of ESD stress. A strong dependence of failure current on metal-MWCNT contact resistance is revealed. The overall breakdown mechanism is found to follow Wunsch-Bell model, indicating a direct scaling between the rate of oxidation of MWCNT shells and injected power.