Critical Voltage for Atom Migration in Ballistic Copper Nanojunctions and Its Implications to Interconnect Technology for Very Large Scale Integrated Circuits

摘要

We investigated the critical voltage for electromigration (EM) in atomic-scale Cu nanojunctions by using EM spectroscopy. The critical voltage was determined to be 0.35 V from the peak of the obtained EM spectrum, which is close to the atom diffusion potential for clean Cu surfaces. It was also demonstrated that ballistic Cu nanojunctions can support current densities on the order of 10GA/cm~2, as long as the junctions are biased below the critical voltage. The results suggest that both high current densities and high EM reliabilities can be achieved when the dimension of the metal interconnects is reduced to several tens of atoms.