P as the Optimal Inhibitor for Suppressing Surface Electromigration and Electrical Breakdown at the Source

Based on an extensive search across the periodic table utilizing first-principles density functional theory, we discover phosphorus to be an optimal surface electromigration inhibitor on the technologically important Cu(111) surface-the dominant diffusion pathway in modern nanoelectronics interconnects. Unrecognized thus far, such an inhibitor is characterized by energetically favoring (and binding strongly at) the kink sites of step edges. These properties are determined to generally reside in elements that form strong covalent bonds with substrate metal atoms. This finding sheds new light on the possibility of halting surface electromigration via kink blocking impurities.