Dynamic investigation of interface atom migration during heterostructure nanojoining.

Interface atom migration and compositional evolution during the heterostructure nanojoining process under external electrical loadings has been investigated in situ inside a transmission electron microscope with atomic resolution. The results indicate that the migration of oxygen atoms on the contact interface of metal nanorods is a thermal dominated process rather than an electromigration process. After removing the oxide layer at the nanometal contact interface, the metal atoms migrate under external electrical field. The formation region of nanoalloys can be modulated by controlling the electromigration direction of nanometal atoms, leading to an electromigration-dominated cutting process which offers an extra degree of freedom to design a sacrifice layer and interconnects in solid-state bonding. These findings offer an insight of potential failure mechanisms as well as fabrication methodology for interconnects in nanodevices.