Loss in discharging atoms through artificial hole for fabricating metallic micro/nanowire by electromigration

Abstract

The electromigration (EM) technique is a method that is used to ensure the physical growth of metallic micro/nanowires. In the EM technique, the atomic diffusion of metals is intentionally accelerated by controlling the input current and heating the substrate, thus forming a hillock owing to the accumulation of atoms, which is transformed into small-diameter metallic micro/nanowires. The metallic micro/nanowires can be fabricated by discharging the atoms through a hole, which is artificially introduced in the passivation. The fabrication of metallic micro/nanowires has been successfully demonstrated using the EM technique, and the wire growth behavior is dependent on the characteristics of the artificial hole. However, very little information is available about the quantitative assessment of wire fabrication performance even though several experimental attempts have been conducted in prior studies. Additionally, the effect of structural parameters, such as the hole size, on the fabrication performance has not yet been adequately investigated. This study quantitatively evaluates the fabrication performance that is influenced by the hole size in terms of the growth rate of wires and threshold current used for fabrication. Based on the experimental results, the fabrication loss related to the hole size is experimentally revealed; further, an empirical formula for the fabrication loss has been developed. The optimal hole size to achieve the high performance of the micro/nanowire growth using the EM technique can be obtained with this finding.