High-throughput nanogap formation by field-emission-induced electromigration

Abstract

High-throughput nanogap formation is reported for simultaneous fabrication of integrated nanogap arrays. Ten series-connected nanogaps with butterfly and bottle shapes were integrated by using electromigration induced by a field emission current (“activation”). Initially, ten series-connected butterfly-shaped nickel (Ni) nanogaps were fabricated with electron-beam lithography and lift-off processes. Activation with a preset current of 300 nA reduced the separation of the gaps to <10 nm. Similar results for bottle-shaped nanogaps indicated that integration of nanogaps using activation is not dependent on nanogap shape. The activation method was also used for the mass production of 30 identical nanogaps. Overall, the distance between the Ni nanogap electrodes was completely controlled by activation.

Gold nanogap-based artificial synapses

“…22) In a previous study, we developed a simple technique for the fabrication of nanogaps with well-controlled tunnel resistance called "activation." [23][24][25][26][27][28][29][30] This method is based on electromigration (EM) induced by a Fowler-Nordheim (F-N) field emission current. The activation scheme controls the tunnel resistance of the nanogaps by adjusting the magnitude of the field emission current.…”

Fabrication of a Horizontal and a Vertical Large Surface Area Nanogap Electrochemical Sensor

“…Early forms of nanogaps were predominantly horizontal coplanar devices and a range of fabrication techniques exist, including: electron-beam lithography (EBL) [1,2], mechanical break junctions [3], focused ion beam (FIB) milling [4,5], oxidative plasma ablation [6], electromigration [7,8], electroplating [9], molecular rulers [10], chemical-mechanical polishing (CMP) [11] electrochemical synthesis [12], direct chemical synthesis [13], and dip-pen nanolithography (DPN) [14]. …”