International audienceWe studied the behavior of tungsten wires, fabricated by focused-ion-beam-induced deposition and subjected to high current density. We present a simple electrical treatment, which allows an improved wire resistivity of more than 80%. We have distinguished two steps in the treatment. When the current density reaches 1.4x107 A/cm2, Ga atoms segregate and form droplets on the wire. As the current density increases, new droplets appear and merge into a single droplet. At 5.8x107 A/cm2, the droplet evaporates, the resistance is lost and the wire crystallizes. The final resistivity is close to 55 µV cm. The same treatment applied to as-deposited platinum wires does not lead to the same observations: neither segregation nor crystallization was found

Articles you may be interested inResistivity change of the diamondlike carbon, deposited by focused-ion-beam chemical vapor deposition, induced by the annealing treatment Conductive nanowires were deposited by a focused gallium ion beam using W͑CO͒ 6 and ͑CH 3 ͒ 3 CH 3 C 5 H 4 Pt as precursors. An in situ electrical treatment can substantially modify the structure and resistivity of these nanowires. This treatment consists in applying voltage ramps to the wire, leading to a high current density that induces wire annealing. The nanowires are deposited by focused ion-beam-induced deposition on two kinds of customized supports based on diamondlike carbon or Si 3 N 4 membranes, particularly suitable for electrical tests and transmission electron microscopy characterization. In the case of tungsten wires, the treatment induces an improvement of the resistivity due to both gallium contamination removal and wire crystallization, which occurs at high temperature. The treatment leads to low-resistivity ͑50 ⍀ cm͒ polycrystalline tungsten nanowires. For platinum wires, the treatment induces an increase of resistivity. In fact, this treated wire was composed of conductive droplets ͑platinum and PtGa 2 ͒ connected by a wire with poor conductivity.

No abstract

This letter reports the monitoring of reversible displacement of a gallium droplet on a tungsten submicron wire deposited by focused ion beam from tungsten hexacarbonyl precursor. We demonstrate that by applying a voltage to the wire terminals, the internal electric field created along the wire produces the motion of the droplet. Since the matter involved in this displacement is conductive, we show that it is possible to build a submicron electrical switch. Contact can be switched on and off between two electrodes separated by a submicron gap, by electrical monitoring the position of the conductive droplet.