Purification and crystallization of tungsten wires fabricated by focused-ion-beam-induced deposition

Abstract

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

Felling of individual freestanding nanoobjects using focused-ion-beam milling for investigations of structural and transport properties

“…For comparison, bulk tungsten has a resistivity of 5 cm at room temperature. Resistivity values from about 100 cm to 300 cm have been reported for tungsten composites grown by FIB-induced deposition [18,23,24]. The variation in the resistivity of FIB-deposited materials is a consequence of the microstructure and composition difference due to the operating parameters, such as the ionbeam current, dose, substrate material, substrate temperature, scan speed and gas flux.…”

Nanoscale Electrical Contacts Grown by Focused Ion Beam (FIB)-Induced Deposition

“…The high metal content along the full thickness explains the low resistivity of the deposits, typically ranging between 100 and 600 μΩ cm [ 43 -45 ], only 20 times higher than the bulk W resistivity, 5.6 μΩ cm. Post-annealing of these deposits by means of Joule heating was found to be effi cient to reduce a wire resistivity from 300 to 55 μΩ cm [ 46 ]. In addition to the aforementioned properties, W FIBID deposits show superconductivity below 5 K, as fi rst reported by Sadki et al [ 47 ].…”

Suspended nanowire bridge fabricated by focused ion beam as a hydrogen sensor

“…The nanowire fabrication is performed using commercially available FIB machine (SMI 3050: SEIKO Instrument Inc.). The nanowire is deposited from tungsten hexacabonyl (W(CO) 6 ) and comprises 40% atomic concentration of W, 40% of C and 20% of Ga [17].…”

“…FIB is also used to fabricate 3-dimensional nanostructures [3][4][5]. Efforts have been undertaken to investigate material properties of FIB induced nanostructures such as electrical resistivity [6], Young's modulus [7] and piezoresistivity [8]. More recently, FIB has found its usage to make electrical contact between dispersed nanowires on substrate and electrodes [9].…”