Electric Current-Induced Mass Flow in Very Thin Infinite Metallic Films

Electrolithography- A New and Versatile Process for Nano Patterning

“…This corresponds to a current density of ~3.3 × 10 9 A/m 2 in the thin Cr film at a distance of 10 μm away from the probe tip. Such a flow is attributed to electromigration because (i) the observed material flow is directional (i.e., it occurs at only one of the two electrodes), (ii) directionality of the flow depends on the material (e.g., the flow occurs from the cathode probe for Cr and from the anode probe for Al), (iii) flow occurs along or in the reverse direction of the electric field lines, and (iv) the dependence of flow rate on the electric current and the temperature are linear and exponential, respectively, as predicted by the standard electromigration theory 16 17 .…”

“…Electromigration is an electric current driven, diffusion controlled material transport phenomenon that leads to formation of voids and hillocks in a solid metallic conductor near cathode and anode, respectively 18 19 . Recently, some studies on the electromigration driven flow of liquid metals over a relatively long range have also been reported 16 20 21 22 . Similar to the electromigration in solids, electromigration driven mass transport in liquid metals also varies linearly and exponentially (Arrhenius type) with the applied current density (or, electric field) and the temperature, respectively 20 22 .…”

“…In the particular case of an infinite Cr thin film deposited on an insulating substrate, the application of a high electric current using two probes situated sufficiently far away from each other (see Fig. 1a for experimental set-up) and, in the presence of air, results in liquefaction of material below the cathode, which then starts to flow in a radially symmetric fashion away from the cathode probe (Refer to Supporting Information for a video showing this phenomena) 16 . Figure 1b shows a snap-shot of the electric field induced liquid material flow in a 20 nm thick Cr film deposited on SiO 2 -Si substrate upon passing a current of density ~10 9 A/m 2 through a probe tip.…”

“…In this work, we introduce a new lithography technique that we call Electrolithography . For developing this process, we exploit as well as significantly extend our previously reported 16 17 understanding of controlled nanoscale material transport and pattern formation due to liquid electromigration in thin metal films. We apply this phenomenon to develop a scanning probe based lithography technique where liquid electromigration driven material removal is used as a key step.…”

Variable Optical Attenuator Based on Long‐Range Surface Plasmon Polariton Multimode Interference Coupler

“…However, if the thin metal waveguide is used as a heater simultaneously, when the electrical power was applied on the metal stripe, the induced temperature close to 100 ∘ C may lead to metal stripe deformation that results from the thermal expansion difference between the metal and polymer cladding and worsens when the temperature increases beyond glass transition temperature of polymer [10,15,16]. Except for the refractive index variation of the claddings surrounding the metal layer, the temperature dependent dielectric coefficient of metal may influence the mode characteristics, too [17]. Besides, a visible melting of thin metal films at the electrode may happen due to the mass flow caused by the applied direct current of high densities (>10 8 A/m 2 ) [18].…”