Kinematics and Kinetics of Alternating Electric Field Induced Liquid Mass Transport on Chromium Thin Films.

Long range mass transport, driven by electric field, has myriad applications in the field of nano science and technology. On Chromium (Cr) thin film, liquid phase mass transport ranging from micrometer to millimeter scale and its application to nanopatterning have been demonstrated using DC electric field. Under the influence of electric field, the metal seems to undergo a chemical reaction and the resulting liquid material flows out radially in all directions. In this study, we have explored the effect of alternating (AC) electric field on this kind of liquid phase material transport. Within the scope of this work, mass transport has been studied on 30 nm thick Cr films with an alternating square waveform having frequency in the range of 100 Hz to 1000 Hz in steps of 50 Hz. The dependence of frequency for a constant applied root mean square (RMS) voltage on the material formation, flow distance and flow velocity are studied in detail. An analytical model has been presented to explain the experimental results. This study, especially the frequency parameter and the intermittent nature of the applied bias, will help us in getting a better control over the mass flow process, which will lead to better resolution for the electrolithography technique.