Patterned Electrochemical Deposition through Local Heating of Electrodes

The ability to control the rate and nature of electrochemical deposition at different locations on a single electrode could enable pattern generation and the formation of functional structures with dimensions that are smaller than the electrodes themselves. Here we explore the kinetics of this effect by incorporating a heater beneath an electrode to increase the deposition rate locally. For galvanostatic copper deposition from acidified copper sulphate, we perform deposition in a liquid cell in the transmission electron microscope to measure the deposited thickness as a function of time. We show that the Cu deposition rate can double for a temperature rise of 20 °C, but the enhancement occurs only at early times, after which the growth rate converges to the unheated value. We model the factors responsible for the enhancement and conclude that the excess material deposited is limited by diffusion. We discuss opportunities for deposition patterned in this way to control thickness, composition or structure.