Electrochemical polishing of ITO films

Oxalic acid and tartaric acid were used to electrochemically treat the surface of indium tin oxide (ITO) films. To improve the surface of ITO films, the applied voltage was found via potentiodynamic technique. By controlling the concentration of oxalic acid and tartaric acid, the surface can be effectively planarized via the formation of a passive layer. The composition of this passive layer might be SnO2 according to XPS analysis and potential–pH diagrams. The best treatment with root-mean-squared roughness less than 1.0 nm can be obtained by electropolishing at 0.65 V in 3 wt% tartaric acid.