Atypical characteristics of KrF excimer laser ablation of indium-tin oxide films

Indium-tin oxide films possess ablation characteristics which are a function of the film thickness. For 70 and 160 nm thicknesses, low-fluence single pulses are sufficient to remove from the support the solid phase oxide film over the whole illuminated area. Processing under such conditions offers a rather convenient means for large-area “clean” surface patterning, which is, however, limited at high fluences by the onset of melting. At fluences higher than this onset, layer-by-layer ablation via evaporation sets in. For thicker films, only ablation via evaporation is possible. These experimental findings are interpreted in the framework of a thermal model which is supported by appropriate numerical calculations of the temperature distribution in these films.