Nanoscale Smoothing in Crystallization of Amorphous Indium Tin Oxide Thin Films Induced by Glass Ultrathin Overlayer

Abstract

Nanoscale smoothing in the crystallization of amorphous indium tin oxide (ITO) thin films was achieved using an ultrathin silicate glass overlayer (about 3 nm thick). An amorphous ITO thin film with an ultrathin glass overlayer were deposited by pulsed laser ablation using the ITO ceramics and silicate glass targets, respectively. The amorphous ITO film covered by the ultrathin glass layer was crystallized by annealing at 700 °C. When the ultrathin glass layer was removed by wet etching in aqueous H3PO4, an ultrasmooth crystallized ITO film surface appeared. The surface roughness of the crystallized thin film (about 0.3 nm rms) was one order of magnitude smaller than that of the ITO films crystallized with no glass overlayer (3.1 nm rms).