Dip coated ITO thin-films through sol-gel process using metal salts

Indium tin oxide (ITO) thin-films were deposited on soda-lime-silicate glass using sols prepared from alcoholic solutions of indium chloride and stannic chloride with different In:Sn atomic ratios, namely 95/5, 90/10, 85/15 and 80/20. The electrical properties, structure and morphology of the thin-films were investigated. All the films studied, with a thickness range of 10-490 nm were polycrystalline with grain sizes in the range of 25-60 nm. Uniform and dense microstructure apparently devoid of cracks and voids were observed. Only cubic In2O3 phase was observed in the X-ray diffraction (XRD) and transmission electron microscopy (TEM). SnO and SnO2 phases were not detected. The sheet resistance values decreased with increase in coating thickness. A significant decrease in the resistance values was also noted after annealing in N-2\H-2 (96-4%) atmosphere. The minimum sheet resistance values were noted for Sn concentration of 10 at.%. The lowest value, 11 ohms per square, was obtained after annealing for a 490-nm film. (C) 2001 Elsevier Science B.V. All rights reserved.