THERMAL HYSTERESIS OF HIGH-TEMPERATURE RESISTIVITY IN INDIUM-TIN-OXIDE FILMS

Indium-tin-oxide (ITO) films were prepared by the chemical spray pyrolysis method using InCl3.6H2O and SnCl4.xH2O (x = 3-5) as starting materials. The film with a minimum resistivity of 1.23 x 10(-3) OMEGA.cm was obtained for tin doping, Sn/In = 5 at %. Resistivity of 50 nm thick films showed hysteresis phenomena in heat cycles repeated at temperatures between 100-degrees and 500-degrees-C in O2 and Ar gases. The hysteresis results were discussed in terms of desorption of H2O from In2O3-H2O complexes, superposing desorption of adsorbed O2 from the films.