Stress in Tin-Doped Indium Oxide Thin Films Formed on Substrates by Sputtering

Abstract

Films of tin-doped indium oxide (ITO) were prepared on silicon and soda lime glass substrates at different temperatures during sputtering. Stresses in the ITO films were measured during a uniform thermal annealing cycle in nitrogen atmosphere. A larger compressive residual stress arose in the ITO film when the substrate temperature of the film deposition was higher than that before annealing. The residual stress in the film on the silicon substrate was changed to tensile stress at room temperature after annealing when the film was formed at under the crystallization temperature of indium oxide. It was found that the consistency of low resistivity with small stress in an ITO film could be realized by high-temperature annealing after low-temperature sputtering. The surface morphology of the ITO film indicated a change in biaxial elastic modulus, which is related to thermal stress. From the results of X-ray diffraction analysis, it was suggested that the misorientation between volumes of crystals in an ITO film increased with increasing intrinsic stress.