Influence of post-annealing on the properties of Ta-doped In2O3 transparent conductive films

Ta-doped In2O3 transparent conductive oxide films were deposited on glass substrates using radio-frequency (RF) sputtering at 300A degrees C. The influence of post-annealing on the structural, morphologic, electrical and optical properties of the films was investigated using X-ray diffraction, field emission scanning electron microscopy, Hall measurements and optical transmission spectroscopy. The obtained films were polycrystalline with a cubic structure and were preferentially oriented in the (222) crystallographic direction. The lowest resistivity, 5.1x10(-4) Omega cm, was obtained in the film annealed at 500A degrees C, which is half of that of the un-annealed film (9.9x10(-4) Omega cm). The average optical transmittance of the films was over 90%. The optical bandgap was found to decrease with increasing annealing temperature.