Stability of Al doped ZnO thin film formed under different RF power and atmosphere

Aluminum doped ZnO (AZO) thin films were deposited on glass substrates by using RF magnetron sputtering annealed under hydrogen atmosphere. The investigations were measured as functions of RF power, which varied in the range from 25 to 140 W. The lowest sheet resistance of 20 ohm/sq was obtained at sputtering power of 140 W. In X-ray diffraction analysis, all films have hexagonal wurtzite crystal structure with different preferable orientation. (110) peak appeared and the intensity increased with increasing RF power. The better environmental stability was found in AZO film prepared using high RF power. The most stable film was obtained when the film was annealed at high temperature in vacuum atmosphere. Investigation of the micro-effects of re-sputtering due to negative ion bombardment of growing thin films was also observed by FESEM. All property of the AZO thin film makes it suitable for transparent conductive electrode applications.