Effect of dopants and thermal treatment on properties of Ga-Al-ZnO thin films fabricated by hetero targets sputtering system

In this study, we fabricated Ga and Al doped ZnO (Ga-Al-ZnO; GAZO) thin films by using the facing targets sputtering system under various conditions such as input current and thermal treatment temperature. The properties of the as-deposited GAZO thin films were examined by four-point, UV/Vis spectrometry, X-ray diffraction, atomic force microscopy and field-emission scanning electron microscopy. The result showed that the lowest sheet resistance of the films was 59.3ohm/sq and transmittance was about 85%. After thermal treatment, the properties of GAZO thin films were improved. The lowest sheet resistance (47.3ohm/sq) of the GAZO thin films were obtained at thermal treatment temperature of 300°C, considered to be the result of continuous substitutions by dopants and improved crystallinity by the thermal treatment. ► Ga and Al doped ZnO thin films were prepared by hetero targets sputtering system. ► Free electrons were increased due to the continuous substitutions of Ga and Al. ► Crystallinity was improved by recombination of particles with increasing of temperature.