Effects of hydrogen treatment and substrate temperatures on the properties of Al-doped ZnO films

Al-doped ZnO (AZO) transparent conducting films were successfully prepared on glass substrates by radio-frequency (RF) magnetron sputtering. In order to reduce the resistivity of the thin films, the AZO film was hydrogenated with the addition of H₂ in the sputtering atmosphere. The effects of hydrogen ratio in the sputtering ambient and substrate temperature on the effectiveness of hydrogen incorporation in Al-doped ZnO films were investigated. The results show that hydrogen treatment can effectively reduce the resistivity of AZO thin films at low temperatures. At the low substrate temperature of 100℃, the high-quality AZO thin films with the lowest resistivity of 6.0×10^-4 Ω·cm can be obtained by adjusting the H₂ ratio in sputtering ambient. The resistivity of AZO thin film with hydrogen incorporation is less than 1/3 compared with that of thin film without hydrogen incorporation under the same condition. Moreover, the improvement of hydrogen treatment on electrical properties is gradually weakened with the substrate temperature increasing.