Effects of post-rapid thermal annealing on structural, electrical and optical properties of hydrogenated aluminum doped zinc oxide thin films

Abstract

In this study, hydrogenated aluminum doped zinc oxide (HAZO) thin films were prepared by DC magnetron sputtering in different H2/(Ar+H2) volume ratio atmosphere. The effects of post-rapid thermal annealing (RTA) in Ar+8 % H2 atmosphere on the structural, optical, and electrical properties of the thin films were investigated systematically. Results showed that the RTA treatment effectively improved the electrical conductivity of the HAZO thin films with small hydrogen content, due to the increase of the Hall mobility and the carrier concentration. The lowest resistivity of the HAZO thin film deposited in 8 % H2 ratio atmosphere reached 6.3 × 10−4 Ω cm after RTA. The improved electrical properties of the RTA-treated HAZO films were ascribed to the activation of Al dopants, the increase of oxygen vacancies and the desorption of negative charged oxygen species at the grain. These results implied that RTA process might be useful to fabricate high quality HAZO films with a low thermal budget.