Post-annealing properties of aluminum-doped zinc oxide films fabricated by ion beam co-sputtering

Abstract

Aluminum-doped zinc oxide (AZO) films were fabricated by using the ion beam sputter deposition (IBSD) method with dual metallic targets, Al and Zn, co-sputtered by argon ion beam in an oxygen ambient. Structural and electrical properties of AZO films before and after annealing were ex situ investigated by the X-ray diffractometer and Hall measurement with the Van der Pauw method, respectively. The intense (002) diffraction peak and simultaneously the low resistivity were observed in the as-deposited film. The resistivity of the film after 400 °C post-anneal increased more than two orders of magnitude than that of the as-deposited film resulting from the decrease of the donor concentration and mobility in the AZO film. The residual stress was derived from the results of the XRD patterns. Finally, it was found that the film resistivity increased as the annealing temperature increased and a corresponding shift of the energy band gap was observed.