Optical properties of ITO/AlOx thin films prepared by reactive d.c. magnetron sputtering

ITO/AlOx films were deposited on PMMA by reactive d.c. magnetron sputtering. A transparent AlOx film was selected as a antireflective coating material in this investigation. The feasibility of using AlOx as an antireflective coating material for ITO films, and the influence of oxygen flow rate and bias voltage on the optical properties of AlOx films were studied. A dramatic increase in absorption was observed near a wavelength of 380 nm. The absorption of ITO/AlOx films increased initially with the bias voltage. However when the bias voltage exceed a critical value, the absorption decreased again. There was a close relationship between the content of Al and the IR absorption of ITO/AlOx films. The absorption in the infrared region of ITO/AlOx films increased with the oxygen flow rate and film thickness.