Use of spectroscopic ellipsometry to study Zr/Ti films on Al

Spectroscopic ellipsometry in the spectral range between the near‐ultraviolet and the near‐infrared (250–1700 nm) (SE) and the mid‐infrared (2–23 µm) (IR‐SE) have been used for the characterization of various thin coatings on aluminium. Both SE and IR‐SE provide information concerning the morphological features of the coating, but owing to the presence of characteristic absorptions IR‐SE also reveals the chemical composition. This paper discusses the application of the developed optical models for the characterization of the more complex Zr/Ti‐based passivation coatings. The results obtained indicate that these coatings consist of a complex hydrated Zr/Ti/Al oxyfluoride. Copyright © 2002 John Wiley & Sons, Ltd.