Transparent and conductive tin-doped indium oxide (ITO) films have been prepared by rf sputtering in an Ar and Ar+O2 gas mixture, both with and without additional substrate heating. The influence of both deposition conditions and post-annealing treatment on optical, electrical, structural and microstructural properties of the ITO films has been investigated. The optical constants have been calculated in the range 320–2500 nm using a combination of several theoretical models.
A schematic diagram for the film properties change versus composition has been proposed in terms of a generalized parameter characterising the energy efficiency of the film formation. The deposition conditions and the optical and electrical properties of the films have been optimized with respect to the requirements for their application in art protection coatings.