Characterization of reactive sputtered ITO and TiO2/ITO thin films for applications at elevated temperatures

In this work are discussed the technology for preparing and characterisation of indium-tin oxide (ITO) and ITO with titanium oxide underlayer thin films with properties appropriate for usage at elevated temperatures as heat reflective coatings and gas sensors. For preparing the samples the methods of radio frequency (RF) and DC-magnetron reactive sputtering were used. Sputtering of indium-tin and ITO targets with different composition in presence of oxygen as reactive gas was made. The technological parameters were studied to obtain films with optimal properties at different substrates - glass, silicon, quartz. Heating of the substrates during the preparation and their postdeposition annealing in different environments also were studied. Comparison how the different techniques and target composition affect on the films' properties was made. The composition and microstructure of the films were studied by XPS, EPMA and XRD, the surface of the films was observed by a high-resolution SEM. Thorough profile analyses on the structure changes were performed applying XPS. Some unwished phenomena like diffusion and interactions with the substrate also were investigated. To identify the optical properties of the films the methods of visual spectrophotometry and laser ellipsometry were used. The reflectance of the films in the thermal IR range was investigated by FTIR spectrophotometer.