The Optical and Electrical Properties of Ta₂O₅/TiO₂Thin Films Deposited by dc Reactive Magnetron Sputtering

Ta₂O₅/TiO₂ thin films were grown on glass and Si substrates by dc reactive magnetron sputtering. The composition of Ta₂O₅/TiO₂ films was adjustal by suitable selection of the area ration of the superposed tantalum and titantitum plates. The transmission spectra measurement showed that all as-depsoited Ta₂O₅/TiO₂ films have high transmission above 60%. The refractive index of the compostie film was found to vary almost linearly with composite, say,the refractive index varied from 2.08 to 2.23 as a function of TiO₂ concentration from 0 to 17%. The capactitance - voltage （C-V） measurement of Ta₂O₅/TiO₂ films in the Metal-Oxide-Semiconductor （MOS） capacitor could be performed and the accumulation, depletion and inversion phenomena were clearly indicated. The electrical and dielectric properties of Ta₂O₅/TiO₂ films were strongly dependent on the TiO₂ concentration of composite films and post-deposition annealing treatment. These results showed that high temperature annealing improved significantly the dielectrical characteristics of Ta₂O₅/TiO₂ films, While TiO₂ has no effect on improving the dielectric and insulating properties of Ta₂O₅ film.