Anatase and rutile TiO₂ films deposited by arc-free deep oscillation magnetron sputtering

Phase control of TiO₂ films at low deposition temperatures is important for many applications. In this study, nanocrystalline TiO₂ films were synthesized on glass and steel substrates in a balanced magnetron sputtering system using the new deep oscillation magnetron sputtering (DOMS) and pulsed dc magnetron sputtering (PDCMS) techniques. A virtually arc-free high-power pulsed magnetron sputtering process for TiO₂ reactive sputtering was observed for DOMS. No external substrate bias and heating were used for the depositions. For the DOMS TiO₂ depositions, different peak target currents (powers) were used. The crystal phase and microstructure of the TiO₂ films were characterized and compared. It was found that the TiO₂ films deposited by PDCMS exhibited a complete anatase phase. The TiO₂ films deposited by DOMS at a low target peak current (e.g. 50 A) also contained mainly the anatase phase. Nevertheless, an increase in the peak target current for the DOMS deposition promoted the formation of the rutile phase, increased the density and decreased the grain size of the TiO ₂ films. A complete rutile phase was obtained for the TiO₂ film deposited by DOMS at a high target peak current (200 A). The mechanical and optical properties of the anatase and rutile TiO₂ films were also studied and compared.