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 TiO2 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.