Characteristics of rutile TiO2 films prepared by rf magnetron sputtering at a low temperature

TiO2 films were prepared by r.f. (13.56 MHz) magnetron sputtering using a mixture of Ar and O-2 gases. It was found that the crystalline structure strongly depends on the radial position of the substrate and on the total pressure of the sputtering gas. At a total pressure of 0.27 Pa, rutile TiO2 films were successfully obtained on a non-heated substrate located at a radial position of 33 mm with r.f. power of 200 W. While anatase TiO2 films were deposited at a pressure of 2.7 Pa. The deficiency of oxygen and the incorporation of Ar were observed in rutile films prepared on a Si substrate. In addition, rutile films grown on Si substrate were composed of crystal grains which are larger than 100 nm. The optical analysis showed that rutile films on a quartz substrate have a high refractive index of 2.67 at a wavelength of 370 nm.