Crystal Structure And Optical Properties Of TiO2 Thin Films Prepared By Reactive RF Magnetron Sputtering

Abstract

In sputtering deposition process of TiO[2], metal Ti or sintered TiO[2] target is used as deposition source. In this study, we have compared the characteristic of target materials. When TiO[2] target was used, stoichiometric TiO[2] films was deposited under the Ar atmosphere containing 1.0% of oxygen. The highest sputtering rate under this atmosphere was 3.9nm/min at 3.4W/cm[2]. But, sintered TiO[2] target is fragile and cannot endure higher density of input power than 3.4W/cm[2]. On the other hand, Ti target needs higher oxygen concentration (8%) in sputtering gas atmosphere for obtaining rutile/anatase. Even though Ti target can be input twice power density of 7.9W/cm[2], the highest deposition rate for Ti target was 1.4/nm, which was ~35% of the highest rate for TiO[2] target. Then we have study out the composite target consisting of Ti plate and TiO[2] chips. Using the composite target, stoichiometric TiO[2] films were prepared in the rate of 9.6nm/min at 6.8 W/cm[2] under the atmosphere of Ar/2.5%O[2]. Furthermore, we have found that the TiO[2] films obtained from the composite target consisted of about 100% anatase, whereas TiO[2] films obtained from other target have rutile dominant structure. The optical band gap energy of the film is determined by using the Tauc plot. The calculated band gap energies for the films deposited by Ti target and composite target were 2.95 and 3.24eV, which are equivalent to that of rutile and anatase structure, respectively.