Preparation And Electrical Properties Of TiO₂/Metal/ITO Glass (SI) Thin Films

TiO2 films have been widely applied to paint, coating, chemical fiber, plastic, cosmetics and ceramics because of its high dielectric constant, high refraction index, high chemical stability and semiconductor characteristics. Moreover, TiO2 films have important application prospect in photocatalysis, building materials, solar cell, and many other aspects. So the investigation on TiO2 films has certain practical value.There are three kinds of crystalline phases including brookite, anatase and rutile for TiO2. Brookite is unstability and little in nature. Anatase and rutile structure are stability and have wider applications. These two structures were mainly studied in this paper.TiO2 films have been prepared by a variety of deposition techniques as its attractive properties, such as the sol-gel process, chemical vapor assisted process, ion beam assisted process, atomic layer deposition, various reactive sputtering techniques, pulsed laser deposition, and filtered arc deposition. TiO2 films with good structure can prepared by sol-gel process, but this method is difficuilt in technology and out of hand. In most of these techniques, additional heating during deposition or post heating is required to synthesis crystalline phases of TiO2 films. The magnetron sputtering equipment is easy to operate and control. Moreover, repeatability is good and many kinds of films can be deposited by means of magnetron sputtering method. The two phases of TiO2 films can be deposited at normal temperature by magnetron sputtering, and the quality of the film was well. For the application of different phases is different, the study on the phase change have theoretical and applied value.In this peper, the TiO2 films with mixed and singled rutile and anatase phases were successfully deposited on Si, ITO glass and metal/ITO glass. We obtained the optimum condition of rutile and anatase TiO2 films growth by changing deposition oxygen content, sputtering pressure, sputtering power, sputtering time, substrate temperature. Higher oxygen content and higher sputtering pressure were good for rutile deposition. Heated substrate, lower oxygen content and lower sputtering pressure were good for anatase deposition. We also found that the substrate materials influenced the films'structure. Silicon substrates and ITO glass substrates were easy for depositing rutile phase and anatase phase, respectively. At the same time, we deposited TiO2 films on metal/ITO glass and studied the variation tendency of rutile and anatase phase. The structure of the film deposited on metal/ITO glass changed from singled anatase phase to mixed anatase and rutile phases with increasing time. TiO2 films were easier deposited on metal/ITO glass than ITO glass. At last, the conductivity of TiO2 films on the thickness of the film and the substrate material were educed. The TiO2/Ti/ITO glass films varied in the range from conductor, semiconductor to nonconductor, TiO2/Si films varied in the range from semiconductor to nonconductor. This was attributed to the different work function for TiO2 and Ti/ITO glass, Si substrates.