Effect of the substrate heating due to the sputtering process on the crystallinity of TiO 2 thin films H. Toku, R. S. Pessoa, T. B. Liberato, M. Massi, H. S. Maciel, A. S. da Silva Sobrinho Plasmas and Processes Laboratory – Department of Physics, Technological Institute of Aeronautics, 12228-900, S.J. Campos, Brazil This article reports on the effect of the increase of substrate temperature due to the plasma discharge on the crystalline structure of the TiO 2 thin films deposited on silicon by the magnetron sputtering technique. The influence on the film crystallinity was evaluated as a function of process parameters, such as, substrate-to-target distance and reactive gas concentration. The substrate holder was equipped with two thermocouples in order to measure simultaneously the substrate temperature T s and the substrate surface temperature T surf during the deposition. The films were analyzed by X-ray diffractometry (XRD) and profilometry. Results show that the critical temperature to obtain crystalline films depends upon the gas composition and it varies from 170ºC - 210ºC for oxygen concentration in the gas mixture varying from 20 to 100%. Introduction The excellent mechanical and electrical properties of titanium oxide (TiO 2 ) are very attractive to the microelectronic industry which makes it subject of study of many researches groups worldwide. The TiO 2 possesses three crystalline structures in bulk form: anatase (tetragonal), rutile (tetragonal) and brookite (orthorhombic). In contrast to amorphous TiO 2 , crystalline TiO 2 with anatase or rutile phase has attracted more interest due to its outstanding optical, electrical and chemical properties which make it suitable for a variety of thin film applications. For example, anatase TiO 2 films has better photocatalytic activity allowing its use in many applications as photochemical solar cell and gas sensor, e.g. the detection of NO 2 (2). On the other hand, rutile TiO 2 film has high dielectric constant, which makes it very attractive for use in the fabrication of diodes and capacitors in microelectronic devices. Due to its high refractive index (~2.5) and optical transparency in the visible range, the rutile phase is also applied as dielectric interference filters, antireflective coating, and optical wave guides, to state few (3). Since the performance of electronic devices depends substantially on the crystalline quality of the thin films employed, numerous efforts have been done to improve the quality of these devices by dealing with several kinds of film growth techniques. The methods used to fabricate crystalline thin films are, chemical vapor deposition, electron beam evaporation, pulsed laser deposition, molecular beam epitaxy and reactive magnetron sputtering. Among these methods, the sputtering is the most versatile technique to prepare good quality crystalline thin films (4). The substrate temperature is an important factor to determine the crystallinity of film deposited by reactive magnetron sputtering deposition. It is well known that high temperature processes favor the formation of crystalline films. Nonetheless, elevated temperature deposition can induces degradation of layered structures as interfacial ECS Transactions, 9 (1) 189-197 (2007) 10.1149/1.2766888 © The Electrochemical Society 189 Downloaded 02 Jan 2011 to 187.2.100.88. Redistribution subject to ECS license or copyright; see http://www.ecsdl.org/terms_use.jsp