DIELECTRIC-PROPERTIES OF TIO2-FILMS REACTIVELY SPUTTERED FROM TI IN AN RF MAGNETRON

The dependence of the dielectric constant epsilon(r), chemical composi tion and crystalline structure of thin titanium oxide films, deposited onto Si substrates, on reactive sputtering conditions has been studie d using an RF magnetron operated under different conditions of substra te temperature and O-2 + Ar gas composition. The effect of post-deposi tion annealing in O-2 was also examined. X-ray photoelectron spectrosc opy (XPS) analysis showed the layers were stoichiometric TiO2 and a Si O2 layer existed between Si substrate and TiO2 with a thickness of abo ut 23 Angstrom. Reflection High Energy Electron Diffraction (RHEED) re vealed that films were mostly amorphous but some were partially crysta llized structures of anatase. Dielectric constants were in the range o f 16-52. epsilon(r) was found to increase slightly with increasing O-2 contents in the discharge gas. Increasing the deposition substrate te mperature raised epsilon(r). Post-deposition annealing increased epsil on(r) of layers deposited with small O-2 partial pressures and decreas ed it for layers deposited with large O-2 contents. It also converted amorphous and anatase films to anatase-rutile mixture films with rutil e prevailing in layers deposited with 3% O-2. The thickness of the SiO 2 intermediate layer increased by about 20%. Copyright (C) 1996 Elsevi er Science Ltd