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The dependence of the dielectric constant ϵ rr , chemical composition and crystalline structure of thin titanium oxide films, deposited onto Si substrates, on reactive sputtering conditions has been studied using an RF magnetron operated under different conditions of substrate temperature and O 2 + Ar gas composition. The effect of post-deposition annealing in O 2 was also examined. X-ray photoelectron spectroscopy (XPS) analysis showed the layers were stoichiometric TiO 2 and a SiO 2 layer existed between Si substrate and TiO 2 with a thickness of about 23 A. Reflection High Energy Electron Diffraction (RHEED) revealed that films were mostly amorphous but some were partially crystallized structures of anatase. Dielectric constants were in the range of 16–52. ϵ r was found to increase slightly with increasing O 2 contents in the discharge gas. Increasing the deposition substrate temperature raised ϵ r . Post-deposition annealing increased ϵ r of layers deposited with small O 2 partial pressures and decreased it for layers deposited with large O 2 contents. It also converted amorphous and anatase films to anatase-rutile mixture films with rutile prevailing in layers deposited with 3% O 2 . The thickness of the SiO 2 intermediate layer increased by about 20%. |
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