Conductivity of micro-porous magnetron-sputtered thin TiO2 films

The dependence of the conductivity of thin TiO2 layers on the relative ambient humidity and on the thickness of the films is presented. The TiO2 thin films were deposited by reactive magnetron sputtering of a Ti targets in an Ar + O-2 mixture in a conventional sputtering reactor. The sputtering was carried out at room temperature of the substrate and at a total pressure of 1 Pa. The thickness of the films varied between 40 and 200 nm. The conductivity of the films was measured depending on the relative ambient humidity. It is found that the conductivity of the films depends on the relative ambient humidity following the non-linear adsorption isotherm typical of microporous layers. The microporosity of the films is also confirmed by the atomic force microscopy measurements. (C) 2000 Elsevier Science Ltd. All rights reserved.