Thermodynamic Analysis of Stoichiometric Composition Changes in the TixOy Films at RF Magnetron Sputtering and Modeling of Their Conductivity

Herein, the results of experiments on the synthesis of nonstoichiometric titanium oxide films by magnetron sputtering at various partial oxygen pressures and discharge powers are presented. The thermodynamic analysis of the synthesis results is performed by minimizing the Gibbs free energy of the equilibrium thermodynamic system, which takes place in the chamber. The dependences of the concentration of the main components in the deposition chamber on the partial pressure of oxygen and the discharge power, including the concentration of synthesized titanium monoxide and dioxide, are obtained. The analysis of these dependences allows determining the conditions for the critical values of the partial pressures of oxygen at which the oxides are synthesized. The exponential dependence of the conductivity on oxygen pressure is found experimentally and explained on the basis of hopping conductivity over the states of defects on the surface of nanocrystals that form the synthesized films.