Determination of oxygen diffusion kinetics during thin film ruthenium oxidation

摘要

In situ X-ray reflectivity was used to reveal oxygen diffusion kinetics for thermal oxidation of poly-crystalline ruthenium thin films and accurate determination of activation energies for this process. Diffusion rates in nanometer thin RuO_2 films were found to show Arrhenius behaviour. However, a gradual decrease in diffusion rates was observed with oxide growth, with the activation energy increasing from about 2.1 to 2.4 eV. Further exploration of the Arrhenius pre-exponential factor for diffusion process revealed that oxidation of polycrystalline ruthenium joins the class of materials that obey the Meyer-Neldel rule.