Characterization of sputtered iridium dioxide thin films

Iridium dioxide (IrO₂) thin films, deposited on Si substrates by reactive rf sputtering method under various conditions, were characterized by atomic force microscopy (AFM), x-ray diffraction (XRD), electrical-conductivity, spectrophotometry, ellipsometry and Raman scattering measurements. The average grain sizes of the films were estimated by AFM. A grain boundary scattering model was used to fit the relation between the average grain size and electrical resistivity. The optical and dielectric constants were determined by the ellipsometry measurements. The results of the electrical and optical studies show a metallic character of the films deposited at higher temperatures. The results of XRD and Raman scattering indicate that the IrO₂ films deposited at temperatures higher than 300 °C show the presence of (200) texture.