Dielectric Properties and Impedance Spectroscopy of RF Sputtered Nanocrystalline (Mg0.95Zn0.05)TiO3 Films for Electronic Applications

Abstract

Oxide thin films attracted significant attention because of their favorable responses, especially dielectric and stable electrical properties. In this study, nanocrystalline (Mg0.95Zn0.05)TiO3 (MZT) films are deposited on Pt/TiO2/SiO2/Si and quartz substrates by radio-frequency (RF) reactive magnetron sputtering. The effect of deposition gas ratio, i.e., the proportion of oxygen and argon (O2/Ar) on broad band and microwave dielectric properties and impedance spectroscopy of MZT films are investigated. The dielectric properties showed a wide range of variation with the different O2/Ar ratios. The MZT film deposited in a pure oxygen environment showed the best dielectric properties, and the plasma survived which shows that the target is not fully oxidized. The impedance spectroscopy of the film deposited under a pure oxygen environment exhibited the single semi-circular arc. The Ag/ MZT/Pt thin films capacitors exhibited the best dielectric constant with low loss tangent. The microwave dielectric constant measured at different spot frequencies in the GHz range displayed inferior dielectric response as compared to their bulk counterparts. An equivalent circuit model to explain the Nyquist plots of MZT films are worked out. The observed electrical and dielectric characteristics of the thin films suggest interesting applications in dielectric mirror and integrated circuits.