Dielectric properties of ambient temperature grown nanocrystalline ZrTiO4 thin films using DC magnetron sputtering

Nanocrystalline zirconium titanate (ZrTiO4) thin films have been deposited at ambient temperature by DC reactive magnetron sputtering from individual titanium and zirconium metal targets on to platinized silicon and glass substrates. The present study demonstrates the possibility of growing zirconium titanium oxide films in 100% pure DC oxygen plasma. The processing conditions have been optimized to get the required stoichiometry of the films. The films got crystallized at temperatures below 100 °C. Interestingly, the as-deposited films crystallized in orthorhombic phase. The crystallite size in the films varies between 13.2 and 28.6 nm as calculated from the X-ray diffraction patterns and is dependent on oxygen mixing percentage (OMP) in the sputtering gas. The refractive index is strongly dependent on the packing density of the films. The dielectric constant of these films did not show much dependence on frequency whereas the loss is higher at lower frequency region. The dielectric constant and loss of the films measured at frequencies in the range of 100 Hz–15 MHz ranged between 37–46.5 and 0.007–0.03, respectively. The magnitude of leakage current density is 9.03 × 10−7 A/cm2 at 10 MV/m for the films deposited at 40% OMP. It is found that all these properties of ZrTiO4 films are strongly dependent on processing parameters.