Zirconium tin titanium oxide doped 1 wt % ZnO thin films on n-type Si substrate were deposited by rf magnetron sputtering at a fixed rf power of 350 W with various argon-oxygen (Ar/O2) mixture and different substrate temperatures. Electrical properties and microstructures of ZnO-doped (Zr0.8Sn0.2)TiO4 thin films prepared by rf magnetron sputtering on n-type Si(100) substrates at different Ar/O2 ratios and substrate temperatures have been investigated. The surface structural and morphological characteristics analyzed by x-ray diffraction, scanning electron microscopy, and atomic force microscope were sensitive to the deposition conditions, such as Ar/O2 ratio (100/0–80/20) and substrate temperature (350 °C–450 °C). The selected-area diffraction pattern showed that the deposited films exhibited a polycrystalline microstructure. All films exhibited ZST (111) orientation perpendicular to the substrate surface and the grain size as well as the deposition rate of the films increased with the increase of both the Ar partial pressure and the substrate temperature. At a Ar/O2 ratio of 100/0, rf power level of 350 W and substrate temperature of 450 °C, the Zr0.8Sn0.2TiO4 films with 6.44 μm thickness possess a dielectric constant of 42 (at 10 MHz), a dissipation factor of 0.065 (at 10 MHz), and a leakage current density of 2×10−7 A/cm2 at an electrical field of 1 kV/cm. © 2004 American Institute of Physics.