Polycrystalline (1−x)Ta₂O₅−xTiO₂ thin films were formed on Si by metalorganic decomposition (MOD) and annealed at various temperatures. As-deposited films were in the amorphous state and were completely transformed to crystalline after annealing above 600°C. During crystallization, a thin interfacial SiO₂ layer was formed at the (1−x)Ta₂O₅−xTiO₂/Si interface. Thin films with 0.92Ta₂O₅–0.08TiO₂ composition exhibited superior insulating properties. The measured dielectric constant and dissipation factor at 1MHz were 9 and 0.015, respectively, for films annealed at 900°C. The interface trap density was 2.5×10¹¹cm⁻²eV⁻¹, and flatband voltage was −0.38V. A charge storage density of 22.8fC/μm² was obtained at an applied electric field of 3MV/cm. The leakage current density was lower than 4×10⁻⁹A/cm² up to an applied electric field of 6MV/cm.