Processing effects on the composition and dielectric properties of hydrothermally derived BaxSr(1−x)TiO3 thin films

Abstract

Polycrystalline BaxSr(1−x)TiO3 (BST) thin films were processed on Pt-coated glass substrates at temperatures below 100 °C by reacting TiO2 films in alkaline solutions containing Ba2+ and/or Sr2+. The TiO2 was deposited by spin-casting a titanium metalorganic precursor onto Pt-coated glass substrates, followed by pyrolysis in air at 400 °C. Film stoichiometry deviated from the initial solution composition, with a preferred incorporation of Sr2+ into the perovskite lattice. The BST thin films had dielectric constants ranging from 100 to 185 and dielectric loss values below 0.25. Capacitance–voltage and current–voltage relationships were examined to determine the effect of phase stoichiometry and processing route on dielectric properties.