SrTiO3 thin film preparation by ion beam sputtering and its dielectric properties

SrTiO3 thin films have been prepared on Pd-coated sapphire substrates by ion beam sputtering of a SrTiO3 target, and their dielectric properties have been studied. Oxygen flow introduction was necessary to obtain good insulating films. Dielectric constant εr values were 190 and 240 for 430degC and 540degC substrate temperatures, respectively. These εr values were not dependent on film thickness in the range from 200 nm down to 50 nm. A 53 nm-thick film indicated leakage current density of less than 10-8 A/cm2 at up to 2 V, along with a 230 εr value. (author)