Substrate potential effects on low-temperature preparation of SrTiO3 thin films by rf magnetron sputtering

SrTiO3 films have been prepared by RF magnetron sputtering at a low substrate temperature of 200degC. The dielectric properties of the films deposited wherein substrate potentials were floated were fairly dependent on the film thickness, which was related to a change of the substrate potential at the initial stage of deposition. In order to control the substrate potential, positive DC bias voltages were applied on substrates, so that leakage current densities of the films were markedly reduced while their dielectric constants and structural properties remained almost the same. A 300-nm-thick film deposited with DC bias voltages >+5 V exhibited. good dielectric properties with a leakage current density of 1x10-7 A/cm2 and dielectric constant of 90. (author)