Fabrication of Sr₂Nb₂O₇ thin films by sol-gel processing

Sol-gel Sr₂Nb₂O₇ thin films were deposited on Si(100) and Pt-coated Si substrates for the first time by spin-coating. The Sr₂Nb₂O₇ precursor solution was prepared from strontium metal dissolved in 2-methoxyethanol, acetylacetone, and niobium ethoxide. The formation of phase pure Sr₂Nb₂O₇ occurred via an intermediate perovskite phase of composition close to Sr_0.82NbO₃. Crack-free Sr₂Nb₂O₇ films of ∼0.4 μm thickness were deposited on these substrates using a single-coating followed by heat treatment at 850 °C for 12 h. SEM microstructure and thin film XRD results indicated the deposition of a grain-oriented film on the Pt-coated Si substrate. The room temperature dielectric constant and the loss values of the film measured at 10 kHz are 45 and 0.045, respectively.