BaTi₄O₉ thin film prepared by rf magnetron sputtering for microwave applications

We attempted to produce BaTi₄O₉ dielectric thin films using conventional rf magnetron sputtering combined with subsequent rapid thermal processing (RTF). By adjusting growth and RTF temperatures, a single-phase BaTi₄O₉ film was successfully fabricated via 550°C deposition followed by 900°C annealing. The film exhibited superior physical and dielectric properties which were comparable to bulk ceramic behaviors. It showed good surface flatness and high density corresponding to 98% of the theoretical one. Its dielectric constant and dissipation factor at 6 GHz were 37 and 0.005, respectively.