Structural and dielectric properties of the BaTi₅O₁₁ thin film grown on the poly-si substrate using RF magnetron sputtering

The BaTi₅O₁₁ thin films were grown on the poly-Si/SiO₂/Si substrate using rf magnetron sputtering and their structural and dielectric properties were investigated. The BaO-TiO₂ thin film deposited on the poly-Si substrate had an amorphous phase even though the growth temperature was high at 550°C. The crystalline BaTi ₅O₁₁ thin films were formed when the amorphous film was annealed above 800°C. The BaTi₅O₁₁ phase was decomposed into Ba₄Ti₁₃O₃₀, Ba ₂Ti₉O₂₀ and TiO₂ phases as the films were annealed above 1100°C. The homogeneous BaTi₅O₁₁ thin film was formed when the film was grown at 550°C and rapid thermal annealed at 900°C for 3 min. The interface between the BaTi ₅O₁₁ film and poly-Si substrate was sharp, and the inter-diffusions of the Si, Ba and Ti ions between the layers were negligible. The dielectric constant of the BaTi₅O₁₁ film was about 35, which is close to that of the bulk BaT₅O₁₁ ceramics. The dissipation factor of all the films was smaller than 4.0%.