Preparation, structure and dielectric properties of substrate-free BaTiO₃ thin films by sol–gel method

An innovative method of preparing substrate-free BaTiO₃ thin films was proposed and used to demonstrate that the BaTiO₃ thin films can be peeled off from the substrates. Structure, morphology and dielectric properties of these thin films were studied. The BaTiO₃ thin films consist of a perovskite phase having a cubic symmetry and showed a dense and crack-free structure after being annealed at 800 °C. SEM and AFM results showed that the nano-structured BaTiO₃ thin films were dense and crack-free with an average grain size of 60 ± 5 nm and the surface root-mean square (RMS) roughness was 6.83 nm. The dielectric measurements indicated that the substrate-free thin films annealed at a temperature of 800 °C possessed a dielectric constant of ε_r = 245 and loss tangent of tan δ = 0.057. The new method we put forward could effectively reduce the volume of a film capacitor without any decline in its dielectric properties, thus showing promise as a new approach for preparing embedded thin-film capacitors.