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

Abstract

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 er = 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.