Preparation of Bi4Ti3O12 films on a single-crystal sapphire substrate with electron cyclotron resonance plasma sputtering

Abstract

Bi-Ti-O oxide thin films were prepared on a sapphire single-crystal substrate by electron cyclotron resonance (ECR) plasma sputtering. The target used was a sintered Bi4Ti3O12(BIT) and the substrate was controlled in the temperature range 400–640 °C(Tsub). The film sputtered at Tsub=400 °C was a pyrochlore type oxide(Bi2Ti2O7), which changed to a Bi4Ti3O12 oxide in the polycrystalline state at 500 °C and in the single crystalline state at 640 °C. In the film sputtered at 640 °C, the (001) plane of the Bi4Ti3O12 grew parallel to the (112̄0) and (11̄02) planes of the sapphire substrate, and the (104) plane of Bi4Ti3O12 grew parallel to the (0001) plane of the sapphire substrate. The deposition rate was about 200 Å/min independent of the sputtering conditions.