Properties of Bi₄Ti₃O₁₂ thin films grown at low temperatures

Bismuth titanate (Bi₄Ti₃O₁₂) thin films have been deposited on a (100) silicon substrate with a buffer layer, using a rf planer magnetron sputtering technique. The buffer layer was formed by the heat treatment of an amorphous layer at 550°C, and exhibits a pyrochlore phase with a smooth surface. The amorphous layer consists of Bi, Ti and O atoms, which are the elements of the ferroelectric Bi₄Ti₃O₁₂ thin film. Ferroelectric Bi₄Ti₃O₁₂ thin films were deposited on the buffer layer at a low substrate temperature of 500°C. The Bi₄Ti₃O₁₂ thin films have a dense and small grain structure. A D-E hysteresis characteristic has been observed at room temperature. The apparent remanent polarization and the apparent coercive field of this film at the measurement frequency of 50 Hz were estimated to be 2.4 μC/cm² and 2.3 kV/cm, respectively.