Influence of deposition temperature on structural and ferroelectric properties of Bi4Ti3O12 thin films

Bismuth titanate thin films were deposited using in situ layer-by-layer reactive DC magnetron sputtering. Films were deposited on platinized silicon (Pt/Ti/SiO2/Si) substrates at the temperature of 400-500 °C. The study focused on the dependency of structural, morphological and ferroelectric properties on the parameters of material growth. Thin films, which were formed at the temperature of 450-500 °C, have dense columnar structure and flat surface. Hysteresis measurements revealed the ferroelectric nature of some of the studied films, except for the films deposited at the temperature lower than 450 °C. It was demonstrated that the volatility of bismuth oxide is affected by the temperature starting at 475 °C. The highest coercive field and remnant polarization of Ec = 130 kV/cm and of Pr = 73 μC/cm2 was obtained for film deposited at 450 °C. It appeared that the shape was clearly influenced by a certain extrinsic contribution (other than leakage) which produces an overestimation of the remnant polarization. Based on the results of the current leakage data investigation, it was established that films exhibit the space charge limited conduction.