Growth and polarization feature studies on rapid thermally processed preferentially c-axis-oriented Bi4Ti3O12 thin films on Si by sol–gel

Crack free Bi4Ti3O12 ferroelectric films were fabricated by sol–gel method with rapid thermal annealing (RTA) techniques on p-Si and Pt/Ti/SiO2/p-Si substrates. The effects of annealing temperature and time on microstructure, growth behavior and polarization feature of Bi4Ti3O12 films were investigated. The patterns of X-ray diffraction (XRD) exhibited that Bi4Ti3O12 film on bare Si substrates is c-axis-orientation with the increase of annealing temperature and without any pyrochlore phase or other second phase, but Bi4Ti3O12 film on Pt/Ti/SiO2/p-Si substrate is not c-axis-orientation and there is pyrochlore phase in it. Annealing time of 5 min is enough to attain perovskite phase at 550 °C and highly c-axis-oriented Bi4Ti3O12 films can be obtained at 850 °C, but the compatible annealing temperature for best ferroelectric properties with a remanent polarization of 8.44 μC/cm2 is 700 °C. The cross-sectional SEM photographs and the capacitance-voltage (C–V) curve of Ag/Bi4Ti3O12/p-Si demonstrate that the good interface characteristics of Bi4Ti3O12/p-Si can be obtained by sol–gel method with rapid thermal annealing techniques, which suggests that the Ag/Bi4Ti3O12/p-Si configuration is promising for memory applications.