Characteristics of ferroelectric Sr0.7Bi2.1Ta2.0O9 thin films grown by liquid delivery metal organic chemical vapor deposition process

Ferroelectric Sr0.7Bi2.1Ta2.0O9 thin films with a thickness of 200 nm were deposited on Pt(111)/Ti/SiO2/Si(100) substrate by means of the liquid delivery metal organic chemical vapor deposition process. The optimum substrate temperature and reactor pressure were 570 °C and 0.65 kPa, respectively. After depositing the thin films under optimum conditions, they were furnace-annealed at various temperatures for 1 h in oxygen ambient. Then a Pt top electrode was deposited by sputtering and the thin films were post-annealed in oxygen ambient, in order to improve their electrical properties. The surface morphology of the strontium bismuth tantalite (SBT) thin films deposited under optimum conditions showed the presence of pseudo-spherical particles and rod-shaped grains. The grains of the SBT thin films exhibited increasing growth of a layered perovskite phase with increasing annealing temperature. The remanent polarization values (2Pr) of the SBT thin film annealed at 780 °C were 7.247 and 8.485 μC/cm2 at applied voltage of 3 V and 5 V, respectively.