Structure and ferroelectric properties of alkoxy-derived Ca2Bi4Ti5O18 thin films on Pt(111)/TiOx/SiO2/Si(100)

Ca2Bi4Ti5O18 (CBTi245) thin films were prepared by spin-coating with a precursor solution of metal alkoxides. The onset of crystallization of the thin films to a pyrochlore phase was realized below 550°C via rapid thermal annealing in oxygen. A perovskite phase was developed by further annealing at temperatures of 650°C or higher. The CBTi245 thin films crystallized on Pt(111)/TiOx/SiO2/Si(100) substrates showed random orientation, a columnar structure, and P-E hysteresis loops. The remanent polarization and coercive electric field of the 650°C-annealed CBTi245 thin film were 4.7 μC/cm2 and 111 kV/cm. respectively, at 12 V. The dielectric constant and loss factor were 330 and 0.028, respectively, at 100 kHz.