O2 Gas Pressure Effects on Surface Morphology in Ferroelectric Bi4Ti3O12 Thin Films Fabricated by Spin-Coating Pyrolysis

Fabrication of ferroelectric Bi4Ti3O12 thin films was carried out by spin-coating pyrolysis of Bi and Ti naphthenates and successive heat treatments in O2 gas. Heat treatments in O2 gas were effective for fabrication of ferroelectric Bi4Ti3O12 thin films with c-axis orientation. It was confirmed that the film surface morphology strongly depends on the O2 gas pressure. Smooth platelike grains of the size greater than 10×10 µm2 formed extensively in thin films upon heat treatment at the O2 gas pressure of 4.0×105 Pa. The film thickness was 500 nm. The thin film was a single phase of Bi4Ti3O12 completely oriented along the c-axis with good ferroelectric properties at room temperature: coercive field of 15 kV/cm, remanent polarization of 1.9 µC/cm2, dielectric constant of 43 and loss of 0.02.