Synthesis and characteristics of Bi3.25La0.75Ti3O12 ferroelectric thin films by sol-gel technology

Bi3.25La0.75Ti3O12 thin films were prepared on p-Si substrates by Sol-Gel technology. The effect of annealing temperature on microstructure, morphology, dielectric and ferroelectric properties of Bi3.25La0.75Ti3O12 films was investigated. Bi3.25La0.75Ti3O12 films annealed at 500℃ were not very uniform, they consisted of small grains and coarse grains with poor dielectric and ferroelectric properties. When the annealing temperature was over 550℃, Bi3.25La0.75Ti3O12 films were uniform and crack free as well as exhibiting no preferred orientation with good dielectric and ferroelectric properties. The leakage current density of Bi3.25La0.75Ti3O12 thin films is 2×10-8A/cm2 at 4V. A noticeable improvement of ferroelectric properties have been obtained when the annealing temperature was increased. Bi3.25La0.75Ti3O12 films annealed at 600℃ showed excellent dielectric and ferroelectric properties with a dielectric constant of 288, a dielectric loss of 1.57%, a remanent polarization of 17.5μC/cm2 and a coercive field of 102kV/cm.