PbTiO(3) films from metalloorganic precursors

Preparation and characterization of chemically derived (Pb,La)TiO (3) thin films

Ferroelectric lead lanthanum titanate (PLT) thin films with composition varying from pure PbTiO(3) to PLT 25/100 (0 to 25 mol.% La) were prepared by spin-casting 0.25M solutions containing metallo-organic precursors of Pb, La, and Ti. The dielectric and ferroelectric properties of the thin (410-nm) films were characterized. The dielectric constants of the films varied from ~80 to ~690 for La contents varying from 0 to 25 mol%, respectively. Dissipation factors varied from ~0.03 to ~0.09 over the same compositional range. The temperature dependence of the dielectric properties was also studied to determine the effects of La content on the Curie point (T(c)). As expected, T(c ) was found to decrease with increasing La concentration. Coercive field and remanent polarization also decreased with increased La concentration.

Metalloorganic solution deposition of ferroelectric PZT films

The metallo-organic solution deposition (MOSD or sol-gel) technique can be used for preparing lead zirconate titanate (PZT) ceramics with a wide range of compositions and crystal structures for electrooptical applications. Film morphology is affected by the stoichiometry of the film, hydrolysis and polymerization of the sol-gel solution, and thermal treatment of the deposited material. The lattice parameter decreases with the amount of titanium in the PZT, in agreement with ceramic data. A slight initial excess of lead in the coating solution is found to improve film morphology. Unlike traditional powder ceramic processing techniques, MOSD permits the growth of small uniform grains that are conducive to achieving consistent electronic and optical properties. Results show that the properties of films prepared by the MOSD process can be tailored to meet the needs of device applications.