Phase formations and ferroelectric properties of PLT thin films by MOCVD

Abstract

La-modified lead titanate, Pb1-xLaxTiO3(PLT), thin films were prepared on Si[100] and Pt/SiO2/Si substrates by the low-pressure metalorganic chemical vapor deposition (LP MOCVD) method with the hot wall type. The PLT films were deposited at 500 degrees C with the low-pressure of 0.1 Torr, and then annealed at 650 degrees C with an oxygen ambient for 10 minutes. Irrespective of substrate properties and La molar fractions, the films revealed the [100] preferred-orientation. With increasing the La mole %(up to 34%) in the films, the surface morphology improved, and the ferroelectricity and the leakage current density decreased. On the other hand, up to the La 22 mole%, the relative dielectric constant increased from 900 to 1200.