Microstructure and electrical properties of chemical solution deposition (Pb,La)(Zr,Ti)O3 thin films on Pt electrodes

Abstract

(Pb,La)(Zr,Ti)O3 (PLZT) films with thicknesses of 150 and 225 nm were prepared by the chemical solution deposition method on sputtered Pt/IrO2 coated on SiO2/Si wafers. The annealed films revealed two different microstructures: fined-grained and large-grained. The thinner film had the largest grain size and highest leakage current, whereas the thicker film had small grains and lower leakage. Atomic force microscope images showed that the thinner film had half-domed-shaped grains, which were about one-third thinner at the grain boundary triple points. These triple points also contained a nanocrystalline nonstoichiometric secondary phase, which contributed to high leakage. A model was developed showing differences in crystallization on the basis of grain growth and number of nuclei on the Pt surface. These results indicate the importance of controlling the film microstructure and its relationship to the film electrical properties.