Microstructure and electrical properties of chemical solution deposition (Pb,La)(Zr,Ti)O-3 thin films on Pt electrodes

(Pb,La)(Zr,Ti)O-3 (PLZT) films with thicknesses of 150 and 225 nm were prep ared by the chemical solution deposition method on sputtered Pt/IrO2 coated on SiO2/Si wafers. The annealed films revealed two different microstructur es: 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 th e grain boundary triple points. These triple points also contained a nanocr ystalline nonstoichiometric secondary phase, which contributed to high leak age. A model was developed showing differences in crystallization on the ba sis of gain growth and number of nuclei on the Pt surface. These results in dicate the importance of controlling the film microstructure and its relati onship to the film electrical properties.