Effect of substitution of Ti by Zr in BaTiO3 thin films grown by MOCVD

Thin films of the solid solution BaTiO3-BaZrO3 Were studied. Such lead-free, environmental friendly materials are known, from dielectric measurements, to exhibit relaxor behaviour in bulk materials with increasing the Zr content. Ba[Ti(1-x)Zrx]O-3 thin films with various x values were prepared by liquid injection MOCVD by varying the corresponding x' value in solution (from 0.00 to 0.80). The films were studied by X-ray diffraction, Raman spectroscopy and microprobe analysis. A single perovskite phase with a linear evolution of the out-of-plane lattice parameter was identified by X-ray diffraction up to x' = 0.25. For higher Zr contents a secondary ZrO2 phase was detected. Raman spectroscopy was used to follow the subtle evolution of the crystal structure as a function of the chemical composition. The dielectric properties of single-phase layers were investigated in the range 20 600 K and 0.02-100 kHz. For some composition, the measured dielectric constant displayed a frequency-dependent behaviour. (C) 2002 Elsevier Science Ltd. All rights reserved.