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

: Pantou, R.; Dubourdieu, C.; Weiss, F.; Kreisel, J.; Köbernik, G.; Haessler, W.


Materials Science in Semiconductor Processing 5 (2002), Nr.2-3, S.237-241
ISSN: 1369-8001
Fraunhofer IPMS ()

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]O3 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.