Epitaxy and interfacial phase in thin films of lead scandium tantalate deposited by reactive sputtering on a platinum interlayer
1995; Taylor & Francis; Volume: 9; Issue: 4 Linguagem: Inglês
10.1080/10584589508012568
ISSN1607-8489
AutoresC. D. Meekison, K. Z. Baba‐Kishi, R. Watton, M. A. Todd,
Tópico(s)Acoustic Wave Resonator Technologies
ResumoAbstract Lead scandium tantalate (PST) films with a lead-rich composition were deposited at 500°C by RF sputtering on sapphire substrates coated with Pt and were investigated by cross-sectional transmission electron microscopy. The films consisted almost entirely of the perovskite phase. The grains of perovskite PST had a crystallographic orientation almost parallel to that of the underlying Pt. Some elongated voids were observed. The presence of an interfacial phase, with interplanar spacings consistent with a pyrochlore phase, was demonstrated by electron diffraction and dark-field imaging. The crystallographic orientation of this phase is also nearly parallel to that of the Pt. Energy-dispersive X-ray microanalysis showed that the interfacial phase is lead-deficient. The interfacial phase is irregular in thickness. A reduction in the Pb content of the film leads to a thicker interfacial layer. The implications for the mechanism of growth of PST on Pt and for improvement of the film quality are discussed.
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