Characterization of MOCVD PbTiO3thin films

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Abstract
The metal-organic chemical vapor deposition (MOCVD) technique has excellent potential for the deposition of device-quality ferroelectric thin films. The MOCVD method has been applied to the preparation of perovskite PbTiO3 thin films on fused silica and Pt-coated alumina substrates. An MOCVD system has been designed and built to deposit PbTiO3 films starting from organic precursors (tetraethyl lead and titanium isopropoxide). A wide range of conditions were investigated, and the conditions suitable for the deposition of perovskite PbTiO3 were identified. The stoichiometry of the PbTiO3 films as determined by electron microprobe analysis was variable over a wide range, and two types of microstructures, either faceted or nodular were produced. When prepared under appropriate deposition conditions, the MOCVD PbTiO3 films exhibited nominally phase-pure perovskite XRD patterns. However, the lattice parameters calculated by x-ray diffraction (a = 3.91 and c = 4.09 angstroms) indicated a slightly lesser degree of tetragonality in MOCVD PbTiO3 than would be expected for bulk material. The MOCVD PbTiO3 films also exhibited preferred crystallographic orientation, and this orientation was dependent on the deposition conditions.