Novel Low Melting Point Barium and Strontium Precursors for the MOCVD Growth of Barium-Strontium-Titanate Films



Novel barium and strontium precursors, belonging to the family of volatile complexes of the alkaline earth element (AEE) fluorinated β-diketonates with polyglymes, [M(dfhd)2(tetraglyme)] [Hdfnd = 1,1,1,2,2,6,6,7,7,7-dekafluoro-heptane-3,5-dione, M = Ba (I), Sr (II)], are synthesized and tested with an aim to use them for metal-organic (MO)CVD of BaxSr1-xTiO3 (BST) thin films. The thermal behavior and composition of vapor phases for compounds I and II are studied by thermal analysis and mass spectrometry (MS). Considerable reduction of the melting point (down to 80–90 °C) for both compounds I and II, as compared to known volatile complexes, is achieved. By means of the developed precursors, epitaxial BST films (x = 0.5) are grown on SrTiO3 substrates by using the modified MOCVD facility. The quality of the grown films is examined by high-resolution (HR) X-ray diffraction (XRD) and high-resolution (HR) scanning electron microscopy (SEM).