Metalorganic chemical vapor deposition of epitaxial SrBi2Ta2O9 thin films and their crystal structure

Epitaxial SrBi2Ta2O9 (SBT) thin films were grown by metalorganic chemical vapor deposition using Bi(CH3)(3)-Sr[Ta(O . C2H5)(6)](2)-O-2 sources. The SET phase with the c-axis oriented normal to the substrate and the fluorite phase with its a-axis oriented normal to the substrate could be deposited onto (100)SrTiO3 and (100)yttria-stabilized zirconia (YSZ) substrates at 640 and 750 degrees C, respectively. On the other hand, the films deposited onto (100)LaAlO3 substrates consisted of the a-axis oriented fluorite phase together with the c-axis oriented SET phase when the deposition temperature was greater than 640 degrees C. These epitaxial relationships appear to be related to the crystal structure and lattice mismatch between the film and substrate.