Metalorganic Chemical Vapor Deposition of Epitaxial SrBi2Ta2O9 Thin Films and Their Crystal Structure

Abstract
Epitaxial SrBi2Ta2O9 (SBT) thin films were grown by metalorganic chemical vapor deposition using Bi(CH3)3–Sr[Ta(O·C2H5)6]2–O2 sources. The SBT 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°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 SBT phase when the deposition temperature was greater than 640°C. These epitaxial relationships appear to be related to the crystal structure and lattice mismatch between the film and substrate.