Influence of Ar+ ion bombardment on the chemical states of SrBi2Ta2O9 thinfilms fabricated by metalorganic decomposition

The SrBi2Ta2O9 (SBT) films studied for this report were prepared by metalor ganic decomposition. The SBT thin him, which belongs to a Bi-layered perovs kite structure where double Ta-O octahedron layers are sandwiched between ( Bi2O2)(2+) layers, was analyzed to characterize chemical states using x-ray photoelectron spectroscopy during depth-profiling analysis. When sputter e tching was performed on the SBT film by Ar+ ion bombardment, the chemical s tates of constituents in the SET film were changed as a function of the app lied Ar+ ion-beam energy. Among the constituents of the SET film, the Sr 3d peak was changed slightly by the change of Ar+ ion-beam energies. On the o ther hand, the changes of Ta 4f and Bi 4f peaks obviously depended on the a pplied Ari ion-beam energies. In particular, the Bi 4f peak changed dramati cally from Bi-O states to Bi metallic states by the lower Ar+ ion-beam ener gies than in the cases of Sr and Ta. This change of chemical states of the SET film resulted from the preferential sputtering of oxygen atoms. Followi ng our present study, preferential sputtering of oxygen atoms was found to depend on the thermal stability and mass difference between oxygen and each constituent within the SET films. (C) 2001 American Vacuum Society.