Growth of uniformly a-axis-oriented ferroelectric lanthanum-substituted bismuth titanate films on silicon substrates

Uniformly a-axis-oriented, epitaxially twinned La-substituted Bi4Ti3O12 (BLT) thin films having the major spontaneous polarization entirely along the film normal were grown by pulsed laser deposition on yttria-stabilized zirconia-buffered Si(100) substrates covered with very thin SrRuO3 bottom electrodes. Using SrRuO3 bottom electrodes of a specific low thickness in combination with a relatively high growth rate and a high oxygen pressure, the volume fraction of the BLT (100) orientation, which is competing with the BLT (118) orientation, was increased up to 99%. In this way the growth of fully a-axis-oriented BLT films was achieved, attaining a remanent polarization of 32 muC/cm(2). Initial fatigue experiments indicated hardly any fatigue after 10(9) switching cycles. (C) 2003 American Institute of Physics.