Initial growth of SrBi 2Ta 2O 9 thin films on various substrates

Abstract

We have investigated the initial growth of the SrBi 2Ta 2O 9 (SBT) thin films on MgO, SrTiO 3 (STO), (LaAlO 3) 0.3(Sr 2AlTaO 6) 0.7 (LSAT), LaSrAlO 4 (LSAO) and MgAl 2O 4 (MAO) substrates by atomic force microscopy (AFM). Three types of growth modes corresponding to the degree of lattice mismatch between the thin film and the substrate have been observed. The films prepared on the substrates with a small lattice mismatch such as on STO and LSAT grow in step-flow mode, whereas the films on MgO, which has the larger lattice mismatch of 7.6%, grow three-dimensionally from the initial stage of the growth. In the case of MAO and LSAO, for which lattice mismatches are 3.3% and −1.8%, the islands with flat terraces were formed along the a and b axis of the substrates.