High-resolution transmission electron microscopy study on the solid-phase crystallization of amorphous SrBi_2Ta_2O_9 thin films on Si

摘要

During the solid-phase crystallization of amorphous SrBi_2Ta_2O_9 (SBT) thin films, the grains grew preferentially to the <110> direction forming elliptical grains. The origin of the <110>-oriented grain growth is due to the highest ionic packing (001) SBT plane which includes TaO_6 octahedra, and the nearest bonding direction of TaO_6 octahedra in SBT plane is the <110> direction. High-resolution transmission electron microscopy and image computer simulation indicate that antiphase boundary enhances elliptical grain growth between the amorphous matrix and the crystalline SBT grain. The formation of a stacking fault results in an antiphase boundary making an atomic step of {001} planes at the Amorphous/crystalline interface. At that interface, a corner of the antiphase boundary acts as preferable nucleation sites By providing an atomic step of {001} planes and enhances elliptical grain growth I in the <110> direction on {001} Planes.