Sol-gel derived LiTaO3 thin films: properties and applications

LiTaO3 thin films were deposited on platinized silicon and silicon wafers by spin coating. Double alkoxides, dissolved in parent alcohols were used as the sol precursors. Five different organic ligands, R=CH3, C2H5, n-C3H7, i-C3H7, and n-C4H9 were selected to study their effect on preferred orientation in the crystallized phases of the sintered films, which were analyzed by the X-ray diffraction techniques. It was found that the different ligand types gave rise to changes in direction as well as degree of the preferred orientation. The influence of the ligands also varied with the film thickness. As the thickness of the films increased to > 200 nm. only the double ethoxide derived films on platinized Si can maintain good degree of preferred orientation at the [110] direction. Possible causes for these effects will be discussed As an example for its applications, a thin film device utilizing the pyroelectric properties of LiTaO3 will be briefly described.