Characterization of zinc-modified lithium tantalate thin films fabricated by chemical solution deposition method

Zinc-substituted lithium tantalate thin films were fabricated for improving the electrical resistivity by compensating the valence of lattice defects in LiTaO3 crystal. The films with the chemical composition of (Li1.00-xZnx)TaO3 were fabricated on (111)Pt/TiO2/SiO2/(100)Si substrate by a chemical solution deposition technique using metal-organic precursors. Dense films consisting of a ilumenite-type crystalline phase were deposited by spin coating on the substrates, followed by heat-treatment at 650°C for 5 min in air. The leakage current density of the LiTaO3 film was reduced from approximately 10−4 to 10−6 A/cm2 by substituting Zn2+ ions for Li+ ions in the LiTaO3 films. Polarization–electric field hysteresis loop was improved significantly by partial substitution of Zn2+ for Li+ ions, which is based on the enhancement of electrical resistivity.