Oriented growth of SrBi2Ta2O9 ferroelectric thin films

Abstract
We report on the ferroelectric properties of c‐axis oriented ferroelectric SrBi2Ta2O9 thin films. Pt/SrBi2Ta2O 9/Pt capacitors were grown on single crystal MgO (and/or SrTiO3) substrates using pulsed laser ablation. These substrates provide the necessary template for (100) texture in platinum due to their close lattice matching. This in turn facilitates the c‐axis orientation in the ferroelectric films. The degree of orientation in the layered structure ferroelectric film was systematically varied from highly c‐axis oriented to random polycrystalline by varying the growth conditions of the bottom metal electrode. The polarization and coercive field values were found to decrease with an increasing degree of c‐axis orientation; while the randomly oriented films exhibited a remnant polarization of 5 μC/cm 2, a coercive field of 70 kV/cm, and a dielectric constant of 320, the c‐axis oriented films exhibited very low polarization (∼1 μC/cm2), coercivity (22 kV/cm), and dielectric constant (∼200) values.