Plasma-assisted pulsed laser deposition of SrBi2Ta2O9 thin films of improved ferroelectric and crystalline properties

Significant effect of the introduction of O2-plasma discharge during pulsed laser ablative deposition of SrBi2Ta2O9 (SBT) films on improving the crystallite orientation and ferroelectric properties has been described. O2-plasma assists in the formation of highly crystalline films at a low 700 °C temperature over (111) oriented Pt films coated Si(100) single crystal substrates at a nominal pressure of 200 mTorr. Plasma excitation potential, applied at an auxiliary ring electrode placed near the substrate, has a profound effect on surface morphology, crystallite orientation, and remnant polarization, Pr values. At −350 V, SBT growth at 700 °C with predominant (a-b) orientation showing high Pr∼6.5 μC/cm2 in the as-deposited state has been obtained. In comparison, SBT films deposited identically but without the plasma show a low Pr of ∼1.7 μC/cm2. Ionized cationic species along with ionic and atomic oxygen present in the plasma improve thermodynamic stability of the film growth through enhanced chemical react...