Substrate effect on the PLD growth of ferroelectric materials thin films

Abstract

Ferroelectric materials, namely lead zirconium titanate (PZT) and strontium bismuth niobate (SBN) have been grown on various substrates by pulsed laser deposition (PLD). In the example of PZT, the ferroelectrics nearly perovskite material often coexists with a lead deficient pyrochlore-type phase. The former is promoted by perovskite substrates like strontium titanate, lanthanum aluminate or YBa₂Cu₃O₇ sublayer and rocksalt LiF. In contrast, a CeO₂ sublayer results in the growth of pure, epitaxial pyrochlore. MgO and sapphire represent intermediate behaviors. The case of SBN is even more complex because four quaternary phases have been detected in the phase diagram. Again, perovskite substrates allow the epitaxial growth of the layered perovskite ferroelectric material, but favors simultaneously a perovskite second phase. On rock salt MgO, this perovskite can coexist with pyrochlore and/or fluorite phases, but is more easily eliminated than on STO. Finally, pure layered ferroelectrics SBN forms on SiO₂/Si, and Pt/Ti/SiO₂/Si, at the expense of film orientation loss.

Key Words:

• Ferroelectrics
• PZT
• SBN
• Thin Film
• Pulsed Laser Deposition: perovskite