The structure and ferroelectric property of La-doped BiFeO3/SrTiO3 artificial superlattice structure by rf sputtering: Effect of deposition temperature

Improvement of ferroelectric property by Lanthanum (La)-doping of BiFeO3 (BFO) and strain effect of high quality superlattice films deposited at temperature ≧ 700 °C was shown in this study. The in-pane (200) radial scans showed that films at deposition temperature above 700 °C behaved high strained ~−1.4% and showed epitaxity properties. The La-doped BFO superlattice structure also behaved higher polarization value ~ 197 μC/cm2 and lower leakage current density comparing with BFO superlattice structure shown in our previous study. The ferroelectric properties of superlattice structures are enhanced by lattice strain and strongly correlated with the defect state of films.

► We deposited high quality La-doped BFO/STO superlattice structures.
► La-doped BFO/STO superlattice films have stable deposition rate.
► La-doping of BFO enhanced the ferroelectric and leakage properties.
► Ferroelectric properties correlated with crystal quality, strain and defect state.