Low-Temperature Fabrication of BiFeO3 Films on Aluminum Foils under a N2-Rich Atmosphere.

To be CMOS-compatible, a low preparation temperature (<500 °C) for ferroelectric films is required. In this study, BiFeO₃ films were successfully fabricated at a low annealing temperature (<450 °C) on aluminum foils by a metal-organic decomposition process. The effect of the annealing atmosphere on the performance of BiFeO₃ films was assessed at 440 ± 5 °C. By using a N₂-rich atmosphere, a large remnant polarization (P_r~78.1 μC/cm² @ 1165.2 kV/cm), and a high rectangularity (~91.3% @ 1165.2 kV/cm) of the P-E loop, excellent charge-retaining ability of up to 1.0 × 10³ s and outstanding fatigue resistance after 1.0 × 10⁹ switching cycles could be observed. By adopting a N₂-rich atmosphere and aluminum foil substrates, acceptable electrical properties (P_r~70 μC/cm² @ 1118.1 kV/cm) of the BiFeO₃ films were achieved at the very low annealing temperature of 365 ± 5 °C. These results offer a new approach for lowering the annealing temperature for integrated ferroelectrics in high-density FeRAM applications.