Demonstration of Ferroelectricity in Al-Doped HfO₂ With a Low Thermal Budget of 500 °C

We report the experimental realization of ferroelectricity in Al-doped HfO
₂
(HAO) with the lowest reported thermal budget of 500 °C. A HAO film annealed at 500 °C for 30 s exhibits ferroelectricity with a remnant polarization (Pr) of 2.95 μC/cm
²
. The Pr increases to 10.40 μC/cm
²
when annealing duration is increased to 5 min, and approaches the values annealed at much higher temperatures of 700 to 1000 °C in other previous works. The presence of ferroelectricity has been confirmed by a series of typical phenomena, including the polarization-switched Positive-Up-Negative-Down measurement, the hysteretic polarization-voltage loop, and the butterfly-shaped C-V curves. In addition, comparable endurance characteristics are also obtained with other HfO
₂
-based ferroelectric films.