Demonstration of Ferroelectricity in Al-doped HfO2 with a Low Thermal Budget of 500 °C

Abstract

We report the experimental realization of ferroelectricity in Al-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The Pr increases to 10.40 μC/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> 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 <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based ferroelectric films.