Unraveling Fatigue Mechanisms in Ferroelectric AlScN Films: The Role of Oxygen Infiltration
Ruiqing Wang, Jiuren Zhou, Danyang Yao, Siying Zheng, Bochang Li, Xiaoxi Li, Yan Liu, Yue Hao, Genquan Han
Abstract
Confronting the endurance challenge in wurtzite ferroelectrics, this study provides a pioneering microscopic investigation into the fatigue mechanisms of AlScN films, identifying oxygen infiltration as the key factor. Utilizing transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS), we dynamically tracked the redistribution of oxygen elements within Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.65</sub> Sc <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.35</sub> N films during electrical stress cycling. Results reveal that prolonged stress cycling drives oxygen penetration along the grain boundaries into the bulk, leading to fatigue [Fig. 1]. Importantly, removing the oxygen source effectively suppresses oxygen infiltration, achieving an impressive endurance of 4.6×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sup> cycles under a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sub> of 114.6 μC/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . These insights are pivotal for developing next-generation ferroelectric memory devices with superior endurance properties