N Penetration Enhances Vacancy Filling, Al/Sc-N Bonding, and Ferroelectric Properties in AlScN Films
Xuefeng Yang, Bochang Li, Jiuren Zhou, Xiaoxi Li, Siying Zheng, Yan Liu, Yue Hao, Genquan Han
Abstract
We demonstrate, for the first time, that nitrogen(N) penetration into AlScN films significantly enhances ferroelectric performance by suppressing N vacancies and increasing grain size. This is achieved by introducing N from a TiN bottom electrode. As a result, we achieve a remnant polarization (<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 150 μC/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, a notable reduction in leakage current, and a high breakdown-to-coercive field ratio (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</sub>/<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">E</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub>) of 1.85. Material analysis shows that N from the TiN electrode fills N vacancies, suppresses oxidation, and improves the crystalline quality of AlScN, the AlScN/TiN interface, and overall ferroelectric performance. This simple yet effective N treatment strategy advances AlScN material properties and enables next-generation ferroelectric electronics.