Bipolar and Unipolar Cycling Behavior in Ferroelectric Scandium-doped Aluminum Nitride
Li Chen, Chen Liu, Minghua Li, Wen‐Dong Song, Weijie Wang, Zhixian Chen, Subhranu Samanta, Hock Koon Lee, Yao Zhu
Abstract
Ferroelectric scandium-doped aluminum nitride (Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf> Sc <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> N) has triggered tremendous research interests on account of the discovery of its superior ferroelectricity. Initial studies suggest that the Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf> Sc <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> N may suffer from large leakage current and poor endurance, which may hinder its further thickness scaling and long-term reliability. In this work, we study the evolution of leakage current of the ferroelectric Al <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.7</inf> Sc <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</inf> N-based capacitor by bipolar and unipolar cycling tests. We observe that the leakage current dramatically increases only when the device undergoes bipolar cycling with the pulse amplitude larger than coercive electric field, and the Al0.7Sc0.3N film occurs grain fragmentation, which are caused by the polarization switching.