Accurate Picture of Cycling Degradation in HfO<sub>2</sub>-FeFET Based on Charge Trapping Dynamics Revealed by Fast Charge Centroid Analysis
Reika Ichihara, Y. Higashi, Kunifumi Suzuki, Keisuke Takano, Yoko Yoshimura, Takamasa Hamai, Kota Takahashi, Kazuhiro Matsuo, Yasushi Nakasaki, Masamichi Suzuki, Yuuichi Kamimuta, Masumi Saitoh
Abstract
We establish an accurate picture of cycling degradation in HfO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> -FeFET based on the dynamics of various kinds of trap charges (e:electron/h+:hole, stable/unstable, program-induced/read-induced) revealed by fast charge centroid analysis. A part of e trapped at HfO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> /SiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> interface, which is unrelated to ferroelectricity and unstable before the cycling degradation, becomes unrecoverable after cycling. By calculating its impact on Vth, of FeFET and clarifying the behavior of spontaneous polarization during cycling, we found that the amount of h+-trapping increases with cycling. This additional h+-trapping, which is accompanied with erase operation and disappears with program operation, is the most critical factor for Vth, window narrowing and accelerated by cycling-induced unrecoverable trapped e. Not only e-trapping but also its stabilization should be suppressed for higher endurance.