Robust OS-FeFETs with Crystallized Anatase-TiO₂ Channel-Hafnia Ferroelectric Layer Stack for Integration of 3D Memory Applications

In this study, the planar and vertical OS-FeFETs were fabricated based on a stack of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TiO}_{2}$</tex>-channel/HfLaO ferroelectric layers without thermal budget mismatch. The fabricated FeFETs demonstrate exceptional performance and robust stability, including: 1) Memory properties with an on/off ratio exceeding 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup>, a memory window of over 1V, and endurance surpassing 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8</sup> cycles; 2) High-temperature operational stability up to 475K and resistance to ambient exposure for over a year. The excellent memory performances and thermal-stability achieved in OS-FeFETs could be owed to material- and process-compatibility between the crystalized <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{TiO}_{2}$</tex> channel/HfLaO ferroelectric layers that results in a thermally-stable stack with negligible interfacial interdiffusion.