Dopant Engineering of Hafnia‐Based Ferroelectrics for Long Data Retention and High Thermal Stability

Abstract

AbstractHafnia‐based ferroelectrics have gained much attention because they can be used in highly scaled, advanced complementary metal‐oxide semiconductor (CMOS) memory devices. However, thermal stability should be considered when integrating hafnia‐based ferroelectric transistors in advanced CMOS devices, as they can be exposed to high‐temperature processes. This work proposed that doping of Al in hafnia‐based ferroelectric material can lead to high thermal stability. A ferroelectric capacitor based on Al‐doped hafnia, which can be used for one‐transistor‐one‐capacitor applications, exhibits stable operation even after annealing at 900 °C. Moreover, it demonstrates that the ferroelectric transistors based on Al‐doped hafnia for one‐transistor applications, such as ferroelectric NAND, retain their memory states for 10 years at 100 °C. This study presents a practical method to achieve thermally stable ferroelectric memories capable of enduring high‐temperature processes and operation conditions.