(Invited) Polarization Stability Improvement for Hf0.5Zr0.5O₂-Based Ferroelectric Capacitor

The instability in polarization during the endurance test of Hf 0.5 Zr 0.5 O 2 (HZO) ferroelectrics thin films including the wake-up and the fatigue are still major challenges for the development of HZO-based ferroelectric memories. In this work, we will review the proposed mechanisms of the instabilities in polarization including wake-up and fatigue of the HZO-based metal-ferroelectric-metal (MFM) capacitors. Then, the material processing techniques to address the issues of instabilities are provided. The in-situ deposition of electrode and ferroelectric layers by atomic layer deposition (ALD) attracted considerable attention as a promising solution. Owing to the improved interface quality, both the endurance characteristics and remanent polarization were enhanced. We have also developed a HfO 2 /ZrO 2 superlattice structure to further enhance the ferroelectric endurance of the MFM capacitors. The superlattice MFM capacitors show wake-up free characteristics with excellent endurance. The device performances and endurance characteristics of ferroelectric thin film transistor will also be presented.