Pinning model of wake-up and fatigue in Hf-based ferroelectrics

Abstract

We provide evidence of domain pinning as the main contribution to early fatigue, i.e. the loss of remnant polarization (PR) with field cycling in ferroelectric (FE) La-doped hafnium zirconium oxide capacitors. Additionally, depinning is strongly linked to wake-up, the initial increase of PR with cycling, and fatigue recovery. Deeper understanding of (de)pinning is crucial for tackling reliability questions related to FE endurance. We provide an empirical model capable of capturing the PR changes with cycling due to (de)pinning. The model accurately describes the evolution of the full polarization-field loop with a single mechanism. It is calibrated and verified for a wide range of cycling fields and number of cycles and provides better extrapolations than the common linear one.