Role of charge injection/de-trapping in imprint behavior of ferroelectric Hf0.5Zr0.5O2 thin film

Abstract

Ferroelectric HfO2-based thin films have attracted increasing interest due to their potential applications in nonvolatile memory areas. However, their unique properties, such as imprint, lead to serious reliability issues. In this study, the origin of imprint behavior is investigated by using TiN/Hf0.5Zr0.5O2 (10 nm)/TiN MFM capacitors. By modulating the internal electric field during imprint, we discover that charge injection/de-trapping in metal–ferroelectric interfaces plays an essential role in imprint behavior rather than charge movement inside the FE layer. The asymmetric shift of the coercive field is also discussed, which is attributed to nonlinear interaction between polarization's bound charges and the electrode's screening charges. This suggests that controlling interface quality should effectively suppress imprint in HfO2-based thin films.