Nucleation suppression by charge screening on grain boundaries: a kinetic model for bulk imprint in polycrystalline ferroelectric thin films

TL;DR

This paper presents a phase-field model showing how charge screening at grain boundaries suppresses nucleation, leading to bulk imprint in ferroelectric thin films, which impacts memory reliability.

Contribution

It introduces a novel bulk imprint mechanism considering grain boundary effects, advancing understanding beyond traditional interface-focused models.

Findings

Charge screening at grain boundaries suppresses domain nucleation.

The model aligns with experimental trends of imprint behavior.

Provides new insights into ferroelectric memory reliability.

Abstract

The imprint effect, a significant reliability challenge in ferroelectric memories, manifests as a shift in the coercive field during retention and endurance tests, ultimately degrading the usable memory window. \rv{While traditional models attribute imprint primarily to charge screening at the interface between the dead layer and the ferroelectric film, the contribution from grain boundaries has been largely overlooked. This work advances a bulk imprint mechanism by establishing a phase-field model, which demonstrates that the tuning of domain nuclei near grain boundaries via charge screening consistently explains the imprint process and aligns with key experimental trends.} These findings provide novel insights into the imprint process and advance the understanding of reliability issues in ferroelectric memory devices.