As ferroelectric Hf_0.5Zr_0.5O₂ (HZO) thickness scales below 10 nm, the switching characteristics are severely distorted typically showing an antiferroelectric-like behavior (pinched hysteresis) with reduced remanent polarization. Using Landau-Ginsburg-Devonshire (LGD) theory for the analysis of the experimental results, it is shown here that, in thin (5 nm) HZO, depolarization fields drive the system in a stable paraelectric phase coexisting with a metastable ferroelectric one, which explains the pinched hysteresis. This state of matter resembles a first order ferroelectric above the Curie temperature which is known to result in similar double-loop behavior. Here, based on the analysis of experimental data in the framework of LGD theory, it is reported that charge injection and trapping at pre-existing interface defects during field cycling (“wake-up”) screens the depolarization field stabilizing ferroelectricity. It is found in particular that a sufficiently large energy density of interface states is beneficial for the recovery of fully open ferroelectric loops.

作为铁电体 Hf _0.5 Zr _0.5 O ₂(HZO) 厚度小于 10 nm，开关特性严重失真，通常表现出类似反铁电体的行为（收缩磁滞），剩余极化减少。使用 Landau-Ginsburg-Devonshire (LGD) 理论分析实验结果，这里表明，在薄 (5 nm) HZO 中，去极化场驱动系统处于与亚稳态铁电相共存的稳定顺电相中，解释了受压滞后。这种物质状态类似于居里温度以上的一阶铁电体，已知会导致类似的双回路行为。在此，基于在 LGD 理论框架下对实验数据的分析，据报道，在场循环（“唤醒”）期间在预先存在的界面缺陷处注入和捕获电荷会屏蔽去极化场稳定铁电体。特别发现，足够大的界面态能量密度有利于完全开放的铁电环的恢复。