Investigation of Coercive Field Shift During Cycling in HfZrOₓ Ferroelectric Capacitors

To fully understand the mechanisms for shifting of coercive field ( $E_{c}$ ) during the bipolar stress cycling in doped HfO₂ ferroelectric (FE) material, we present a systematic study with both characterization and simulation on HfZrOₓ (HZO) capacitor. First, with the help of time-dependent dielectric breakdown (TDDB) results, defect redistribution is found to be localized during the bipolar stress cycling. Then, with the advanced simulation framework GinestraⓇ, influences of work function (WF) mismatch of the electrodes and defect distribution on the $E_{c}$ symmetry and breakdown property are discussed. It indicates that the shift of $E_{c}$ is mostly due to the redistribution of defects from FE phase to non-FE phase and grain boundaries. Furthermore, nucleation limited switching (NLS) model is adopted to investigate the switching dynamics during coercive field shift in more detail.