Correlative behavior between defect generation and ferroelectricity development in Hf0.5Zr0.5O2

Using electrical measurements and analysis, we investigated the relationship between the generation of defects in pristine Hf0.5Zr0.5O2 (HZO) metal-ferroelectric-metal (MFM) capacitor and their ferroelectricity. Applying a voltage to the HZO MFM capacitor for the first time, its current characteristics showed anomalous features, which differed from the typical ferroelectric characteristics observed in the second voltage application. In our previous research, we proposed the origin of this phenomenon as the generation of electric-field-induced defects in the HZO film, which mediated the current flowing through the MFM capacitor. In the present research, as a result of precise measurements of current-voltage characteristics, it was found that the defect density generated depended on the maximum electric field strength applied to the MFM. Similarly, with increasing defects, the ferroelectricity of the HZO was emphasized. Based on this relationship, we proposed a model in which electric field-induced defect generation initiated ferroelectric transformation in the HZO layer.