Switching Dynamics in Metal-Ferroelectric HfZrO2-Metal Structures

The existence of negative capacitance (NC) and the switching dynamics of ferroelectric HfZrO2 (FE-HZO) metal-ferroelectric-Metal (MFM) structures are still contentious and unclear. Experiments with HZO MFM structures have yielded contradictory results. In this work, we perform a detailed study of the switching characteristics of HZO MFM structures. We have developed a pulse measurement setup that aims to minimize and carefully calibrate all circuit and sample parasitics. This allows us to isolate the intrinsic dynamic response of MFM FE-HZO structures. In contrast to other reports ON resistor-MFM (R-MFM) networks, no evidence of NC effect is observed over a broad range of conditions. Instead, in all cases, the extracted charge-voltage characteristics closely match the quasi-static hysteresis loop. In addition, we have confirmed that charge-voltage loops under the fast switching MFM configuration achievable in our experimental setup are consistent with those of R-MFM networks. Our study makes evident the crucial role of parasitics in the dynamic characterization of R-MFM circuits and the potential for misinterpretation of NC effects.

Automated summary

The existence of negative capacitance (NC) and the switching dynamics of ferroelectric HfZrO2 (FE-HZO) metal-ferroelectric-Metal (MFM) structures are still contentious and unclear. This work provides a detailed study of the switching characteristics of HZO MFM structures and demonstrates that there is no evidence of NC effect. The study emphasizes the crucial role of parasitics in the dynamic characterization of R-MFM circuits.