Electrical cycling induced evolution of internal resistance and interfacial capacitance distributions in PZT thin-film capacitors

초록

Ferroelectrics have attracted academic and industrial interest owing to their functional properties. However, their reliability is often degraded by fatigue under repeated electrical cycling. In this study, we investigate the evolution of defect-related internal resistance and interfacial capacitance in PbZr0.52Ti0.48O3 (PZT) thin-film capacitors by combining first-order reversal curve (FORC) analysis with a switching-current circuit model. The proposed framework provides distributions of internal resistance and interfacial capacitance and tracks their evolution during electrical cycling. The FORC results reveal a gradual reduction in the overall switching density accompanied by a narrowing of the coercive-voltage distribution and a shift of the internal-bias distribution toward zero, indicating a selective suppression of switching events under extreme local conditions. In addition, the average internal resistance exhibits a clear correlation with leakage current, while the interfacial capacitance decreases monotonically with cycling, which is interpreted as an increase in the effective oxide thickness. This purely electrical analysis provides quantitative insight into fatigue-induced inhomogeneous degradation in PZT thin-film capacitors and can be extended to other ferroelectric material systems.

키워드