Temperature-Dependent Subcycling Behavior of Si-Doped HfO₂ Ferroelectric Thin Films

The involvement of unwanted subcycling behavior in endurance cycling of HfO2-based ferroelectric thin films is detrimental to the reliability performance of nonvolatile memory devices. Subcycling is also critical for emerging neuromorphic applications as well as multilevel memory cells, which are deliberately operated in subloops of the polarization hysteresis. There is a substantial mismatch between the proven application potential and the lack of basic studies on subcycling behavior. In this work, the temperature-dependent subcycling behavior of a 5 mol % Si-doped HfO2 ferroelectric thin film is investigated by carefully comparing the evolution of P–E and I–E hysteresis loops during subcycling at 80–350 K. The switching density distributions before and after 108 subcycles at various temperatures are characterized using first-order reversal curve measurements to reveal the changes in the coercive field and internal bias fields. Based on a defect segregation-induced local bias field model, the establishment of different local bias fields during subcycling and its temperature dependence are thoroughly discussed.