Electric field cycling-mediated variations in defect distributions associated with wake-up and split-up behaviors of a ferroelectric Si-doped HfO2 thin film

We report variations in the characteristic ferroelectric switching time and interface free carrier concentration associated with wake-up and split-up behaviors of a 4.2 mol. % Si-doped HfO2 thin film. Prior to the development of the split-up behavior, the thin films exhibited the wake-up behavior; the remanent polarization increased on repeated electric field cycling. After the wake-up behavior, Si-doped HfO2 films exhibited degradation of the remanent polarization values and splitting of the ferroelectric switching current peaks when a lower electric field was swept; this is referred to as the split-up behavior. An investigation of the ferroelectric switching dynamics revealed retardation, followed by recovery, of the characteristic switching time for ferroelectric nucleation, coincident with the wake-up and split-up behaviors, respectively. We analyzed the interface free carrier concentration from capacitance–voltage characteristics and revealed that the wake-up and split-up behaviors were associated with changes of numbers of defects as electric field cycling continued.