Add to ORKGResistive switching memory (RRAM) attracts a growing research interest as potential high-density Flash replacement. Although several transition metal oxides have shown resistance switching capabilities, NiO is considered one of the most promising materials due to its stable and unipolar switching [1]. However, the scalability and variability of the programming currents and voltages are still a matter of concern. This work provides a comprehensive understanding of set/reset properties of NiO-based RRAM. The relationship between active-filament size and programming current/voltage is studied by physical modeling of thermally-driven reset and field-driven set transitions [2]. The developed models may serve as numerical/analytical design t...