Noise spectroscopic study of resistive switching in HfO₂memristor

Hafnium oxide (HfO₂)-based memristors are promising candidates for next-generation memory and neuromorphic devices owing to their CMOS compatibility and stable resistive switching. However, microscopic resistive mechanisms behind the switching variability and defect dynamics in oxides are still not understood. In this study, electrical transport and ultra-low-frequency noise spectroscopy were employed to investigate electrical transport and switching behavior in thin films of HfO₂ devices prepared on a 300 mm Si wafer. Current-voltage measurements show reproducible bipolar switching with well-defined high and low resistance states. Noise spectroscopy reveals strongly enhanced current fluctuations near the set and reset voltages, consistent with the formation and rupture of conductive filaments driven by oxygen vacancy migration. The power spectral density exhibits 1/f behavior in stable states, while pronounced noise peaks emerge during switching, pointing to defect redistribution and stochastic transport. Furthermore, multiple resistive states, exhibiting stable behavior and low noise, can be readily programmed by varying the reset voltage. The studies probe defect activity and conduction pathways in HfO₂ memristors, providing microscopic insights essential for improving switching stability and enabling multi-level memory and neuromorphic applications. The transport measurements are supported by NSF-MRI award 1726303.