RTS noise characterization of HfOx RRAM in high resistive state

In this paper we analyze Random Telegraph Signal (RTS) noise and Power Spectral Density (PSD) in hafnium-based RRAMs. RTS measured in HRS exhibits fast and slow multilevel switching events. RTS characteristics are examined through novel color-coded time-lag plots and Hidden Markov Model (HMM) time-series analyses. Results are validated by comparing simulated and experimental PSD. Noise is examined at different reset conditions to provide an insight into the conduction mechanisms in HRS. Higher reset voltages are found to result in greater RTS complexity due to a larger number of active traps as confirmed by PSD.

► We characterize RTS in RRAM in high resistive state through color-coded time-lag plots and HMM.
► RTS features are correlated to the physical mechanism of conduction, assisted by the traps in the barrier.
► Power spectral analysis supports the proposed interpretation.
► Complex RTS is the superposition of two-levels RTS, confirming trap-assisted conduction model.
► In simplified conditions, we can extract the position of the main trap assisting conduction.