Statistical study of RRAM MLC SET variability induced by filament morphology

This paper establishes the correlation between RRAM multilevel-cell (MLC) stochastic SET variability and random telegraph noise (RTN). We show that a smaller diameter (dD) of locally connecting/rupturing conductive filament (CF) and larger distance of gap (d _G ) between CF and electrode demonstrate both steeper Weibull slope β with a relaxed SET-disturb margin by 0.4 V and 36x improvement in RTN robustness. This is achieved by lower current compliances (I _coMp ) of 100 μA and larger RESET stopping voltage (V _reset ) of - 4.5 V for smaller d _D and larger do with leaving less residual oxygen vacancies (Vo ⁺² ) in the gap region. Results from the Kinetic Monte Carlo (KMC) modeling also support these findings.