On the Variability of HfOx RRAM: From Numerical Simulation to Compact Modeling

X. Guan, S. Yu, H.-S.P. Wong
Stanford University, US

Keywords: resistive switching, memory, hafnium oxide, variation


The trap-assisted conduction and filamentary switching mechanisms of the HfOx based resistive memory are studied. A numerical simulator is developed to reproduce the experimental I-V curves. Comparison with experiments shows that the cycle-to-cycle variation in the RRAM is mainly due to the variation in the gap distance between the filament tips and the electrode. A set of analytical equations suitable for compact modeling is then derived to capture the switching behavior of metal oxide-based RRAM (OxRRAM). Through the introduction of random perturbations of the gap size, the model successfully reproduces the measured resistance variation of the multi-level RRAM cell.