Noise-Induced Resistance Broadening in Resistive Switching Memory-Part II: Array Statistics

Noise in resistive switching memory (RRAM) is among the main concerns due to its impact on the reliability of single-bit and multilevel cell devices. Although noise in typical RRAM cells is understood fairly well, the statistics of noise and the presence and impact of statistical tails in the current fluctuation is what mostly affects the RRAM reliability at the array level. This paper addresses current noise in RRAM arrays, focusing on high-resistance state distribution and its broadening with time. We highlight two main contributions to the tail behavior, namely, random walk (RW) and random telegraph noise (RTN) with random start and stop. We provide evidence for a time decay of RW amplitude with time, which we explain by time-dependent stabilization of defects. We finally develop a statistical Monte Carlo model for noise, which is capable of explaining the broadening of the resistance distribution based on a physical description of RW and RTN components.