Understanding pulsed-cycling variability and endurance in HfO<inf>x</inf> RRAM

Abstract

Resistive switching memory (RRAM) devices based on metal oxides are receiving strong interest for future highdensity stand-alone memories and storage class memories. To explore possible applications of RRAM, the set/reset variability and cycling endurance must be addressed and understood. This work shows a comprehensive study of pulsed-operated variability and endurance in HfO x-RRAM. We analysed the dependence of switching variability on operation current, voltage and pulsewidth, providing guidelines to optimize set/reset distributions in oxide RRAM. The impact of pulse-amplitude and pulse-width on cycling endurance is then discussed. The results are explained by a new physics-based model for endurance controlled by defect injection from the bottom electrode during reset.

Reduction of the Cell-to-Cell Variability in Hf1-xAlxOyBased RRAM Arrays by Using Program Algorithms

“…Compared to recently reported distributions [6,8], the window between HRS and LRS is well defined and the cellto-cell as well as the cycle-to-cycle variability is strongly reduced.…”

Programming Pulse Width Assessment for Reliable and Low-Energy Endurance Performance in Al:HfO2-Based RRAM Arrays

“…Afterwards, 1k reset/set cycles were performed on every batch of 128 RRAM devices in order to test the switching endurance for every pulse width considered. As shown in Figure 3, it can be concluded that the voltage amplitude required to switch the RRAM devices increases when the programming pulse width is reduced [21,22]. This increase is even more noticeable when pulse widths of 100 and 50 ns are used.…”

“…Such a good performance achieved regardless the pulse width employed could be explained as follows. According to Balatti et al [21], there is an optimal combination of the programming pulse width and the voltage amplitude in order to achieve the best switching endurance. The step-by-step approach implemented in the core of the ISPVA leads to a dynamic tailoring of this combination of the two programming parameters (see Figure 3) every cycle.…”

A Study of the Variability in Contact Resistive Random Access Memory by Stochastic Vacancy Model

“…However, there are still many obstacles to be overcome to easily implement RRAM memory arrays in current state-of-the-art CMOS circuits [ 5 , 6 ]. One of the key challenges in sizable RRAM array is found in the variation existing between and within cells [ 7 – 10 ]. Many models and simulations have been proposed to describe the stochastic generation/recombination process of oxygen vacancy (Vo-) in transition metal oxide (TMO) film [ 11 – 14 ].…”