On the bipolar resistive-switching characteristics of Al2O3- and HfO2-based memory cells operated in the soft-breakdown regime

Abstract

In this article, we investigate extensively the bipolar-switching properties of Al2O3- and HfO2-based resistive-switching memory cells operated at low current down to <1 μA. We show that the switching characteristics differ considerably from those typically reported for larger current range (>15 μA), which we relate as intrinsic to soft-breakdown (SBD) regime. We evidence a larger impact of the used switching-oxide in this current range, due to lower density of oxygen-vacancy (Vo) defects in the SBD regime. In this respect, deep resetting and large memory window may be achieved using the stoichiometric Al2O3 material due to efficient Vo annihilation, although no complete erasure of the conductive-filament (CF) is obtained. We finally emphasize that the conduction may be described by a quantum point-contact (QPC) model down to very low current level where only a few Vo defects compose the QPC constriction. The large switching variability inherent to this latter aspect is mitigated by CF shape tuning through adequate engineering of an Al2O3\HfO2 bilayer.

Spiking Neural Networks Based on OxRAM Synapses for Real-Time Unsupervised Spike Sorting

“…The experimental results (reduced I Reset , oxide dependent LRS, similar variability for LRS and HRS) may be explained by bulk switching and conduction mechanisms rather than filamentary ones (Chen et al, 2014; Goux et al, 2014) when very low I CC (<20 μA) are used. We believe that in this case the current conduction in the LRS is dominated by trap-assisted tunneling as is the case for the HRS (Wong et al, 2012).…”

Phase-Change and Redox-Based Resistive Switching Memories

“…On the other hand, researchers also started to see differences in the detailed behavior of the different oxide materials, while also interesting properties of cells made by stacking bilayers of these metal oxides are studied [76]- [78]. Also, the effect of dopants has been studied [79].…”

Excellent Roff/Ron ratio and short programming time in Cu/Al2O3‐based conductive‐bridging RAM under low‐current (10 μA) operation

“…For comparison, OxRRAM crossbar cells were integrated onto select transistor in a 1T1R circuit scheme. Three different cells were made using amorphous atomic‐layer‐deposited HfAlO (5 nm), Al 2 O 3 (1.6 nm)/HfO 2 (2.4 nm), or Ta 2 O 5 (5 nm), sandwiched between a TiN BE and either a Hf (10 nm) or a Ta (10 nm) TE .…”