Structural changes and conductance thresholds in metal-free intrinsic SiOx resistive random access memory

Abstract

We present an investigation of structural changes in silicon-rich silicon oxide metal-insulatormetal resistive RAM devices. The observed unipolar switching, which is intrinsic to the bulk oxide material and does not involve movement of metal ions, correlates with changes in the structure of the oxide. We use atomic force microscopy, conductive atomic force microscopy, x-ray photoelectron spectroscopy, and secondary ion mass spectroscopy to examine the structural changes occurring as a result of switching. We confirm that protrusions formed at the surface of samples during switching are bubbles, which are likely to be related to the outdiffusion of oxygen. This supports existing models for valence-change based resistive switching in oxides. In addition, we describe parallel linear and nonlinear conduction pathways and suggest that the conductance quantum, G 0 , is a natural boundary between the high and low resistance states of our devices. V C 2015 AIP Publishing LLC. [http://dx

In situ transmission electron microscopy of resistive switching in thin silicon oxide layers

“…We have previously studied devices A biased with tungsten probes and have established that the resistance changes, and hence, structural modifications, are essentially the same as in devices B with a top contact [21]. Further details about the fabrication process can be found in Refs.…”

Review of Recently Progress on Neural Electronics and Memcomputing Applications in Intrinsic SiOx-Based Resistive Switching Memory

“…For example, several high temperature steps (>650°C) were done after PECVD SiO 2 deposition, namely: polysilicon deposition, thermal oxidation, and implant anneals, which might densify the SiO 2 layer, reduce the as-deposited defect levels, increase the soft breakdown threshold, and thus increase the filament formation energy during the subsequent electroforming process (resulting in forming voltage increase). Interestingly, the RESET voltage (the voltage at which LRS current begins to decrease) has been found to be greater than or equal to the SET voltage (where HRS current increases sharply), which is a unique characteristic of the SiO x -based ReRAM as compared to other materials systems [36,58]. The difference between RESET and SET voltages can potentially be controlled by optimizing the series resistance in the circuit, choice of electrode materials, and by doping effects that modulate the interfacial contact resistance [59].…”

Advanced physical modeling of SiO<inf>x</inf> resistive random access memories

“…4. Switching in silicon-rich silica RRAMs has been demonstrated experimentally by some of the authors [2]- [4], [13], reporting devices that can be cycled between high resistance OFF and low resistance ON states with a resistance contrast of at least 10,000, for a relatively long period. 5 shows the I-V characteristics and the variation of the peak temperature for an arbitrary initial vacancy distribution.…”

“…Applications of RRAM technology include high-density memories, novel processor architectures, neuromorphic computing and neural networks. Silica RRAM technology provides a further advantage, as it could be more easily integrated with Si CMOS chips [2]- [4].…”