Multilayer Metal‐Oxide Memristive Device with Stabilized Resistive Switching

Abstract

nanoelectronic devices with the effect of resistive switching, which consists in a reversible change of resistance in response to electrical stimulation [5] and is identified with the memristive effect. [6] Despite the significant progress in understanding of the memristive effect and approaching maturity of the technology of resistiveswitching devices over the last 10 years, there are still a number of fundamental problems to solve.A key problem on the way of using resistive-switching devices as programmable elements in memory devices and mixed analog-digital processors of new generation is the variability of resistive switching parameters inherent to memristive thin-film devices. [7] Achieving stable switching between the nonlinear resistive states is also an important task on the way to implementing large passive crossbar arrays of memristors and solving the problem of leakage currents in them. [8,9] Metal-oxide memristive devices are most compatible with the traditional complementary metal oxide semiconductor (CMOS) process and exhibit a valence change memory effect. [10] The variation of switching parameters in such devices is caused by the stochastic nature of migration of oxygen ions and/or vacancies responsible for the local oxidation and recovery of conductive channels (filaments) and is accompanied by the degradation of switching parameters in the case of uncontrolled oxygen exchange between the dielectric and electrode materials.The traditional approaches to control the reproducibility of resistive switching include the formation of special electric field concentrators [11][12][13] and appropriate selection of materials/interfaces in memristive device structure. In the latter case, bilayer or multilayer structures are formed, in which the switching oxide alternates with a barrier/buffer layer (layers) to control the migration of oxygen vacancies, [14,15] with a layer of low dielectric constant [16,17] to obtain nonlinear currentvoltage (I-V) characteristics, or with a layer of higher/lower thermal conductivity [18,19] for the removal/retention of heat in the switching area and to achieve analog switching character. To tune the resistive states with given accuracy, regardless of

Pseudo-Interface Switching of a Two-Terminal TaOx/HfO2 Synaptic Device for Neuromorphic Applications

“…One representative memristor, oxide-based resistive switching memory, has been studied in depth due to its excellent performance in terms of endurance, retention, reliability, reproducibility, and compatibility with complementary metal oxide semiconductors (CMOSs) [10][11][12][13]. To date, reversible resistive properties have been reported using a large number of oxides.…”

Improved Pulse-Controlled Conductance Adjustment in Trilayer Resistors by Suppressing Current Overshoot

“…The peak intensity that is located at about 99.5 eV is higher at the deeper etching level (level 11) than it is at level 7. This indicates that the Si substrate is more exposed by X-ray beams at the deeper etching level (level 11) [ 21 ]. Moreover, the peak point at etch level 11 is shifted to the right compared to that at etch level 7, indicating that the Si–O bond located at 103.5 eV is increased at level 11 [ 25 ].…”

“…The SiO 2 layer can be easily formed when using silicon substrate as the bottom electrode and different methods such as native oxide, thermal oxide, and chemical vapor deposition (CVD). Another advantage of inserting the tunnel barrier with a high band gap is a reduction in the LRS current [21,22]. To employ the advantageous tunnel barrier in resistive switching, the insulating property of the SiO 2 layer is maintained after the forming and set processes.…”

“…However, the metal–oxide–semiconductor structure has other advantages, such as self-rectification and low-power operation. The most effective way to enhance resistive switching is to design multiple dielectric stacks [ 21 ]. The use of an oxygen reservoir, such as a TiO x layer, is popular in metal–oxide-based resistive switching memory.…”

Facile Approach for Improving Synaptic Modulation of Analog Resistive Characteristics by Embedding Oxygen Vacancies‐Rich Sub‐TaOx in Pt/Ta2O5/Ti Device Stacks

“…To modulate the movement of oxygen ions or vacancies for gradual analog states effectively, various nanoscale engineering techniques that are elaborate and use nanocrystal structures, electrode shape engineering, and electrode interface have been reported. [17,[25][26][27][28] However, the aforementioned methods are not practical, because they involve complex manufacturing steps and are vulnerable to device reliability. Thus, it is extremely necessary to obtain a reliable Ta 2 O 5 -based resistive synaptic device that has both facile nanoscale engineering processability and in situ controllability.…”