Enhanced resistive switching characteristics in Al₂O₃memory devices by embedded Ag nanoparticles

Abstract

In this paper, AlO/Ag/AlO sandwiched thin films were deposited by magnetron sputtering. AlO thin films with embedded Ag nanoparticles (AgNPs) have been fabricated by adopting appropriate experimental parameters. The measurements on the resistive switching behaviors demonstrated that the embedded AgNPs could substantially enhance the local electric field, and effectively reduce the switching voltages, resulting in a sharply increased OFF/ON ratio up to 10 at 0.5 V. Furthermore, the cycling stability was considerably improved owing to the reduced randomness for the formation and rupture of conductive filaments (CFs). AgNPs could also contribute with movable Ag ions, and the Ti top electrode usually reacts with AlO promoting the formation of oxygen vacancies. As a result, a hybrid CF with better high-temperature stability was induced. Comparatively, if the embedded Ag sublayer is smooth, the switching parameters become dispersive owing to the random formation and rupture of CFs, and the switching performance is deteriorated. A physical model was proposed to understand the effect of the embedded AgNPs.

Toward Controlling Filament Size and Location for Resistive Switches via Nanoparticle Exsolution at Oxide Interfaces

“…In the case of Ag or Cu nanoparticles, metal ions often migrate into the oxide during operation, actively taking part in the switching mechanism. [7,26,39,44] For noble metals, it is often assumed that the nanoparticles serve predominantly to enhance the local electric field. Just like movement of metal cations can participate in switching, oxygen anion exchange with the electrodes can benefit the stability of the switching process.…”

“…In order to address the challenge of stochastic filament location, several strategies have been put forward to spatially confine filaments either in the switching or electrode materials. These include 1) switching within a single dislocation in SrTiO 3 [9] and in SiGe, [10] 2) fabricating electrodes into tips, [11][12][13][14][15][16][17][18] 3) integrating nanoporous graphene into the switching material, [19][20][21][22] 4) embedding nanoparticles into the switching material, [23][24][25][26][27][28][29][30][31][32][33] 5) introducing nanoparticles at the metal-oxide interface, [34][35][36][37][38][39][40] and 6) engineering the edges of the devices, which has been shown to be industrially viable. [41] These strategies are analyzed in terms of their opportunities, processing challenges and materials universality in Table 1, and summarized through device [35] sketches in Figure 1a.…”

Effect of Annealing Temperature for Ni/AlOx/Pt RRAM Devices Fabricated with Solution-Based Dielectric

“…Figure 5b shows a schematic representation of this process consisting of ON and OFF states, which is considered as the switching mechanism of these devices. The formation and rupture process of CF is associated with the distribution of oxygen ions and oxygen vacancies in the TE and RS layer [22,48,57,58,59]. Figure 5b(i) shows the initial state of RRAM devices without applied voltage, indicating oxygen atoms present in the AlO x thin film.…”

Recent Progress in Synaptic Devices Paving the Way toward an Artificial Cogni‐Retina for Bionic and Machine Vision

“…These memristors help to reduce operating voltages and provide better retention and higher on/off ratios due to localization of electric fields. Some examples are based on Ag, Au, and Hf…”