In Situ TEM and Energy Dispersion Spectrometer Analysis of Chemical Composition Change in ZnO Nanowire Resistive Memories

Abstract

Resistive random-access memory (ReRAM) has been of wide interest for its potential to replace flash memory in the next-generation nonvolatile memory roadmap. In this study, we have fabricated the Au/ZnO-nanowire/Au nanomemory device by electron beam lithography and, subsequently, utilized in situ transmission electron microscopy (TEM) to observe the atomic structure evolution from the initial state to the low-resistance state (LRS) in the ZnO nanowire. The element mapping of LRS showing that the nanowire was zinc dominant indicating that the oxygen vacancies were introduced after resistance switching. The results provided direct evidence, suggesting that the resistance change resulted from oxygen migration.

Memristive behavior of Al2O3 film with bottom electrode surface modified by Ag nanoparticles

“…Resistive random access memory (RRAM) devices have attracted considerable attentions due to its advantages of simple structures, rapid programming speed, high areal density, low power consumption and long retention time [1][2][3][4][5], and it is proposed as a potential next-generation candidate for nonvolatile memory. Various materials presenting resistive switching characteristics have been reported, including transition metal oxide materials (TMO), such as NiO, ZrO 2 , ZnO, TiO 2 , HfO 2 , Nb 2 O 5 , Cu x O [5][6][7][8][9][10], chalcogenides, perovskite oxides and organic materials [11][12][13].…”

“…Various materials presenting resistive switching characteristics have been reported, including transition metal oxide materials (TMO), such as NiO, ZrO 2 , ZnO, TiO 2 , HfO 2 , Nb 2 O 5 , Cu x O [5][6][7][8][9][10], chalcogenides, perovskite oxides and organic materials [11][12][13]. Recently, researchers have extensively studied TMO materials, on account of the easy control of their chemical composition, low fabrication cost and completely compatibility of the current complementary metal oxide semiconductor (CMOS) processes.…”

Transmission Electron Microscopy on Memristive Devices: An Overview

“…Other systems where such a behavior has been observed are ZnO (Chang et al, 2008;Chen et al, 2013;Huang et al, 2012Huang et al, , 2013Song et al, 2011;Yao et al, 2012), NiO (Seo et al, 2004), CuO (Dong et al, 2007), HfO 2 SrTiO3 (Szot et al, 2006). It should be noted here, that the distinction between a phase change in PCM cells is not only caused by diffusion-less phase changes but can also include diffusion, e.g.…”

Single-crystalline CuO nanowires for resistive random access memory applications

“…3 On the other hand, when both electrodes are inert metals, such as Au or Pt, the anion migration in the insulator will lead to resistive switching. 4 The conducting filament will be composed of oxygen vacancies, called the valence change mechanism (VCM), 3 although the mechanism is still unclear in many dielectric layers.These different type of conducting filaments have been observed in recent years; for example, the real time observation of the Zn structure filament in the ZnO dielectric layer 5 and the Ti 4 O 7 filament of in the TiO 2 layer 6 in a VCM system. The active metal type filament can generate a conducting bridge in various dielectric layers in an ECM system.…”

“…3 On the other hand, when both electrodes are inert metals, such as Au or Pt, the anion migration in the insulator will lead to resistive switching. 4 The conducting filament will be composed of oxygen vacancies, called the valence change mechanism (VCM), 3 although the mechanism is still unclear in many dielectric layers.…”