Polymer-Assisted Solution Processing of TiO₂Thin Films for Resistive-Switching Random Access Memory

Abstract

In this study, we present a polymer-assisted solution (PAS) process to prepare TiO 2 electrolyte layers for resistive-switching random access memory (ReRAM). The PAS process utilizes the stability of metal-polymer complexes in the coating solution to form uniform and dense films. In addition, the viscosity of the PAS coating solution can easily be adapted for any currently used coating technique. The electrochemical-metallization-based (ECM-based) ReRAM devices were prepared by spin-coating the PAS coating solution on an indium tin oxide (ITO) glass substrate that is used as the bottom electrode. Cu was deposited on the PAS-TiO 2 electrolyte as an electrochemically active metal electrode used as the top electrode. The ECM-based ReRAM with the PAS-TiO 2 electrolyte layer demonstrated bipolar resistive-switching behavior with a memory window wider than 13, cycle endurance over 500 cycles, and retention time longer than 10 4 s. Analysis of the conduction mechanism in high and low resistive states indicates that the resistive switching is attributed to the formation and rupture of Cu conducting filaments (CFs) in the PAS-TiO 2 electrolyte layer. New nonvolatile memory devices with various material characteristics based on ferroelectric polarization, magnetic polarization, and material phase change have been investigated to overcome the scalability issue of modern flash memory devices.1-3 However, recent research efforts have focused on resistive-switching random access memory (ReRAM), also known as conductive-bridge random access memory (CBRAM) or electrochemical-metallization-based (ECMbased) ReRAM, due to its outstanding advantages including a simple structure, low switching power consumption, fast switching speed, and capability of both unipolar and bipolar switching modes.4-6 ECMbased ReRAM consists of a solid electrolyte thin film in between two electrodes, an electrochemically active metal (EAM) electrode such as Ag or Cu and an electrochemically inert metal (EIM) electrode such as Pt, Au, or W. The EAM, biased with a sufficiently positive-polarity voltage with respect to the counter electrode (EIM), is electrochemically dissolved and migrates through the solid electrolyte toward the EIM electrode. Consequently, a conducting bridge forms between the two electrodes, which is also known as a conducting filament (CF). The resistive switching in the ECM-based ReRAM relies on the formation (SET) and rupture (RESET) of the CFs in the solid electrolyte, which depend on the polarity of the applied voltage. 7,8 Various solid electrolyte materials such as perovskites, chalcogenides and metal oxides have been explored for the fabrication of ReRAM.9-21 Most solid electrolyte films have been deposited using vacuum based processes such as thermal oxidation, atomic layer deposition, pulsed laser deposition, sputtering, and thermal evaporation. 15,19,[22][23][24] There are also other efforts devoted to growing metal oxide films as the solid electrolyte layers using chemical solution deposition such as sol-gel process. 25,26 H...

A Conjugated Polymer Bearing Perylenediimide (PDI) and Ferrocene (Fc) Exhibiting Stable Data‐Storage Performance

“…[9][10][11][12][13][14][15][16][17][18][19] Among which, polymeric material has attracted more attentions due to its typical advantages as solution processability, structural tunability, three-dimension stacking, largescale flexibility, etc. [20][21][22][23][24][25] In the early research of polymeric ReRAM, the materials as poly(N-vinylcarbazole) (PVK), [26][27][28] polystyrene (PS), [29][30][31] polymethylmethacrylate (PMMA), [32][33][34][35] poly(vinylidene chloride) (PVC), [30] and polyvinylfluoride (PVF) [36] were frequently chosen as active-layers to fabricate aluminum/polymer/aluminum (Al/polymer/Al) structured devices, and filament formation mechanism was proposed to interpret the switching behaviors. [37][38][39] However, the formation of metal filament is not the intrinsic characteristics of these polymers, which in turn is resulting from the physical damages of the devices.…”

“…[ 9–19 ] Among which, polymeric material has attracted more attentions due to its typical advantages as solution processability, structural tunability, three‐dimension stacking, large‐scale flexibility, etc. [ 20–25 ]…”

Enhancement of resistive switching properties in Al2O3bilayer-based atomic switches: multilevel resistive switching

“…An atomic switch is considered as a suitable candidate to replace dynamic random-access memory (DRAM) or FLASH memory devices in modern computing and information technology due to its high-speed read/write access (∼10 ns, like DRAM devices) and capability to recollect data when the power supply is off (non-volatile; like FLASH memory devices) [1][2][3]. Atomic switches are also attractive because of their simple design, with a dielectric layer (polymer materials, perovskites, metal halides, and various classical transition-metal oxides) [4][5][6][7][8] packed between an electrochemically active top electrode (Cu, Ag) and electrochemically inert (Pt, W, ITO, etc,) bottom electrode [9][10][11][12]. The resistive switching (RS) in an atomic switch depends on the growth of the conductive filament (CF) and can be verified by the electro-redox (cation migration is driven by the electric field) process or in situ investigation by transmission electron microscopy and conductive atomic force microscopy (C-AFM) [13][14][15].…”

Effect of dysprosium and lutetium metal buffer layers on the resistive switching characteristics of Cu–Sn alloy-based conductive-bridge random access memory

“…In recent years, conductive-bridge random access memory (CBRAM) devices have been intensively investigated as an exciting alternative for next-generation memory devices because of their high switching speed, low power consumption, high on/off ratio, and complementary metal oxide semiconductor compatibility [1][2][3]. The resistive switching (RS) of CBRAM is defined by the formation/dissolution of the conductive filament (CF), which acts as a bridge between the electrochemically active metal electrode (Cu, Ag) and the inert bottom electrode (Pt, W) [4][5][6]. However, uncontrolled growth of the CF leads to poor RS performance.…”