Oxygen Concentration Effect on Conductive Bridge Random Access Memory of InWZnO Thin Film

Abstract

In this study, the influence of oxygen concentration in InWZnO (IWZO), which was used as the switching layer of conductive bridge random access memory, (CBRAM) is investigated. With different oxygen flow during the sputtering process, the IWZO film can be fabricated with different oxygen concentrations and different oxygen vacancy distribution. In addition, the electrical characteristics of CBRAM device with different oxygen concentration are compared and further analyzed with an atomic force microscope and X-ray photoelectron spectrum. Furthermore, a stacking structure with different bilayer switching is also systematically discussed. Compared with an interchange stacking layer and other single layer memory, the CBRAM with specific stacking sequence of bilayer oxygen-poor/-rich IWZO (IWZOx/IWZOy, x < y) exhibits more stable distribution of a resistance state and also better endurance (more than 3 × 104 cycles). Meanwhile, the memory window of IWZOx/IWZOy can even be maintained over 104 s at 85 °C. Those improvements can be attributed to the oxygen vacancy distribution in switching layers, which may create a suitable environment for the conductive filament formation or rupture. Therefore, it is believed that the specific stacking bilayer IWZO CBRAM might further pave the way for emerging memory applications.

Resistive random access memory: introduction to device mechanism, materials and application to neuromorphic computing

“…The formation of conductive channels is due to dissolved metal cations migration into the insulator region from the interface of the electrochemically active electrode. In the SET operation, the metallic ions from the active electrode diffuse into the insulator and get reduced on reaching the inert electrode, thus forming a CF [ 71 ]. In the RESET operation, the metallic atoms in the CF get oxidized, thus rupturing the CF and obstructing the flow of current.…”

Effect of Electrochemically Active Top Electrode Materials on Nanoionic Conductive Bridge Y2O3 Random-Access Memory

“…In the case of CBRAM, to form the conductive metal filament, active metal top electrodes (TEs), such as Cu, are used. This is more advantageous for integrated circuits in the CMOS industry because it suppresses the electron migration or resistor-capacitor (RC) delay compared to OxRRAM [ 22 , 23 ]. In the case of CBRAM, electrodes exhibiting electrochemical activity, such as Ag or Cu, and those that are electrochemically inert, such as Au or Pt, are utilized.…”