Electrical nanocharacterization of copper tetracyanoquinodimethane layers dedicated to resistive random access memories

Abstract

The local electrical properties of copper tetracyanoquinodimethane (CuTCNQ)/HfO2/Pt stacks were investigated thanks to conductive-atomic force microscopy (AFM) measurements. Local I-V and I-t spectroscopy evidenced repeatable and reversible bipolar electrical switching (SET and RESET operations) at the nanometer scale beneath the AFM tip. Experimental results suggest that resistive switching is due to the creation/dissolution of conductive filaments bridging the CuTCNQ surface to the AFM tip. A physical model based on the migration of Cu+ ions within a nanogap and the growth of a conductive filament shows an excellent agreement with the experimental results during SET operation achieved at nanoscale.

Ge2Sb2Te5 layer used as solid electrolyte in conductive-bridge memory devices fabricated on flexible substrate

“…[25]. As already reported in a previous work [22], the water meniscus may also act as an electrolyte within which metallic ions may move toward the metallic tip to be electrochemically reduced. Therefore the total width (100 nm) of the electrodeposited protrusion results from interplay between the extension of the field lines generated underneath the AFM tip, which is in the order of the contact area [23], the complex contact between the apex of the tip and the surface roughness and the diameter of the water meniscus formed around the tip which can be, at first order, as large as 2 times the radius of curvature (r C ) of the tip (r C~2 5 nm in our experiment), depending on atmospheric conditions.…”

Resistance Switching Characteristics of Solid Electrolyte Chalcogenide Ag2Se Nanoparticles for Flexible Nonvolatile Memory Applications

“…In the specific case of electrochemical metallization cells (EMC), the memory element consists of a solid electrolyte ionic conductor between electrochemically active metallic plates such as Ag, Cu and Ni, and inert metallic plates such as Pt, Au and W. In these devices, a metal filament can be formed directly by chemical redox reactions between the solid electrolytes and the active metals. The resulting metal cations can directly and rapidly move through the fast ionic conductor matrix by drift and diffusion 13–16. This results in faster switching with lower energy consumption.…”

Resonance Raman spectroscopy studies on photoinduced AgTCNQF4 charge transfer and its electrical switching behavior

“…On the basis of CuTCNQ, the electric switching mechanism of the AgTCNQF 4 microrods is described. As shown in Scheme , an air gap or water meniscus was formed between the Au‐coated AFM tip and AgTCNQF 4 surface.…”