Super Nonlinear Electrodeposition–Diffusion-Controlled Thin-Film Selector

Abstract

Selector elements with high nonlinearity are an indispensable part in constructing high density, large-scale, 3D stackable emerging nonvolatile memory and neuromorphic network. Although significant efforts have been devoted to developing novel thin-film selectors, it remains a great challenge in achieving good switching performance in the selectors to satisfy the stringent electrical criteria of diverse memory elements. In this work, we utilized high-defect-density chalcogenide glass (GeSbTe) in conjunction with high mobility Ag element (Ag-GST) to achieve a super nonlinear selective switching. A novel electrodeposition-diffusion dynamic selector based on Ag-GST exhibits superior selecting performance including excellent nonlinearity (<5 mV/dev), ultra-low leakage (<10 fA), and bidirectional operation. With the solid microstructure evidence and dynamic analyses, we attributed the selective switching to the competition between the electrodeposition and diffusion of Ag atoms in the glassy GST matrix under electric field. A switching model is proposed, and the in-depth understanding of the selective switching mechanism offers an insight of switching dynamics for the electrodeposition-diffusion-controlled thin-film selector. This work opens a new direction of selector designs by combining high mobility elements and high-defect-density chalcogenide glasses, which can be extended to other materials with similar properties.

Design of a Controllable Redox‐Diffusive Threshold Switching Memristor

“…These applications are mainly based on the crossbar array integration, where sneak path current issues notoriously obstruct the normal read-and-write operations. Sneak path currents originate from neighboring cells around a target cell, and thus resulting in unexpected misoperation www.advelectronicmat.de Au/Ag nanowires-PDMS composite/ Au [75] Bidirectional 3 mA 10 10 ≈0.4 V <4 mV dec −1 520 ns 110 µs >10 6 Nanowire composite Selectors Pt/Ag-Ge 2 Sb 2 Te 5 / TiW [100] Bidirectional 100 µA…”

A Study on the Interfacial Structure Design of Self‐Compliance Ni/HfOx/Ni Bipolar Selectors and Trap‐to‐Trap Tunneling Mechanism Caused by Redox Reaction

“…The operation mechanism of selectors, especially those with inert metal electrodes, remains unclear, due to their volatility . Lin et al proposed a V/HfO 2 /TiN device to exhibit both resistive switching characteristics as RRAM and selector characteristics by introducing vanadium to the top electrode (TE) .…”

“…They illustrated that the space charge limit current mechanism was found at the low resistance state (LRS) during selector operation, and Poole–Frenkel emission conduction was recognized at the high resistance state (HRS). The mechanism of the selective switching behavior of heavily doped Ag–Ge 2 Sb 2 Te 5 material can be attributed to the rapid electrodeposition and diffusion dynamics of Ag in the glassy Ge 2 Sb 2 Te 5 material . However, the mechanism is only applicable to those exceptional materials.…”

“…The operation mechanism of selectors, especially those with inert metal electrodes, remains unclear, due to their volatility. [11,[18][19][20] Lin et al proposed a V/HfO 2 /TiN device to exhibit both resistive switching characteristics as RRAM and selector characteristics by introducing vanadium to the top electrode (TE). [18] They illustrated that the space charge limit current mechanism was found at the low resistance state (LRS) during selector operation, and Poole-Frenkel emission conduction was recognized at the high resistance state (HRS).…”

“…The mechanism of the selective switching behavior of heavily doped Ag-Ge 2 Sb 2 Te 5 material can be attributed to the rapid electrodeposition and diffusion dynamics of Ag in the glassy Ge 2 Sb 2 Te 5 material. [19] However, the mechanism is only applicable to those exceptional materials. A more detailed experimental study of the selector mechanism is still in its infancy.…”