Nanoscale 3D Stackable Ag-Doped HfO x-Based Selector Devices Fabricated through Low-Temperature Hydrogen Annealing

Ju Hyun Park, Donghyun Kim, Dae Yun Kang, Dong Su Jeon, Tae Geun Kim

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Electrochemical metallization-based threshold switching devices with active metal electrodes have been studied as a selector for high-density resistive random access memory (RRAM) technology in crossbar array architectures. However, these devices are not suitable for integration with three-dimensional (3D) crossbar RRAM arrays due to the difficulty in vertical stacking and/or scaling into the nanometer regime as well as the asymmetric threshold switching behavior and large variation in the operating voltage. Here, we demonstrate bidirectional symmetric threshold switching behaviors from a simple Pt/Ag-doped HfOx/Pt structure. While fabricating the Pt/Ag-doped HfOx/Pt film using a 250 nm hole structure, filaments composed of Ag nanoclusters were constructed through a low-temperature (∼200 °C) hydrogen annealing process where the shape of the film in a nanoscale via a hole structure was maintained for integration with 3D stackable crossbar RRAM arrays. Finite Ag filament paths in the HfOx layer led to uniform device-to-device performances. Moreover, we observed that the hydrogen annealing process reduced the delay time through the reduction of the oxygen vacancies in the HfOx layer. Consequently, the proposed Pt/Ag-doped HfOx/Pt-based nanoscale selector devices exhibited excellent performance of high selectivity (∼105), ultralow OFF current (∼10 pA), steep turn-on slope (∼2 mV/decade), and short delay time (3 μs).

Original languageEnglish
Pages (from-to)29408-29415
Number of pages8
JournalACS Applied Materials and Interfaces
Issue number32
Publication statusPublished - 2019 Aug 14


  • crossbar array
  • nonvolatile memory
  • resistive switching
  • selector device
  • threshold switching

ASJC Scopus subject areas

  • Materials Science(all)


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