Resistive switching characteristics and mechanism of bilayer HfO2/ZrO2 structure deposited by radio-frequency sputtering for nonvolatile memory

Muhammad Ismail, Zahida Batool, Khalid Mahmood, Anwar Manzoor Rana, Byung Do Yang, Sungjun Kim

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50 Scopus citations

Abstract

In this study, a bilayer HfO2/ZrO2 thin film structure was deposited by radio frequency sputtering at room temperature (RT) to investigate the resistive switching (RS) characteristics, mechanism as well as their reproducibility. Bilayer HfO2/ZrO2 structured device > 103 DC switching cycles at RT, and > 10 ON/OFF ratio. The RS uniformity and mechanism were evaluated by Gaussian data fitting and distributions of oxygen vacancies (VOs) in the HfO2 and ZrO2 layers through X-ray photo electron spectroscopy (XPS) analysis, respectively. Because of higher thermal conductivity (2.7Wm-1K-1) and lower Gibbs free energy (ΔGo=-1100kJ/mol) of ZrO2 layer as compared to those of HfO2 layer (1.1Wm-1K-1,ΔGo=-1010.8kJ/mol), an easier reduction and oxidation of filaments took place by exchanging oxygen ions with each other (ZrO2/HfO2). A VOs-based filamentary model has been proposed to explain RS mechanism. Furthermore, a current transport mechanism is noted be based on Schottky emission in the high field region of the high resistance states (HRS).

Original languageEnglish
Article number103275
JournalResults in Physics
Volume18
DOIs
StatePublished - Sep 2020

Keywords

  • Bilayer HfO/ZrO structure
  • Gibbs free energy
  • Resistive switching
  • Schottky emission
  • Thermal conductivity

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