Ovonic threshold switching in polycrystalline zinc telluride thin films deposited by RF sputtering

Taeho Kim, Youngjae Kim, Ingwan Lee, Dayoon Lee, Hyunchul Sohn

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Chalcogenide materials of the amorphous phase with low band gaps were reported to show Ovonic threshold switching (OTS), making them suitable for selection devices in cross-point memory arrays. Herein, we report that ZnTe films with polycrystalline structures show OTS behavior. Nearly stoichiometric ZnTe thin films were deposited by an RF sputtering method. X-ray diffraction analysis indicated that the films were polycrystalline. The optical band gaps of the ZnTe films were estimated as 2.2 eV from UV-visible spectroscopy transmittance measurements. Photoluminescence measurements indicated the existence of deep-level defects in the ZnTe thin films. Although these ZnTe films have a polycrystalline structure with a relatively high band gap, I-V profiles show OTS characteristics, with a selectivity of over 104, fast threshold switching time in the sub-10 ns scale, and thermal stability up to 400 °C. ZnTe also shows switching endurance for more than 109 cycles without Vth drift, maintaining its selectivity of 104. Thus, we improved the threshold switching characteristics by using a wide band-gap and polycrystalline-structured ZnTe-based chalcogenide material. Post-annealing experiments indicated that the thermal budget of the ZnTe thin film was sufficient for stacked cross-point array structures, thereby overcoming a previous limitation of chalcogenide switching materials. This material is promising for application in high-density cross-point memory arrays as the selection device.

Original languageEnglish
Article number13LT01
Issue number13
Publication statusPublished - 2019 Feb 5

Bibliographical note

Funding Information:
This work was supported by the Ministry of Trade, Industry & Energy (MoTIE, Korea) under the Industrial Strategic Technology Development Program (Grant no. 10068075) and the Brain Korea 21 plus projects (BK21 plus).

Publisher Copyright:
© 2019 IOP Publishing Ltd.

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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