Toward ultimate nonvolatile resistive memories: The mechanism behind ovonic threshold switching revealed

• Published in: Science advances Vol. 6; no. 9; p. eaay2830
• Main Authors: Noé, Pierre, Verdy, Anthonin, d'Acapito, Francesco, Dory, Jean-Baptiste, Bernard, Mathieu, Navarro, Gabriele, Jager, Jean-Baptiste, Gaudin, Jérôme, Raty, Jean-Yves
• Format: Journal Article Web Resource
• Language: English
• Published: United States American Association for the Advancement of Science (AAAS) 28-02-2020; American Association for the Advancement of Science
• Subjects: ab initio molecular dynamics; EXAFS; Glass; Materials Science; Ovonic Threshold Switching; Phase change; Physical, chemical, mathematical & earth Sciences; Physics; Physique; Physique, chimie, mathématiques & sciences de la terre; SciAdv r-articles; TRANSITION; NITROGEN; SHORT-RANGE ORDER; SE THIN-FILMS; GLASSES; SB
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aay2830

Fifty years after its discovery, the ovonic threshold switching (OTS) phenomenon, a unique nonlinear conductivity behavior observed in some chalcogenide glasses, has been recently the source of a real technological breakthrough in the field of data storage memories. This breakthrough was achieved because of the successful 3D integration of so-called OTS selector devices with innovative phase-change memories, both based on chalcogenide materials. This paves the way for storage class memories as well as neuromorphic circuits. We elucidate the mechanism behind OTS switching by new state-of-the-art materials using electrical, optical, and x-ray absorption experiments, as well as ab initio molecular dynamics simulations. The model explaining the switching mechanism occurring in amorphous OTS materials under electric field involves the metastable formation of newly introduced metavalent bonds. This model opens the way for design of improved OTS materials and for future types of applications such as brain-inspired computing.