How does chalcogenide microstructure correlate to electrical switching dynamics?
Leifang Zhang, Christophe Gatel, and their colleagues at CEMES-CNRS, STMicroelectronics, and Université Paul Sabatier published on their use of the Hummingbird Scientific in-situ MEMS heating + biasing TEM holder to examine electrical biasing of Ge-rich Ge-Sb-Te (GST) chalcogenide thin films using in-situ transmission electron microscopy. Microstructural evolution of the phase change memory nanobridges is characterized in terms of electrical pulse modification, the electrochemical migration, local current density, void formation, and the corresponding switching mechanism.
a) Designed specimen structure and b) Final FIB specimen structure with a reduced region of interest (500 × 500 nm2) due to extra W deposition. c) Microstructural characterization of the initial stage of the specimen as well as after each pulse (A-D) including bright-field, dark-field, and selected area electron diffraction patterns. Copyright © 2024 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
The nanobridges, fabricated using focused-ion beam (FIB), were affixed bridging the leads of FIB lamella-compatible biasing microchips. Pulses of various waveforms representing SET and RESET signals were injected through the nanobridges, and TEM imaging and diffraction of microstructural evolution is collected to correspond with measured iv plots. Reversible switching dynamics such as threshold switching and Joule-heating mediated switching mechanisms are confirmed, advancing fundamental understanding of one candidate for the active material in non-volatile random-access memory (RAM), as well as the method for nanoscale characterization of phase-change materials.
Reference: Leifeng Zhang, Bumsu Park, Lucas Chapuis, Kilian Gruel, Robin Cours, Frédéric Lorut, Martin Hÿtch, Christophe Gatel, Journal of Alloys and Compounds (2024) DOI: 10.1016/j.jallcom.2024.175626
Full paper Copyright © 2024 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
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