GeSe ovonic threshold switch: the impact of functional layer thickness and device size

Abstract Three-dimensional phase change memory (3D PCM), possessing fast-speed, high-density and nonvolatility, has been successfully commercialized as storage class memory. A complete PCM device is composed of a memory cell and an associated ovonic threshold switch (OTS) device, which effectively r...

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Main Authors: Jiayi Zhao, Zihao Zhao, Zhitang Song, Min Zhu
Format: Article
Language:English
Published: Nature Portfolio 2024-03-01
Series:Scientific Reports
Subjects:
Online Access:https://doi.org/10.1038/s41598-024-57029-7
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author Jiayi Zhao
Zihao Zhao
Zhitang Song
Min Zhu
author_facet Jiayi Zhao
Zihao Zhao
Zhitang Song
Min Zhu
author_sort Jiayi Zhao
collection DOAJ
description Abstract Three-dimensional phase change memory (3D PCM), possessing fast-speed, high-density and nonvolatility, has been successfully commercialized as storage class memory. A complete PCM device is composed of a memory cell and an associated ovonic threshold switch (OTS) device, which effectively resolves the leakage current issue in the crossbar array. The OTS materials are chalcogenide glasses consisting of chalcogens such as Te, Se and S as central elements, represented by GeTe6, GeSe and GeS. Among them, GeSe-based OTS materials are widely utilized in commercial 3D PCM, their scalability, however, has not been thoroughly investigated. Here, we explore the miniaturization of GeSe OTS selector, including functional layer thickness scalability and device size scalability. The threshold switching voltage of the GeSe OTS device almost lineally decreases with the thinning of the thickness, whereas it hardly changes with the device size. This indicates that the threshold switching behavior is triggered by the electric field, and the threshold switching field of the GeSe OTS selector is approximately 105 V/μm, regardless of the change in film thickness or device size. Systematically analyzing the threshold switching field of Ge–S and Ge–Te OTSs, we find that the threshold switching field of the OTS device is larger than 75 V/μm, significantly higher than PCM devices (8.1–56 V/μm), such as traditional Ge2Sb2Te5, Ag–In–Sb–Te, etc. Moreover, the required electric field is highly correlated with the optical bandgap. Our findings not only serve to optimize GeSe-based OTS device, but also may pave the approach for exploring OTS materials in chalcogenide alloys.
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spelling doaj.art-e12817f96b644be8a8e9cdf24f432b3c2024-03-24T12:20:11ZengNature PortfolioScientific Reports2045-23222024-03-011411910.1038/s41598-024-57029-7GeSe ovonic threshold switch: the impact of functional layer thickness and device sizeJiayi Zhao0Zihao Zhao1Zhitang Song2Min Zhu3State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, Chinese Academy of SciencesState Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, Chinese Academy of SciencesState Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, Chinese Academy of SciencesState Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-System and Information Technology, Chinese Academy of SciencesAbstract Three-dimensional phase change memory (3D PCM), possessing fast-speed, high-density and nonvolatility, has been successfully commercialized as storage class memory. A complete PCM device is composed of a memory cell and an associated ovonic threshold switch (OTS) device, which effectively resolves the leakage current issue in the crossbar array. The OTS materials are chalcogenide glasses consisting of chalcogens such as Te, Se and S as central elements, represented by GeTe6, GeSe and GeS. Among them, GeSe-based OTS materials are widely utilized in commercial 3D PCM, their scalability, however, has not been thoroughly investigated. Here, we explore the miniaturization of GeSe OTS selector, including functional layer thickness scalability and device size scalability. The threshold switching voltage of the GeSe OTS device almost lineally decreases with the thinning of the thickness, whereas it hardly changes with the device size. This indicates that the threshold switching behavior is triggered by the electric field, and the threshold switching field of the GeSe OTS selector is approximately 105 V/μm, regardless of the change in film thickness or device size. Systematically analyzing the threshold switching field of Ge–S and Ge–Te OTSs, we find that the threshold switching field of the OTS device is larger than 75 V/μm, significantly higher than PCM devices (8.1–56 V/μm), such as traditional Ge2Sb2Te5, Ag–In–Sb–Te, etc. Moreover, the required electric field is highly correlated with the optical bandgap. Our findings not only serve to optimize GeSe-based OTS device, but also may pave the approach for exploring OTS materials in chalcogenide alloys.https://doi.org/10.1038/s41598-024-57029-7Ovonic threshold switchGeSeScalabilitySelectorThreshold switching fieldPhase change memory
spellingShingle Jiayi Zhao
Zihao Zhao
Zhitang Song
Min Zhu
GeSe ovonic threshold switch: the impact of functional layer thickness and device size
Scientific Reports
Ovonic threshold switch
GeSe
Scalability
Selector
Threshold switching field
Phase change memory
title GeSe ovonic threshold switch: the impact of functional layer thickness and device size
title_full GeSe ovonic threshold switch: the impact of functional layer thickness and device size
title_fullStr GeSe ovonic threshold switch: the impact of functional layer thickness and device size
title_full_unstemmed GeSe ovonic threshold switch: the impact of functional layer thickness and device size
title_short GeSe ovonic threshold switch: the impact of functional layer thickness and device size
title_sort gese ovonic threshold switch the impact of functional layer thickness and device size
topic Ovonic threshold switch
GeSe
Scalability
Selector
Threshold switching field
Phase change memory
url https://doi.org/10.1038/s41598-024-57029-7
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AT zihaozhao geseovonicthresholdswitchtheimpactoffunctionallayerthicknessanddevicesize
AT zhitangsong geseovonicthresholdswitchtheimpactoffunctionallayerthicknessanddevicesize
AT minzhu geseovonicthresholdswitchtheimpactoffunctionallayerthicknessanddevicesize