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In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge(2)Sb(2)Te(5)

The reliability of Ge–Sb–Te phase-change memory (PCM) devices has been limited by failure due to void formation and this still remains one of the critical issues affecting their use in storage-class memory applications. To directly observe the void formation processes in real-time, we implemented in...

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Autores principales: Oh, Sang Ho, Baek, Kyungjoon, Son, Sung Kyu, Song, Kyung, Oh, Jang Won, Jeon, Seung-Joon, Kim, Won, Yoo, Jong Hee, Lee, Kee Jeung
Formato: Online Artículo Texto
Lenguaje:English
Publicado: RSC 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9418481/
https://www.ncbi.nlm.nih.gov/pubmed/36132805
http://dx.doi.org/10.1039/d0na00223b
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author Oh, Sang Ho
Baek, Kyungjoon
Son, Sung Kyu
Song, Kyung
Oh, Jang Won
Jeon, Seung-Joon
Kim, Won
Yoo, Jong Hee
Lee, Kee Jeung
author_facet Oh, Sang Ho
Baek, Kyungjoon
Son, Sung Kyu
Song, Kyung
Oh, Jang Won
Jeon, Seung-Joon
Kim, Won
Yoo, Jong Hee
Lee, Kee Jeung
author_sort Oh, Sang Ho
collection PubMed
description The reliability of Ge–Sb–Te phase-change memory (PCM) devices has been limited by failure due to void formation and this still remains one of the critical issues affecting their use in storage-class memory applications. To directly observe the void formation processes in real-time, we implemented in situ switching of PCM devices by applying set and reset voltage pulses to a Ge(2)Sb(2)Te(5) (GST) cell inside a transmission electron microscope (TEM). The in situ TEM observations directly show that a void nucleates preferentially near the TiN bottom electrode in the GST cell, where the temperature is the highest. The nucleated void grows gradually until it reaches a certain size while migrating slowly toward the positively biased electrode. The fully grown void then continues migrating toward the positively biased electrode in subsequent set pulses. The observed polarity-dependent void migration can be explained by the field-induced redistribution of the constituent elements, especially by the electromigration of under-coordinated Te(−) ions which have vacancies around them. When the reset pulse with the same voltage polarity is applied, the voids exhibit a slight volume shrinkage but are not completely eliminated, resulting in a reset-stuck failure. The present in situ TEM observations revealing the nucleation, growth, and polarity-dependent migration of voids will contribute to the fundamental understanding of the failure by void formation in nanoscale GST-based PCM devices and help improving the design of reliable PCM devices.
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spelling pubmed-94184812022-09-20 In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge(2)Sb(2)Te(5) Oh, Sang Ho Baek, Kyungjoon Son, Sung Kyu Song, Kyung Oh, Jang Won Jeon, Seung-Joon Kim, Won Yoo, Jong Hee Lee, Kee Jeung Nanoscale Adv Chemistry The reliability of Ge–Sb–Te phase-change memory (PCM) devices has been limited by failure due to void formation and this still remains one of the critical issues affecting their use in storage-class memory applications. To directly observe the void formation processes in real-time, we implemented in situ switching of PCM devices by applying set and reset voltage pulses to a Ge(2)Sb(2)Te(5) (GST) cell inside a transmission electron microscope (TEM). The in situ TEM observations directly show that a void nucleates preferentially near the TiN bottom electrode in the GST cell, where the temperature is the highest. The nucleated void grows gradually until it reaches a certain size while migrating slowly toward the positively biased electrode. The fully grown void then continues migrating toward the positively biased electrode in subsequent set pulses. The observed polarity-dependent void migration can be explained by the field-induced redistribution of the constituent elements, especially by the electromigration of under-coordinated Te(−) ions which have vacancies around them. When the reset pulse with the same voltage polarity is applied, the voids exhibit a slight volume shrinkage but are not completely eliminated, resulting in a reset-stuck failure. The present in situ TEM observations revealing the nucleation, growth, and polarity-dependent migration of voids will contribute to the fundamental understanding of the failure by void formation in nanoscale GST-based PCM devices and help improving the design of reliable PCM devices. RSC 2020-05-14 /pmc/articles/PMC9418481/ /pubmed/36132805 http://dx.doi.org/10.1039/d0na00223b Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/
spellingShingle Chemistry
Oh, Sang Ho
Baek, Kyungjoon
Son, Sung Kyu
Song, Kyung
Oh, Jang Won
Jeon, Seung-Joon
Kim, Won
Yoo, Jong Hee
Lee, Kee Jeung
In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge(2)Sb(2)Te(5)
title In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge(2)Sb(2)Te(5)
title_full In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge(2)Sb(2)Te(5)
title_fullStr In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge(2)Sb(2)Te(5)
title_full_unstemmed In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge(2)Sb(2)Te(5)
title_short In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge(2)Sb(2)Te(5)
title_sort in situ tem observation of void formation and migration in phase change memory devices with confined nanoscale ge(2)sb(2)te(5)
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9418481/
https://www.ncbi.nlm.nih.gov/pubmed/36132805
http://dx.doi.org/10.1039/d0na00223b
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