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High Resolution Imaging of Chalcogenide Superlattices for Data Storage Applications: Progress and Prospects
Author(s) -
Kooi Bart J.,
Momand Jamo
Publication year - 2019
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201800562
Subject(s) - chalcogenide , superlattice , phase change memory , nanotechnology , materials science , amorphous solid , field (mathematics) , engineering physics , computer science , optoelectronics , physics , chemistry , crystallography , mathematics , layer (electronics) , pure mathematics
Phase‐change materials (PCMs) based on Ge–Sb–Te alloys are a strong contender for next‐generation memory technology. Recently, PCMs in the form of GeTe–Sb 2 Te 3 superlattices (CSLs) have shown superior performance compared to ordinary PCM memory, which relies on switching between amorphous and crystalline phases. Although detailed atomic structure switching models have been developed with the help of ab‐initio simulations, there is still fierce scientific debate concerning the experimental verification of the actual crystal structures pertaining to the two CSL memory states. One of the strongest techniques to provide this information is (scanning) transmission electron microscopy ((S)TEM). The present article reviews the analyses of CSLs using TEM‐based techniques published during the last seven years since the seminal 2011 Nature Nanotechnology paper of Simpson et al., showing the superior performance of the CSL memory. It is critically reviewed what relevant information can be extracted from the (S)TEM results, also showing the impressive progress that has been achieved in a relatively short time frame. Finally, an outlook is given including several open questions. Although debate on actual switching mechanism in CSL memory is clearly not settled, still there is consensus in this field that CSL research has a bright future.