Phase-field modeling of the non-congruent crystallization of a ternary Ge–Sb–Te alloy for phase-change memory applications

The ternary alloy of germanium, antimony, and tellurium (GST) is widely used as a material for phase-change memories. In particular, the stoichiometric compound Ge 2Sb 2Te 5 exhibits a rapid congruent crystallization. To increase the temperature at which spontaneous crystallization erases the stored...

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Bibliographic Details
Published in:Journal of applied physics 2020-11, Vol.128 (18)
Main Authors: Bayle, R., Cueto, O., Blonkowski, S., Philippe, T., Henry, H., Plapp, M.
Format: Article
Language:English
Subjects:
Alloys
Amorphous materials
Antimony
Applied physics
Computer memory
Condensed Matter
Crystallization
Engineering Sciences
Germanium
Germanium base alloys
Grain structure
Materials
Nucleation
Physics
Recrystallization
Tellurium
Ternary alloys
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Summary:The ternary alloy of germanium, antimony, and tellurium (GST) is widely used as a material for phase-change memories. In particular, the stoichiometric compound Ge 2Sb 2Te 5 exhibits a rapid congruent crystallization. To increase the temperature at which spontaneous crystallization erases the stored information, alloys that are enriched in germanium have been investigated. Their crystallization is accompanied by segregation and eventually the nucleation of a new, germanium-rich phase. In order to model the redistribution of alloy components and the time evolution of the microstructure during device operations, we develop a multi-phase-field model for the crystallization of GST that includes segregation and couple it with orientation fields that describe the grain structure. We demonstrate that this model is capable to capture both the emergence of a two-phase polycrystalline structure starting from an initially amorphous material, and the melting and recrystallization during the SET and RESET operations in a memory cell of the “wall” type.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0023692