Structural transformations in Ge{sub 2}Sb{sub 2}Te{sub 5} under high pressure and temperature

Journal Article · Fri Aug 14 00:00:00 EDT 2015 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4928561· OSTI ID:22494732

Mio, A. M.; D'Arrigo, G.; Rimini, E. ^[1]; Ceppatelli, M. ^[2]; Gorelli, F.; Santoro, M. ^[3]; Miritello, M. ^[4]; Bini, R. ^[3]

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1. IMM-CNR, Istituto per la Microelettronica e Microsistemi, Consiglio Nazionale delle Ricerche, Strada VIII 5, Zona Industriale, I-95121 Catania (Italy)
2. ICCOM-CNR, Istituto di Chimica dei Composti OrganoMetallici, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy)
3. LENS, European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, I-50019 Sesto Fiorentino (Italy)
4. MATIS-IMM-CNR, via S. Sofia 64, I-95123 Catania (Italy)

The structural transformations occurring in Ge{sub 2}Sb{sub 2}Te{sub 5} films heated at temperature up to 400 °C, and under hydrostatic pressure up to 12 GPa, have been investigated through in-situ X ray diffraction measurements. The adopted experimental conditions are close to those experienced by the phase change material during the SET (crystallization)/RESET (amorphization) processes in a nonvolatile memory device. The compression enhances the thermal stability of the amorphous phase, which remains stable up to 180 °C at 8 GPa and to 230 °C at 12 GPa. The structure of the crystalline phases is also modified, with the formation of a CsCl-type structure instead of rock-salt and of a GeS-type structure at the temperature at which usually the trigonal stable phase is formed. Overall, the stability of the stable phase appears to be more affected by the compression. We argue that the presence of weak bonds associated to the van der Waals gaps is a determining factor for the observed reduced stability.

• OSTI ID: 22494732
• Journal Information: Journal of Applied Physics, Vol. 118, Issue 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMORPHOUS STATE
CESIUM CHLORIDES
CRYSTALLIZATION
GERMANIUM COMPOUNDS
GERMANIUM SULFIDES
MEMORY DEVICES
PHASE CHANGE MATERIALS
PRESSURE RANGE GIGA PA
STABILITY
TEMPERATURE RANGE 0400-1000 K
THIN FILMS
TRANSFORMATIONS
VAN DER WAALS FORCES
X-RAY DIFFRACTION