Structural transformations in Ge2Sb2Te5 under high pressure and temperature

Year: 2015

Authors: Mio A. M., Privitera S., D’Arrigo, G., Ceppatelli M., Gorelli F., Santoro M., Miritello M., Bini R., Rimini E.

Autors Affiliation: CNR, IMM, I-95121 Catania, Italy; CNR, ICCOM, I-50019 Sesto Fiorentino, FI, Italy; LENS European Lab Nonlinear Spect, I-50019 Sesto Fiorentino, FI, Italy; CNR, INO, I-50019 Sesto Fiorentino, FI, Italy; CNR, IMM, MATIS, I-95123 Catania, Italy; Univ Florence, I-50019 Sesto Fiorentino, FI, Italy.

Abstract: The structural transformations occurring in Ge2Sb2Te5 films heated at temperature up to 400 degrees 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 degrees C at 8 GPa and to 230 degrees 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. (C) 2015 AIP Publishing LLC.

Journal/Review: JOURNAL OF APPLIED PHYSICS

Volume: 118 (6)      Pages from: 64503-1  to: 64503-5

KeyWords: Ge2Sb2Te5
DOI: 10.1063/1.4928561

Citations: 5
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