Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-05T04:17:50.216Z Has data issue: false hasContentIssue false
  • English
  • Français

Thermal and elastic properties of Ge-Sb-Te based phase-change materials

Published online by Cambridge University Press:  08 July 2011

P. Zalden ,
C. Bichara ,
J. v. Eijk ,
R. P. Hermann ,
I. Sergueev ,
G. Bruns ,
S. Buller ,
W. Bensch ,
T. Matsunaga  and
N. Yamada
...Show all authors
P. Zalden
Affiliation:
I. Physikalisches Institut (IA), RWTH Aachen University, Aachen, Germany JARA-FIT, RWTH Aachen, 52056 Aachen, Germany
C. Bichara
Affiliation:
Centre Interdisciplinaire de Nanoscience de Marseille, CINaM – CNRS and Aix-Marseille University, Campus de Luminy, 13288 - Marseille - Cedex 9 - France
J. v. Eijk
Affiliation:
I. Physikalisches Institut (IA), RWTH Aachen University, Aachen, Germany JARA-FIT, RWTH Aachen, 52056 Aachen, Germany
R. P. Hermann
Affiliation:
Jülich Centre for Neutron Science JCNS and Peter Grünberg Institut PGI, JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany Faculté des Sciences, Université de Liège, 4000 Liège, Belgium
I. Sergueev
Affiliation:
I. Physikalisches Institut (IA), RWTH Aachen University, Aachen, Germany
G. Bruns
Affiliation:
I. Physikalisches Institut (IA), RWTH Aachen University, Aachen, Germany JARA-FIT, RWTH Aachen, 52056 Aachen, Germany
S. Buller
Affiliation:
Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
W. Bensch
Affiliation:
Institut für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
T. Matsunaga
Affiliation:
Materials Science and Analysis Technology Centre, Panasonic Corporation, 3-1-1 Yagumo-Nakamachi, Moriguchi, Osaka 570-8501, Japan Japan Synchrotron Radiation Research Institute, Hyogo, Japan
N. Yamada
Affiliation:
Japan Synchrotron Radiation Research Institute, Hyogo, Japan Digital & Network Technology Development Centre, Panasonic Corporation, Osaka, Japan
M. Wuttig
Affiliation:
I. Physikalisches Institut (IA), RWTH Aachen University, Aachen, Germany JARA-FIT, RWTH Aachen, 52056 Aachen, Germany
Get access

Abstract

Phase-change materials undergo a change in bonding mechanism upon crystallization, which leads to pronounced modifications of the optical properties and is accompanied by an increase in average bond lengths as seen by extended x-ray absorption fine structure (EXAFS), neutron and x-ray diffraction. The reversible transition between a crystalline and an amorphous phase and its related property contrast are already employed in non-volatile data storage devices, such as rewritable optical discs and electronic memories. The crystalline phase of the prototypical material GeSb2Te4 is characterized by resonant bonding and pronounced disorder, which help to understand their optical and electrical properties, respectively. A change in bonding, however, should also affect the thermal properties, which will be addressed in this study. Based on EXAFS data analyses it will be shown that the thermal and static atomic displacements are larger in the meta-stable crystalline state. This indicates that the bonds become softer in the crystalline phase. At the same time, the bulk modulus increases upon crystallization. These observations are confirmed by the measured densities of phonon states (DPS), which reveal a vibrational softening of the optical modes upon crystallization. This demonstrates that the change of bonding upon crystallization in phase-change materials also has a profound impact on the lattice dynamics and the resulting thermal properties.

Keywords

thermal conductivitystructuralextended x-ray absorption fine structure(EXAFS)
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1338: Symposium R – Phase-Change Materials for Memory and Reconfigurable Electronics Applications , 2011 , mrss11-1338-r06-03
Copyright
Copyright © Materials Research Society 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1] Ovshinsky, S.R., “Reversible Electrical Switching Phenomena in Disordered Structures,” Physical Review Letters, vol. 21, 1968, p. 1450.Google Scholar
[2] Yamada, N., Ohno, E., Nishiuchi, K., Akahira, N., and Takao, M., “Rapid-phase transitions of GeTe-Sb, Te, pseudobinary for an optical disk memory,” Journal of Applied Physics, vol. 69, 1991, pp. 2849–2856.Google Scholar
[3] Wuttig, M. and Yamada, N., “Phase-change materials for rewriteable data storage,” Nature materials, vol. 6, 2007, pp. 824–832.Google Scholar
[4] Lencer, D., Salinga, M., and Wuttig, M., “Design Rules for Phase-Change Materials in Data Storage Applications,” Advanced Materials, vol. 23, May 2010, pp. 2030–2058.Google Scholar
[5] Wełnic, W., Pamungkas, A., Detemple, R., Steimer, C., Blügel, S., and Wuttig, M., “Unravelling the interplay of local structure and physical properties in phase-change materials,” Nature Materials, vol. 5, Dec. 2005, pp. 56–62.Google Scholar
[6] Kolobov, A., “Understanding the phase-change mechanism of rewritable optical media,” Nature Materials, vol. 3, 2004, pp. 703–708.Google Scholar
[7] Zallen, R., The Physics of Amorphous Solids, Wiley, 1983.Google Scholar
[8] Jóvári, P., Kaban, I., Steiner, J., Beuneu, B., Schöps, A., and Webb, M., “Local order in amorphous Ge2Sb2Te5 and GeSb2Te4 ,” Physical Review B, vol. 77, 2008, p. 035202.Google Scholar
[9] Baker, D., Paesler, M., Lucovsky, G., Agarwal, S., and Taylor, P., “Application of Bond Constraint Theory to the Switchable Optical Memory Material Ge2Sb2Te5 ,” Physical Review Letters, vol. 96, 2006, pp. 5–7.Google Scholar
[10] Matsunaga, T. and Yamada, N., “Structural investigation of GeSb2Te4: A high-speed phase-change material,” Physical Review B, vol. 69, Mar. 2004, pp. 1–8.Google Scholar
[11] Littlewood, P.B. and Heine, V., “The infrared effective charge in IV-VI compounds: I. A simple one-dimensional model,” vol. 12, 1979, p. 4431.Google Scholar
[12] Littlewood, P.B., “The infrared effective charge in IV-VI compounds: II. A three dimensional calculation,” vol. 12, 1979, p. 4441.Google Scholar
[13] Lencer, D., Salinga, M., Grabowski, B., Hickel, T., Neugebauer, J., and Wuttig, M., “A map for phase-change materials,” Nature Materials, vol. 7, 2008, p. 972–977.Google Scholar
[14] Shportko, K., Kremers, S., Woda, M., Lencer, D., Robertson, J., and Wuttig, M., “Resonant bonding in crystalline phase-change materials,” Nature Materials, vol. 7, 2008, p. 653–658.Google Scholar
[15] Huang, B. and Robertson, J., “Bonding origin of optical contrast in phase-change memory materials,” Physical Review B, vol. 81, 2010, p. 1204.Google Scholar
[16] Wuttig, M., Lüsebrink, D., Wamwangi, D., Wełnic, W., Gillessen, M., and Dronskowski, R., “The role of vacancies and local distortions in the design of new phase-change materials.,” Nature materials, vol. 6, 2007, pp. 122–8.Google Scholar
[17] Shamoto, S., Yamada, N., Matsunaga, T., Proffen, T., Richardson, J.W. Jr., Chung, J.H., and Egami, T., “Large displacement of germanium atoms in crystalline Ge2Sb2Te5 ,” Appl. Phys. Lett., vol. 86, 2005, p. 1904.Google Scholar
[18] van Eijk, J. M., Bichara, C., Zalden, P., Braun, C., Buller, S., Bensch, W., and Wuttig, M., “Differences in local order of amorphous and crystalline Ge1Sb2Te4 probed by X-Ray absorption spectroscopy,” submitted to Phys. Rev. B, 2011.Google Scholar
[19] Blachowicz, T., Beghi, M.G., Güntherodt, G., Beschoten, B., Dieker, H., and Wuttig, M., “Crystalline phases in the GeSb2Te4 alloy system: Phase transitions and elastic properties,” Journal of Applied Physics, vol. 102, 2007, p. 093519.Google Scholar
[20] These authors presented a corrected transformation of measured elastic constants from [17] to the bulk modulus: Caravati, S., Bernasconi, M., Kühne, T., Krack, M., and Parrinello, M., “Unravelling the Mechanism of Pressure Induced Amorphization of Phase Change Materials,” Physical Review Letters, vol. 102, 2009, pp. 1–4.Google Scholar
[21] Park, I., Jung, J., Ryu, S., Choi, K., Yu, B., Park, Y., Han, S., and Joo, Y., “Thermomechanical properties and mechanical stresses of Ge2Sb2Te5 films in phase-change random access memory,” Thin Solid Films, vol. 517, Nov. 2008, pp. 848–852.Google Scholar
[22] Rickers, K., Brüggmann, U., Drube, W., Herrmann, M., Heuer, J., Welter, E., Schulte-Schrepping, H., and Schulz-Ritter, H., “New XAFS Facility for In-Situ Measurements at Beamline C at HASYLAB,” AIP Conference Proceedings, vol. 879, 2007, p. 907.Google Scholar
[23] Ravel, B. and Newville, M., “ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT.,” Journal of synchrotron radiation, vol. 12, Jul. 2005, pp. 537–41.Google Scholar
[24] Ankudinov, A.L., Rehr, J.J., and Conradson, S.D., “Real-space multiple-scattering calculation and interpretation of x-ray-absorption near-edge structure,” Physical Review B, vol. 58, Sep. 1998, pp. 7565–7576.Google Scholar
[25] Wille, H.C., Hermann, R.P., Sergueev, I., Leupold, O., Linden, P.V.D., Sales, B.C., Grandjean, F., Long, G.J., Rüffer, R., and Shvydko, Y.V., “Antimony vibrations in skutterudites probed by 121Sb nuclear inelastic scattering,” Phys. Rev. B, vol. 76, 2007, p. 140301.Google Scholar
[26] Wille, H.C., Hermann, R.P., Sergueev, I., Pelzer, U., Möchel, A., Claudio, T., Rüffer, R., Said, A., and Shvydko, Y.V., “Nuclear forward and inelastic spectroscopy on 125Te and Sb2-125Te3 ,” Europhysics Letters, vol. 91, 2010, p. 62001.Google Scholar
[27] Koningsberger, D.C. and Prins, R., eds., X-Ray Absorption, John Wiley & Sons Ltd, 1988.Google Scholar
[28] Cordero, B., Gómez, V., Platero-Prats, A.E., Revés, M., Echeverría, J., Cremades, E., Barragán, F., and Alvarez, S., “Covalent radii revisited,” Dalton transactions (Cambridge, England: 2003), Jun. 2008, pp. 2832–2838.Google Scholar
[29] Gaspard, J.P., Pellegatti, A., Marinelli, F., and Bichara, C., “Peierls instabilities in covalent structures I. Electronic structure, cohesion and the Z=8-N rule,” Philosophical Magazine B, vol. 77, Mar. 1998, pp. 727–744.Google Scholar
[30] Lencer, D., “Design rules, local structure and lattice dynamics of phase change materials for data storage applications,” RWTH Aachen, 2011.Google Scholar
[31] Rüffer, R. and Chumakov, A.I., “Nuclear inelastic scattering,” Hyperfine Interactions, vol. 128, Jul. 2000, pp. 255–272.Google Scholar
[32] Matsunaga, T., Yamada, N., Kojima, R., Shamoto, S., Sato, M., Tanida, H., Uruga, T., Kohara, S., Takata, M., Zalden, P., Bruns, G., Sergueev, I., Wille, H.C., Hermann, R.P., and Wuttig, M., “Phase change materials: Vibrational softening upon crystallization and its impact on thermal properties,” Advanced Functional Materials, 2011.Google Scholar
[33] Maley, N., Beeman, D., and Lannin, J.S., “Dynamics of tetrahedral networks Amorphous Si and Ge,” Physical Review B, vol. 38, 1988, p. 10611.Google Scholar
[34] Nellin, G. and Nilsson, G., “Phonon Density of States in Germanium at 80 K Measured by Neutron Spectrometry,” Physical Review B, vol. 5, 1972, p. 3151.Google Scholar