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Acceleration of Crystallization Kinetics in Ge-Sb-Te-Based Phase-Change Materials by Substitution of Ge by Sn |
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| Authors: | Peter Zalden Christine Koch Melf Paulsen Marco Esters David C Johnson Matthias Wuttig Aaron M Lindenberg Wolfgang Bensch |
| Affiliation: | 1. European XFEL, Holzkoppel 4, Schenefeld, 22869 Germany;2. Institute of Inorganic Chemistry, University of Kiel, Max-Eyth-Strasse 2, Kiel, 24118 Germany;3. Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR, 97403 USA
Center for Autonomous Materials Design, Duke University, Durham, NC, 27708 USA;4. Department of Chemistry and Materials Science Institute, University of Oregon, Eugene, OR, 97403 USA;5. Institute of Physics, RWTH Aachen University, Sommerfeldstrasse 16, Aachen, 52074 Germany;6. Stanford Institute for Materials and Energy Sciences, PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 USA Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305 USA |
| Abstract: | Thin films of (Ge1–xSnx)8Sb2Te11 are prepared to study the impact of Sn-substitution on properties relevant for application in phase-change memory, a next-generation electronic data storage technology. It is expected that substitution decreases the crystallization temperature, but it is not known how the maximum crystallization rate is affected. Ge8Sb2Te11 is chosen from the (GeTe)y(Sb2Te3)1–y system of phase-change materials as a starting point due to its higher crystallization temperature as compared to the common material Ge2Sb2Te5. In situ X-ray diffraction at 5 K min?1 heating rate is performed to determine the crystallization temperature and the resulting structure. To measure the maximum crystallization rate, femtosecond optical pulses that heat the material repetitively and monitor the resulting increase of optical reflectance are used. Glasses over the entire composition range are prepared using a melt-quenching process. While at x = 0, 97, subsequent pulses are required for crystallization, one single pulse is enough to achieve the same effect at x = 0.5. The samples are further characterized by optical ellipsometry and calorimetry. The combined electrical and optical contrast and the ability to cycle between states with single femtosecond pulses renders Ge4Sn4Sb2Te11 promising for photonics applications. |
| Keywords: | crystallization kinetics data storage electro-optical materials glass formation ultrafast laser processing |