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DS: Fachverband Dünne Schichten

DS 34: Focus Session: Resistive Switching by Redox and Phase Change Phenomena V (Structure, growth and general properties of PC materials)

DS 34.3: Talk

Wednesday, April 2, 2014, 19:15–19:30, CHE 89

Atomic resolution investigation of defect structures in textured metastable Ge₂Sb₂Te₅ by aberration corrected high resolution STEM — •Ulrich Roß, Andriy Lotnyk, Erik Thelander, and Bernd Rauschenbach — Leibniz-Institut für Oberflächenmodifizierung e.V. Permoserstr. 15 D-04318 Leipzig

Local features in the structure of phase change materials (PCM) are of foremost importance for the characteristic phase transformation mechanics made use of in data storage applications. Specifically, distribution of vacancies as well as stabilization of an ordered sublattice in the amorphous and metastable phase are believed to significantly influence the performance of PCM-based devices. However, very few studies have been able to resolve the local nanostructure in an experimental setting.

We have employed a state of the art FEI Titan³ G2 60-300kV probe aberration corrected transmission electron microscope in order to investigate the atomic structure of pulsed laser deposited metastable Ge₂Sb₂Te₅ (GST) with sub-angstrom resolution. Quantitative image simulations were carried out in order to evaluate local chemical information. The results of the investigation are discussed in the context of past and current structure models of metastable GST, and a brief outlook on the possibility of in-situ heating atomic resolution imaging experiments is given.