Dresden 2014 – scientific programme

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DS: Fachverband Dünne Schichten

DS 39: Focus Session: Resistive Switching by Redox and Phase Change Phenomena VI (Kinetics and Transport in PC materials)

DS 39.2: Talk

Thursday, April 3, 2014, 10:00–10:15, CHE 89

Growth of GeTe/Sb₂Te₃ Superlattices by Molecular Beam Epitaxy — •Rui Ning Wang¹, Jos Boschker¹, Raffaella Calarco¹, Jamo Momand², and Bart Kooi² — ¹Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany — ²Zernike Institute for Advanced Materials, Groningen, Netherlands

For their ability to be reversibly switched between a crystalline and a stable amorphous phase, drastically changing their optical and electrical properties, GeTe and GeSbTe alloys (GST) have already been used in optical data storage applications for more than a decade. These materials are also serious candidates in electrical data storage devices because of non-volatility and high scalability. Simpson et al. have demonstrated that arranging GeTe and Sb₂Te₃ into a superlattice (SL) structure enables an analogous crystalline ↔ crystalline switching mechanism that greatly reduces the switching energy while improving the cyclability and switching speed [1].

In the work presented here, GeTe/Sb₂Te₃ SLs were grown on Si(111) substrates by molecular beam epitaxy. The epi-structures showed an out-of-plane Si ⟨111⟩ ∥ SL ⟨0001⟩ orientation and in-plane Si ⟨112⟩ ∥ SL ⟨1010⟩ orientation. An effort has been made to reduce the layer thickness of each constituent down to 1 nm for GeTe and to 2 nm for Sb₂Te₃, and improve surface and interface roughness. These state of the art superlattices provide a clear platform for fundamental studies of the switching mechanism in such structures.

[1] R. Simpson et al., Nature nanotechnology, vol. 6, pp. 501-5, 2011.