Dresden 2017 – scientific programme

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DS: Fachverband Dünne Schichten

DS 36: Postersession I

DS 36.33: Poster

Wednesday, March 22, 2017, 17:00–19:00, P2-EG

Microstructure of pulsed-laser deposited Ge-Sb-Te phase-change thin films on surface-reconstructed silicon substrates — •Ulrich Roß, Andriy Lotnyk, Isom Hilmi, and Bernd Rauschenbach — Leibniz Institut für Oberflächenmodifizierung e.V. Permoserstr. 15 D-04318 Leipzig

The stable layered phases of Ge-Sb-Te based phase-change thin films are of technological interest for a number of novel properties, most prominently the crystalline resistance switching behaviour in stacked superlayers. In order to provide such thin films for structure and property investigations, precise control and understanding of the crystalline thin film growth behaviour is required.

Thin films of the prototypical phase-change material Ge₂-Sb₂-Te₅ were grown by pulsed laser deposition onto (111) oriented silicon substrates. The Si(111) 7x7 surface reconstruction was achieved by thermal treatment before natural cooldown to the final deposition temperature. The growth process was observed by in-situ RHEED measurements, and the resulting crystalline quality evaluated by SEM and XRD. Cross-sectional specimens were investigated by aberration-corrected STEM using analytic techniques as well as atomic-resolution imaging and image simulation. The results reveal a highly characteristic surface-passivated Van-der-Waals interface structure for the epitaxial growth regime, while the crystalline lattice structure is dominated by stoichiometric stacking disorder. At intermediate deposition temperatures, the domain-epitaxy growth results in stressed in-plane rotation domains and twin formation.