Dresden 2017 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 21: Thin Film Characterisation: Structure Analysis and Composition II

DS 21.8: Vortrag

Dienstag, 21. März 2017, 11:30–11:45, CHE 91

Interfacial oxide formation during ALD oxide growth on reactive metals for resistive switching devices — •Stephan Aussen, Alexander Hardtdegen, Katharina Skaja, Regina Dittmann, and Susanne Hoffmann-Eifert — Peter Grünberg Institut (PGI-7) and JARA-FIT, Forschungszentrum Jülich, 52425 Jülich, Germany

In this study we investigate the oxidation behavior of different metals (M) including Hf, Ta and Pt during atomic layer deposition (ALD) of stoichiometric oxide films (M′O) including Al₂O₃, TiO₂ and HfO₂ and the switching behavior of the resulting stacks. The 25 nm thick dense metal films with low surface roughness < 0.3 nm were grown on thermal oxidized Si wafers in an off-axis sputter tool with a base pressure < 10⁻¹⁰ mbar. The hexagonal Hf films and the cubic Pt films show (002) and (111) textures, respectively. In contrast, the Ta films consist of a mixture of the α- and β-tantalum phase. All metal films were transferred under ultra-high vacuum into an ALD plasma system. 3 nm thick oxide layers were deposited at 300 ^∘C using O₂-plasma as the oxygen source. The resulting stacks were investigated by x-ray photoelectron spectroscopy to study the oxidation of the metal surface due to the oxide deposition. In addition, complementary resistive switching experiments were performed on equivalent stacks, i.e. Pt/M′O/MO_x/M. The influence of the in-situ formed metal oxide interface (MO_x) on the switching behavior of the stacks is discussed.