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DF: Fachverband Dielektrische Festkörper

DF 12: High-k and Low-k Dielectrics II (Joint Session DS/DF)

DF 12.3: Vortrag

Mittwoch, 24. März 2010, 11:45–12:00, H8

Oxygen Engineering of HfO_2−x Thin Films grown by Reactive Molecular Beam Epitaxy — •Erwin Hildebrandt¹, Jose Kurian¹, Peter Zaumseil², Thomas Schröder², and Lambert Alff¹ — ¹Institut für Materialwissenschaft, TU-Darmstadt — ²IHP, Frankfurt, Oder

Reactive Molecular Beam Epitaxy (R-MBE) is an ideal tool for tailoring physical properties of thin films to specific needs. For the development of cutting-edge oxides for thin film applications a precise control of oxygen defects is crucial. R-MBE in combination with rf-activated oxygen allows reproducibly growing oxide thin films with precise oxidation conditions enabling oxygen engineering.

R-MBE was used to grow Hf and HfO_{2 ± x} thin films with different oxidation conditions on sapphire single crystal substrates. Structural characterization was carried out using rotating anode x-ray diffraction revealing highly textured to epitaxial thin films on c-cut sapphire. Furthermore, switching of film orientation by varying the oxidation conditions was observed demonstrating the role of oxygen in the growth procedure. The investigation of electrical properties using a four probe measurement setup showed conductivities in the range of 1000 µΩcm for oxygen deficient HfO_2−x thin films. Optical properties were investigated using a photospectrometer and additionally x-ray photoelectron spectroscopy was carried out to study the band gap and valence states. Both techniques were used to monitor the oxygen content in deficient HfO_2−x thin films. Our results demonstrate the importance of oxygen engineering even in the case of ’simple’ oxides.