Regensburg 2019 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 25: Thin Film Properties: Structure, Morphology and Composition (XRD, TEM, XPS, SIMS, RBS, AFM, ...) Part II
DS 25.4: Vortrag
Freitag, 5. April 2019, 10:15–10:30, H32
HAXPES study of oxygen vacancies forming in thin film HfO2-based MIM structures — •Thomas Szyjka1, Ronja Hinz1, Mai Hussein1, Paul Rosenberger1, Marek Wilhelm1, Terence Mittmann2, Uwe Schröder2, and Martina Müller1,3 — 1PGI-6, FZ Jülich GmbH, Jülich, DE — 2NaMLab gGmbH, Dresden, DE — 3Fakultät Physik, TU Dortmund, Dortmund, DE
Hf-based dielectrics have replaced the traditional SiO2 and SiON as gate dielectric materials for conventional CMOS devices. Due to the recently discovered ferroelectric properties in strained HfO2, new applications like ferroelectric FETS are currently under development.
The ferroelectric properties are linked to the orthorhombic phase in HfO2 which can be stabilized via doping or the creation of oxygen vacancies. In this context, it is crucial to understand the processes and engineering of the interface properties of strained-HfO2 and electrode materials. Different thin film metal-insulator-metal (MIM) capacitors were fabricated with doped HfO2 using different electrode materials (TaN, TiN, IrO2) leading to various forming of oxygen vacancies. In addition, films with undoped HfO2 and TiN electrodes were fabricated using either no or 2 sccm additional oxygen flow during the fabrication in order to reduce the amount of oxygen vacancies. Hard X-ray photoelectron spectroscopy (HAXPES) was performed at DESY (Hamburg) and BESSY (Berlin) to analyse the interface processes. The spectral features of the Hf4f, N1s and O1s core levels indicate an intermixing of the layers and provide a direct relation between the growth process and the formation of oxygen vacancies.