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DS: Fachverband Dünne Schichten
DS 8: High-k and low-k dielectrics
DS 8.4: Talk
Monday, March 23, 2009, 16:00–16:20, WIL B321
The deposition of rare-earth oxide ultrathin-films with inorganic precursors — •Maraike Ahlf1, Hanno schnars1, Oliver Skibitzki1, Marvin Zöllner1, Katharina Al-Shamery1, Mareike Ahlers2, and Mathias Wickleder2 — 1University of Oldenburg, Institute for Pure and Applied Chemistry, Physical Chemistry I — 2University of Oldenburg, Institute for Pure and Applied Chemistry, Inorganic Chemistry
Semiconductor industry is searching for new materials as gate-oxides in MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) because the goal to shrink the size is limited due to the quantum mechanical tunnelling of electrons through a very thin oxide layer. Therefore it is necessary to replace the conventionally used gate-oxide material SiO2 by new metarials with higher κ-value and a bigger band gap, which could be rare-earth oxides (REO’s) e.g..To prevent interfacial layers of SiO2 in our investigation, the Si-wafers are prepared by a wet chemical etching using HF and NH4F before depositing new RE-based inorganic precursors. The mechanism of decomposition of RE-nitrates is studied in UHV by using STM, XPS and TPD. The used precursors are expected to decompose carbonfree to form the REO and gaseous decomposition products under mild, sputter free heating conditions. Deposition is done by using a liquid injection doser, drop-cast and dip applying different organic solvents. SEM and HRTEM images are utilized to assess the effectiveness of the different deposition conditions to form uniform, defectfree REO-ultrathin-films on Si with filmthickness of less then 10 nm state of the art related to our research.