Regensburg 2010 – scientific programme
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DS: Fachverband Dünne Schichten
DS 23: High-k and Low-k Dielectrics I (Joint Session DS/DF)
DS 23.4: Talk
Wednesday, March 24, 2010, 10:15–10:30, H8
A comparison of (SrO)x(ZrO2)(1−x) and ZrO2 as potential high-k dielectric for future memory applications — •Matthias Grube1, Dominik Martin1, Walter Michael Weber1, Thomas Mikolajick1, Lutz Geelhaar2, and Henning Riechert2 — 1Namlab GmbH, 01187 Dresden — 2Paul-Drude-Institut für Festkörperelektronik, 10117 Berlin
Following the demands of the aggressive downscaling of the capacitor area of dynamic random access memories, a material screening of novel high-k dielectrics with nanometer-scale thicknesses is required. Pure ZrO2 and admixtures with SrO are promising examples as possible substitutes for the established materials. Their growth, their physical and electrical characterization is our contribution to the screening. We employed molecular beam deposition to grow thin layers of (SrO)x(ZrO2)(1−x) on n++-Si substrates with a predeposited 5nm thin TiN layer as bottom electrode to realize metal-insulator-metal structures. An extensive physical characterisation consisting of X-ray diffraction, X-ray fluorescence analysis, X-ray reflectometry and atomic force microscopy was performed to verify the crystallinity, the stoichiometry, the physical thickness and the surface morphology of the dielectric film itself. The interface between the dielectric and the bottom electrode was investigated by transition electron microscopy. I-V and C-V measurements revealed k-values consistent to the literature for ZrO2. However, for (SrO)x(ZrO2)(1−x) rather low k-values below 9 for films up to 20 nm and much higher k-values of about 50 for films of 40 nm thickness were observed. Those dependencies will be discussed.
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