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Seminar Announcement: Mathias Wickleder

posted Nov 19, 2019, 5:53 AM by Stefano Varas   [ updated Nov 19, 2019, 5:53 AM ]

Friday, 15 November 2019, 15:00
Sala Grande Palazzina B via alla Cascata 56/C

"Precursors for Rare Earth Oxides - New Routes to ultrathin Oxide Layers"

Mathias Wickleder
Department of Chemistry,
University of Cologne,

Rare earth oxides have attracted considerable attention as so called high-k materials. These compounds exhibit very high dielectric constants that are mandatory for further miniaturization of electronic devices. Especially for field effect transistors ther e is strong need for ultrathin films of high-k oxides on silicon surfaces. There are several methods to produce these layers, like atomic layer deposition (ALD) and chemical vapor deposition (CVD). Our research is directed to the development of a more simp le process that allows for the preparation of thin carbon-and-chlorine-free layers. Following these aims we are investigating m olecular nitrates and perchlorates according to the general formula M(NO3)3·xL and M(ClO4)3·xL, where M is a rare earth metal an d xL is a variable number of solvent ligands. These compounds usually show the M3+ ions coordinated by three chelating nitrate groups and the solvent molecules leading to high coordination numbers We used the DME compound La(NO3)3·2DME as a precursor for the deposition of La2O3 on H-terminated silicon surfaces. It turned out that the simple procedure leads to La2O3 layers with a thickness below 10 nm.

Stefano Varas,
Nov 19, 2019, 5:53 AM