Seminar Announcement: Mathias Wickleder

Data pubblicazione: 19-nov-2019 13.53.33

Announcement

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,

Germany

Abstract

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.