Berlin 2008 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 13: Dielectric and ferroelectric thin films and nanostructures III

DF 13.2: Talk

Thursday, February 28, 2008, 14:20–14:40, EB 107

Characterisation of thin tantalum oxide films — •Katrin Bruder¹, Achim Walter Hassel¹, and Detlef Diesing² — ¹Max-Planck-Institut für Eisenforschung, Max-Planck-Str. 1, 40237 Düsseldorf — ²Institut für physikalische Chemie, Universität Duisburg-Essen, 45141 Essen

Metal-Insulator-Metal (MIM, consisting of tantalum– anodic tantalum oxide–platinum) contacts were investigated by means of IV characteristics and impedance spectroscopy. With impedance spectroscopy it is possible to determine the capacitance, the metals resistivities and the tunnel resistance. The latter one is a function of the bias voltage, while the capacitance and metals resistivities remain constant. The tunnel resistivity was found to have a maximum at a bias U_max slightly different from 0 V. This shift was investigated as a function of the film thickness (d=4 nm to 12 nm) and the temperature in the range from T = 58 K to 350 K. The measurements were compared to simulations. These simulations show, that for an explanation of this shift, asymmetrical barriers and tunneling through the valence band has to be considered.