Dresden 2009 – scientific programme
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DF: Fachverband Dielektrische Festkörper
DF 13: Thin Films and Nanostructures I
DF 13.5: Talk
Wednesday, March 25, 2009, 16:00–16:20, WIL B321
Conductive atomic force microscopy studies of leakage spot evolution in thin (ZrO2)x(Al2O3)1−x-films. — •Dominik Martin1, Oliver Bierwagen2, Matthias Grube1, Lutz Geelhaar3, and Henning Riechert3 — 1namlab Gmbh, D-01187 Dresden — 2University of California, Santa Barbara 93106 CA, USA — 3Paul-Drude-Institut für Festkörperelektronik, D-10117 Berlin
In order to achieve at the same time a high dielectric constant and a low leakage current in thin films, an understanding of the charge transport mechanisms is necessary for materials that are inhomogeneous on the nanoscale. Conductive atomic force microscopy (CAFM) measurements on ultrathin (ZrO2)x(Al2O3)1−x-films indicate a strong correlation between leakage spots and crystallites in an otherwise amorphous material. Regular local current-voltage curves were taken at amorphous matrix sites and local current-voltage curves were extracted from multiple images acquired at different biases. The comparison of hysteresis suggests stress induced leakage currents along filamentary leakage paths as well as charge trapping at grain boundaries. The overall local electronic behavior leads to the conclusion that leakage occurs preferably along boundaries between crystallites and the amorphous matrix and that leakage through grain boundaries is comparable to leakage currents through filamentary leakage paths formed by electrical stress.