Dresden 2006 – scientific programme

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DS: Dünne Schichten

DS 15: Thin magnetic films

DS 15.4: Talk

Wednesday, March 29, 2006, 16:45–17:00, GER 38

Rare-Earth Scandate Multi-Layer Thin Films prepared by Pulsed Laser Deposition — •T. Heeg¹, J. Schubert¹, Ch. Buchal¹, M. Boese², and M. Luysberg² — ¹Institut für Schichten und Grenzflächen ISG1-IT/CNI, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany — ²Institut für Festkörperforschung IFF, ER-C and CNI, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany

The rare-earth scandates have gained considerable attention as candidate materials for the replacement of SiO₂ in silicon MOSFETs in either amorphous or epitaxial form. In this work, amorphous as well as epitaxial multi-layer systems consisting of scandate and titanate layers were grown in situ on different substrates using PLD. BaTiO₃ was used in combination with GdScO₃, and SrTiO₃ was combined with DyScO₃. The thickness ratio and the total number of layers were varied. RBS and RBS/channeling were used to investigate the stoichiometry and crystal quality of the films. XRD measurements were performed to analyze the crystal structure. HRTEM was used to get detailed information on the orientation relationship between scandate and titanate layers as well as on the strain present in the layers.

To determine the electrical properties of the amorphous multi-layer films on silicon substrates, the results of several samples with a thickness from 26 nm to 100 nm have been evaluated using an EOT plot. To investigate the dielectric properties of the epitaxial films, SrRuO₃ covered SrTiO₃(100)-substrates were used for the electrical characterization. The amorphous films have a dielectric constant of 35, whereas the epitaxial films show a higher value of 60.