Regensburg 2004 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 9: Dünnschichtanalytik II

DS 9.3: Vortrag

Montag, 8. März 2004, 15:45–16:00, HS 32

Structure and thickness-dependant lattice parameters of ultra-thin epitaxial Pr₂O₃ films on Si(001) studied by SR-GIXRD — •Thomas Schroeder¹, Tien Lin Lee¹, Laure Libralesso¹, Jörg Zegenhagen¹, Peter Zaumseil², Christian Wenger², and Hans Joachim Müssig² — ¹E.S.R.F., Beamline ID 32, 6, Rue Jules Horowitz, 38043 Grenoble, France — ²IHP, Im Technologiepark 25, 15236 Frankfurt (Oder)

Heteroepitaxial Pr₂O₃ films on Si(001) show promising results for applications as high-K dielectrics in future silicon-based microelectronics devices. To solve the epilayer structure and monitor the evolution of the lattice parameters over the technologically important thickness range from 1 to 10 nm, a Synchrotron-grazing incidence X-ray diffraction (SR-GIXRD) study was performed. The oxide film structure is characterized by the growth of the cubic Pr₂O₃ phase (Ia3) with its rectangular (101) plane on the Si(001) substrate. The resulting two orthogonal rotation domains of the oxide layer are identified by the four-fold symmetry of the oxide reflections. The azimuthal orientation of these oxide domains is determined by measuring the oxide in-plane reflections. These in-plane measurements together with theta - 2theta scans allow to monitor the evolution of the oxide unit cell lattice parameters as a function of film thickness. The transition from almost perfect pseudomorphism to bulk values is detected from 1 to 10 nm film thickness. The intensity analysis of the oxide reflections points to a change in the structure factor of oxide films thinner than 4 nm, probably due to silicate formation at the oxide / Si interface.