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DS: Dünne Schichten

DS 31: Postersitzung

DS 31.15: Poster

Dienstag, 27. März 2001, 16:30–17:30, Foyer Saal 4

ANOMALOUS DAMAGING BEHAVIOUR OF AlAs DURING ION IMPLANTATION AT 15 K — •E. Wendler, W. Wesch, and B. Breeger — Friedrich-Schiller-Universität Jena, Institut für Festkörperphysik, Max-Wien-Platz 1, 07743 Jena

AlAs is implanted with 125 keV Na and 660 keV Xe ions at a temperature of 15 K. Defect analysis is done in situ by Rutherford backscattering spectrometry in channelling configuration without temperature change. An ion-beam-induced interfacial amorphisation of AlAs is observed at the interface to the GaAs cap layer, which is related to the energy deposition into collision processes, yielding an amorphisation rate of 0.44 nm/dpa (displacements per lattice atom). Over a wide range of ion fluences only point defects and point defect complexes exist in the implanted layer, pointing to a balance between defect formation and recombination during the irradiation. In this depth region amorphisation occurs if the volume introduced by the implanted ions exceeds some critical value. We assume that this causes the breaking of bonds in the AlAs lattice and the nucleation of amorphous seeds which grow rapidly during further irradiation.