Regensburg 2002 – scientific programme
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HL: Halbleiterphysik
HL 38: Poster 2
HL 38.55: Poster
Thursday, March 14, 2002, 16:30–19:00, Poster A
Nondestructive analysis of misfit dislocation densities in II-VI heterostructures by diffuse x-ray scattering — •Gabriela Alexe1, Heidrun Heinke1, Matthias Klude1, Vladimir M. Kaganer2, and Detlef Hommel1 — 1Institut für Festkörperphysik, Universität Bremen, KufsteinerStraße NW1, 28359 Bremen — 2Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz5-7, 10117 Berlin
The dislocation densities in epitaxial heterostructures are often determined either by counting etch pit densities or by transmission electron microscopy. We present studies on a nondestructive method for the estimation of dislocation densities by using the diffuse scattered x-ray intensity, which has been applied for different types of ZnSe based heterostructures grown by molecular beam epitaxy on GaAs(001) substrates. The diffuse x-ray scattering is sensitive to low densities of misfit dislocations which occur in the early stage of strain relaxation in epitaxial layers. While this has been used hitherto only to qualitatively detect changes in defect densities, for instance in ZnSe layers on GaAs substrates after thermal treatment, a quantitative approach would be very useful. Both a detailed comparison of experimental data with theoretical profiles of the diffuse scattered intensity, simulated by a model considering 60∘ glide dislocations, and the application of alternative experimental methods, as x-ray topography or cathodoluminescence, for the detection of misfit dislocations or other extended defects are realised for this purpose.