Regensburg 2016 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 12: Postersession DS

DS 12.40: Poster

Montag, 7. März 2016, 17:00–19:00, Poster A

Investigations of defects in weakly damaged ion implanted GaAs — •Sascha Creutzburg¹, Emanuel Schmidt¹, Ingo Uschmann², and Elke Wendler¹ — ¹Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena — ²Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena

In case of room temperature ion implantation of GaAs, a saturation of defects at a rather low level without amorphization is observed, the microstructure of which is not yet understood. The aim of the present work is to investigate this state of weak damage in GaAs by RBS-channelling, optical, TEM, XRD and in-situ stress measurements. Undoped <100> oriented GaAs wafers were implanted with 1 MeV Si⁺ at room temperature to ion fluences between 1·10¹³ cm^-2 and 3·10¹⁵ cm^-2 with constant ion flux. The energy dependence of the minimum yield as measured by RBS-channelling indicates the presence of correlated displaced atoms. This is in agreement with previously performed temperature dependent RBS-channelling measurements. The near edge absorption coefficient K shows an exponential behaviour of the photon energy ℏ w according to K∼exp(ℏ w/E) with the tailing energy E=(0.36−0.51) eV depending on the ion fluence. Theoretical considerations have shown that the range of tailing energy can be explained assuming a high concentration of antisite defects and vacancies. Further information about lattice strain within the implanted layers will be obtained by ex-situ XRD rocking curve measurements and by in-situ measurements of the sample curvature.