Regensburg 2016 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 53: Postersession DS/HL
DS 53.3: Poster
Donnerstag, 10. März 2016, 16:00–19:00, Poster A
Stability of misfit dislocations in axial-heteroepitaxial 3C-SiC/c-GaN nanopillars and nanomesas — •Thomas Riedl1, Ricarda Kemper1, Andras Kovacs2, Doris Meertens2, Donat As1, and Jörg Lindner1 — 1University of Paderborn, Department of Physics, Warburger Straße 100, 33098 Paderborn, Germany — 2Ernst-Ruska Centre for Microscopy and Spectroscopy with Electrons, FZ Jülich, 52425 Jülich
GaN represents the most important compound semiconductor for realization of highly efficient blue LEDs and lasers. The cubic modification of GaN (c-GaN) has attracted growing interest due to the absence of internal electric fields. For the fabrication of high-quality semiconductor devices defect-free epilayers are essential. One way to avoid defects arising due to misfit is to reduce the lateral dimension of the layer to the nanoscale, which leads to a purely elastic relaxation in three dimensions.
In order to investigate the effect of the lateral size of axial pillar or mesa shaped heterostructures on the stability of misfit dislocations for the 3C-SiC/c GaN system, we apply various analytic approaches based on linear continuum elasticity theory. We find that the approaches of Glas and Ertekin predict the stability zone of misfit dislocations to exist at significantly smaller lateral dimensions and slightly larger layer thicknesses in comparison to the model of Zubia and Hersee. The former approaches yield a reasonable agreement with high-resolution TEM observations of c-GaN layers that have been grown on top of 3C-SiC mesa posts of different edge lengths.