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Mayr M.,University AugsburgUniversitatsstrasse 186159 AugsburgGermany | Fischer M.,University AugsburgUniversitatsstrasse 186159 AugsburgGermany | Klein O.,University AugsburgUniversitatsstrasse 186159 AugsburgGermany | Gsell S.,University AugsburgUniversitatsstrasse 186159 AugsburgGermany | Schreck M.,University AugsburgUniversitatsstrasse 186159 AugsburgGermany
Physica Status Solidi (A) Applications and Materials Science | Year: 2015

Threading dislocations in off-axis grown heteroepitaxial diamond films have been visualized by preferential etching of the surface. The lateral distributions of the etch pits display characteristic inhomogeneities. Patterns with fourfold symmetry consisting of a cell structure with dislocation poor cores and dislocation rich walls aligned along [100] and [010] appear on (001) samples with off-axis tilt toward [110]. These patterns which developed after extended growth to a thickness of 1.5mm are mainly attributed to intrinsic anisotropies in the mutual interaction between neighboring dislocations via their stress fields. In contrast, growth on (001) surfaces with off-axis direction toward [100] yielded patterns with twofold symmetry. Here, the etch pits are aligned exclusively along the [100] off-axis direction which is attributed to the additional impact of the local surface inclination on the dislocations, resulting in an effective lateral movement during growth. Dislocation tilting in the local step-flow direction away from the crystallographic [001] axis, which provides a reasonable mechanism explaining the lateral movement, is confirmed by transmission electron microscopy. Homoepitaxial growth experiments on (001) surfaces 8° off toward [100] reveal etch pit patterns around "V" shaped microstructures that suggest a similar interpretation in terms of an effective lateral movement of dislocations induced by high local surface inclination. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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