High quality AlGaN grown on ELO AlN/sapphire templates

U. Zeimera, V. Kuellera, A. Knauera, A. Mogilatenkoa, M. Weyersa, M. Kneissla,b

Published in:

J. Cryst. Growth, vol. 377, pp. 32-36 (2013).

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Abstract:

The defect structure and the homogeneity of 1-3 µm thick AlxGa1-xN layers grown on epitaxially laterally overgrown (ELO) AlN on patterned AlN/sapphire templates have been investigated in dependence on the miscut direction of the c-plane sapphire substrates, the etching depth into the sapphire and the Al concentration. It was found that shallowly etched AlN/sapphire templates with a 0.25° miscut toward the a-plane provide a smooth surface of ELO AlN and therefore a good Al homogeneity in the overgrown Al0.8Ga0.2N layer. The threading dislocation density in these layers is as low as 5 × 108 cm-2.

a Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
b Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstr. 36, 10632 Berlin, Germany

Keywords:

A1. Characterization; A1. Defects; A3. Epitaxial lateral overgrowth; A3. Metalorganic chemical vapor deposition; B1. AlGaN; B3. Light emitting diodes.