Structure investigations of nonpolar GaN layers
W. Neumann1, A. Mogalitenko1, T. Wernicke2 , E. Richter2, M. Weyers2 and M. Kneissl2,3
Published in:
Journal of Microscopy, vol. 237, no. 3, pp. 308-313 (2010).
Abstract:
Summary:
The microstructure of nonpolar m-plane (100) oriented GaN layers deposited on (100)γ -LiAlO2 was analysed by transmission electron microscopy. This study shows that the films contain a large number of defects. The most dominant defects in the m-plane GaN are intrinsic I1 basal plane stacking faults (~104 cm-1), threading dislocations (~109 cm-2) aswell as a complex defect network consisting of planar defects located on prismatic {100}GaNand differently inclined pyramidal planes. A large number of the stacking faults nucleate at the GaN/LiAlO2 interface. Furthermore, the inclined planar defects act as additional nucleation sites for the basal plane stacking faults. A decreasing crystal quality with an increasing layer thickness can be explained by this defect formation mechanism.
1 Institut für Physik, Humboldt Universität zu Berlin, Berlin, Germany
2 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, D-12489 Berlin, Germany
3 Technische Universität Berlin, Institute of Solid State Physics. Berlin, Germany
Keywords:
Crystal defects, GaN, nonpolar films.
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