Structure investigations of nonpolar GaN layers.
The microstructure of nonpolar m-plane (1100) oriented GaN layers deposited on (100)gamma-LiAlO(2) 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 I(1) basal plane stacking faults (approximately 10(4) cm(-1)), threading dislocations (approximately 10(9) cm(-2)) as well as a complex defect network consisting of planar defects located on prismatic {1010} GaN and differently inclined pyramidal planes. A large number of the stacking faults nucleate at the GaN/LiAlO(2) 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.
Neumann
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W
Institut für Physik, Humboldt Universität zu Berlin, Berlin, Germany. wolfgang.neumann@physik.hu-berlin.de
Mogilatenko
A
A
Wernicke
T
T
Richter
E
E
Weyers
M
M
Kneissl
M
M