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Thickness-fringe Contrast Analysis of Defects in GaN

Published online by Cambridge University Press:  18 March 2011

Jeffrey K. Farrer
Affiliation:
Dept. of Chemical Engineering and Materials Science, University of Minnesota421 Washington Ave. S.E., Minneapolis MN 55455, USA
C. Barry Carter
Affiliation:
Dept. of Chemical Engineering and Materials Science, University of Minnesota421 Washington Ave. S.E., Minneapolis MN 55455, USA
Z. Mao
Affiliation:
Dept. of Chemical Engineering and Materials Science, University of Minnesota421 Washington Ave. S.E., Minneapolis MN 55455, USA
Stuart McKernan
Affiliation:
Dept. of Chemical Engineering and Materials Science, University of Minnesota421 Washington Ave. S.E., Minneapolis MN 55455, USA
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Abstract

The analysis of thickness-fringe contrast in weak-beam transmission electron microscope (TEM) images has been shown to be a reliable method for the complete determination of the character, as well as the magnitude, of a dislocation Burgers vector. By selecting multiple diffraction conditions and, for each condition, determining the number of terminating thickness fringes at the exit of a dislocation from a wedge-shaped sample, the Burgers vector can be unambiguously determined. Defect analysis of GaN pyramids grown on (111)Si by the lateral epitactic overgrowth (LEO) technique reveals a core region which contains a relatively high density of dislocations and a lateral-growth region where the defect density is decreased. The thickness-fringe contrast technique was used in the lateral growth regions of the pyramids to analyze the dislocation Burgers vectors.

Type
Research Article
Copyright
Copyright © Materials Research Society 2001

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References

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