Z. Liliental-Weber, M. Benamara, W. Swider, J. Washburn
Lawrence Berkeley National Laboratory
J. Park, P.A. Grudowski, C.J. Eiting, R.D. Dupuis
The University of Texas at Austin
This article was presented as part of Symposium W, "Gallium Nitride and Related Alloys" at the 1999 Fall Meeting of the Materials Research Society held in Boston, Massachusetts, November 28-December 3
Transmission electron microscopy was applied to study defects in laterally overgrown GaN layers, with initial growth on Al2O3 substrates followed by further growth over SiO2 masks. Dislocations found in the overgrown areas show changes in line direction. Most dislocations propagate along c-planes. In the overgrown material planar defects (faulted loops) are present on c-planes and their presence is most probably related to segregation of excess point defects and impurities present in this material. They appear to be initiated by the fast lateral growth. Some dislocations with screw orientation become helical resulting from climb motion. Formation of voids and also a high dislocation density was observed at the boundaries where two overgrowing fronts meet. Tilt and twist components were observed for these boundaries that were different for different overgrown strips grown in the same crystallographic direction suggesting that the GaN subgrain orientations on the two sides of a SiO2 mask are responsible for the final tilt and twist value.
Full text of this article is available.
For information about using Adobe Acrobat files, click here .
Cite this article as: MRS Internet J. Nitride Semicond. Res. 4S1, G4.6 (2000).
|
|
|
Reference List Building For information on building reference lists, see About the MIJ-NSR Reference List Builder |
