Full text loading...
Asymmetric (10−12) rocking curve of GaN films grown on vicinal sapphire (0001) substrates with various vicinal angles. The inset is the dependence of the FWHM of the symmetric (0002) diffraction peak on the vicinal angles.
Cross-sectional dark field TEM images of GaN films grown on (a) 0.5° and (b) 2.0° vicinal sapphire (0001) substrates under weak beam conditions. The TEM observations show the reduction of TD density in the GaN grown on a 2.0° vicinal substrate. Arrows in (b) indicate the position where macro-steps exist on the surface. In the TEM observations, the diffraction conditions were set to such a way that satisfied the Bragg condition, and the dark field images were taken using an beam.
Magnified cross-sectional dark field TEM image of a GaN film grown on a 2.0° vicinal sapphire (0001) substrate under the weak beam conditions. Arrows illustrate the positions where dislocation loops are formed by the VTD and the ITD. The observation conditions are the same as that described in the caption of Fig. 2.
Article metrics loading...