McNally, PJ;Tuomi, T;Lowney, D;Jacobs, K;Danilewsky, AN;Rantamaki, R;O'Hare, M;Considine, L

2001

June

Physica Status Solidi (A) Applied Research

Epitaxial lateral overgrowth of GaN on sapphire - An examination of epitaxy quality using synchrotron X-ray topography

Published

4 ()

VAPOR-PHASE EPITAXY DISLOCATION DENSITY LASER-DIODES GROWTH DIFFRACTION LAYERS FILMS TILT

185

373

382

Section transmission white beam X-ray topography was applied to the evaluation of the growth of GaN on sapphire using the epitaxial lateral overgrowth (ELO) technique. Using openings in 100 nm thick SiO2 windows, a new GaN growth took place, which resulted in nominal overgrowth thicknesses of 6.8 mum Measurements of the recorded Laue section topographs revealed misorientation between the epilayer and the substrate. Neglecting the misorientation contribution due to the 30 degrees rotation of the epilayer with respect to the substrate, the misorientation mechanism was found to be a consequence of lattice relation and dilatation. In the case of the ELO sample, these parameters varied with the stripe/window dimensions. The quality of the ELO epilayer is improved when compared to the non-ELO sample, though some local deviations from lattice coherence were observed. These results were complemented by observations made using X-rap diffraction and transmission electron microscopy.

BERLIN

0031-8965