LATERAL OVERGROWTH OF HIGH-QUALITY GAN LAYERS ON GAN AL2O3 PATTERNED SUBSTRATES BY HALIDE VAPOR-PHASE EPITAXY/

The growth of GaN thick layers by halide vapour-phase epitaxy (HVPE) o n metalorganic vapour-phase epitaxy (MOVPE)-GaN/Al2O3, substrates is r eported. In a first step, we have shown that lateral overgrowth was en hanced following preferential crystallographic directions. Double crys tal X-ray diffraction (DCXRD) assessment in omega scan showed full-wid th at half-maximum (FWHM) as small as 50 arcsec. On the way towards th e realisation of self-supported GaN substrates, the present study was extended to epitaxial lateral overgrowth (ELOG) on large surface GaN/A l2O3 patterned substrates to achieve coalescence. Structural, electric al and optical characterisation of such layers was performed, underlin ing the promising quality of these materials. (C) 1998 Elsevier Scienc e B.V. All rights reserved.