LATERAL OVERGROWTH OF GAN ON PATTERNED GAN SAPPHIRE SUBSTRATE VIA SELECTIVE METAL-ORGANIC VAPOR-PHASE EPITAXY - A ROUTE TO PRODUCE SELF SUPPORTED GAN SUBSTRATES/

In the present paper we propose to extend the selective epitaxy of GaN to the lateral overgrowth and to take advantage of the growth anisotr opy to produce strain free GaN crystals. After filling the openings in a dielectric mask by selective epitaxy, lateral overgrowth occurs ref lecting the growth anisotropy. This allows the fabrication of samples with non-planar geometry. The selective epitaxy was achieved by metal organics vapour phase epitaxy (MOVPE) whereas lateral overgrowth until island coalescence was carried out either by MOVPE or halide vapour p hase epitaxy (HVPE). A GaN epitaxial layer is first grown using atmosp heric pressure metalorganic vapour phase epitaxy on {0 0 0 1} sapphire . The dielectric film is silicon nitride. The openings are achieved us ing standard photolithographic technology. These openings reveal free GaN surface and are used for epitaxial regrowth by MOVPE, and then by HVPE. (C) 1998 Elsevier Science B.V. All rights reserved.