Fabrication of freestanding {20$ \bar 2 $1} GaN substrates by HVPE using SiO2 masked GaN templates

Abstract

AbstractWe fabricated freestanding {20‐21}GaN substrates by a combination of selective area growth on patterned sapphire substrates by metal‐organic vapor phase epitaxy (MOVPE) and epitaxial lateral overgrowth by hydride vapor phase epitaxy (HVPE). The surface roughening and crack generation during the HVPE growth were successfully suppressed by the formation of SiO2 striped mask perpendicular to the a‐axis on the MOVPE‐grown {20‐21} GaN template. The HVPE‐grown {20‐21} GaN thick layer was polished by the chemical mechanical polishing and epi‐ready GaN substrates were obtained. Finally, a standard LED structure with InGaN/GaN multiple quantum wells was fabricated on our {20‐21} GaN substrate by MOVPE. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)