Material quality improvement for homoepitaxial GaN and AlN layers grown on sapphire-based templates

Homoepitaxial growth of GaN and AlN was under investigation. GaN homoepitaxial layers were grown by both metal organic chemical vapour deposition (MOCVD) and hydride vapor phase epitaxy (HVPE) on GaN‐on‐sapphire templates. AlN homoepitaxial layers were grown on AlN‐on‐SiC templates, AlN‐on‐sapphire templates, and AlN bulk substrates. Both GaN and AlN templates were grown by HVPE. Crystal structure, defects, and optical properties of grown layers were studied. For GaN homoepitaxial growth processes pretreatment procedures were developed to improve materail quality and avoid layer cracking. It was observed that defect density is reduced by homoepitaxy. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)