Growth of Nonpolar a-plane GaN Templates for HVPE Using MOVPE on r-plane Sapphire

In order to establish the growth of nonpolar GaN templates for subsequent overgrowth via hydride vapor phase epitaxy (HVPE) or subsequent device epitaxy we studied the growth of a-plane oriented samples on r-plane sapphire via metal organic vapor phase epitaxy (MOVPE). The growth parameters like reactor pressure, growth temperature and V/IIIratio for the nucleation layer as well as for the GaN main layer grown on top were systematically investigated. A 2 step growth procedure and SiN interlayers were introduced for defect reduction yielding to improved photoluminescence and x-ray rocking curve measurements. This also resulted in reduced in-plane anisotropy and surface roughness values. Hence we achieved high quality nonpolar a-plane GaN layers suitable for subsequent processes.