Optimization of HVPE growth of freestanding c-plane GaN layers using (100) γ-LiAlO2 substrates

Freestanding c‐plane GaN substrates are obtained using (100) γ‐LiAlO2 substrates due to spontaneous separation during post‐growth cool down. It is shown that by growth optimization the structural properties of 200 µm thick freestanding GaN layers can be improved resulting in FWHM values of ω‐rocking curves below 400 arcsec for 002 and 302 reflection and threading‐dislocation densities below 109 cm–2. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)