The effect of AlN buffer layer on GaN grown on (111)-oriented Si substrates by MOCVD

GaN films were grown by metal organic chemical vapor deposition on (1 1 1)S i substrates, using AlN as a buffer layer. The influence of the AIN buffer layer growth temperature and growth duration on the morphology and preferre d orientation of GaN films was studied. Drastic enhancement of epitaxial re gistration was observed with increasing buffer growth temperature. A sharp transition in the growth mode occurred at 760 degrees C. For that temperatu re, an optimal buffer layer growth duration was found. The use of March par ameter as a figure of merit in X-ray diffraction testing of textured GaN fi lms is proposed. (C) 2000 Elsevier Science B.V. All rights reserved.