X‐ray diffraction study of gallium nitride grown by MOCVD

Abstract
An X‐ray diffraction study of gallium nitride grown on the c‐plane (0001) and r‐plane (0112) of sapphire substrates by metal organic chemical vapour deposition using triethylgallium and ammonia was performed. By measuring asymmetric reflections with a ω‐2θ two‐circle diffractometer, lattice constants of α‐GaN could be resolved for both substrate orientations and the epitaxial relationships could be confirmed. Additionally, the existence of β‐GaN on the r‐plane sapphire substrate could be determined. Pole figure measurements show different qualities of in‐plane orientation of the α‐GaN layers for the two substrate orientations.