Strain relaxation in Ga1-xInxN thin layers grown on GaN sublayers

The strain ratio versus crystallographic orientation is measured for 25-80- nm thick MOCVD ternary layers of Ga1-xInxN deposited on 3-mum thick buffer layer of GaN grown on the c-plane of sapphire. High resolution X-ray maps a nd diffraction profiles were measured for all basic crystallographic direct ions. Atomic force microscopy (AFM) measurements and simulations of the mea sured X-ray diffraction peaks are included. An analysis of the positions of diffraction maximums in the maps shows that no relaxation can be observed. A striking feature is the anisotropy of the values of the ratio measured f or different crystallographic configurations. (C) 2001 Elsevier Science BY All rights reserved.