The growth of InxGa1-xN layers on c-plane GaN (2 mu m)/sapphire (0 00 1) substrates was carried out using the special growth system installed in an X-ray diffractometer using solely N-2 as the carrier gas. X-ray CTR scatterings on InxGa1-xN layer were measured at growth temperatures and after cooling down to room temperature. The differences in X-ray CTR scattering spectra at growth temperatures and at room temperature were discussed. The peak InN (0 0 0 2) or InGaN was observed at growth temperature. On the other hand, In (1 0 1) and In (0 0 2) peaks were observed with InN (0 0 2) or InxGa1-xN in the X-ray CTR spectra after cooling down to room temperature. These differences should be important to reveal the real growth processes of InxGa1-xN. Single diffraction peaks of In0.16Ga0.84N and In0 38Ga0.62N films were observed at 830 and 780 degrees C, respectively. (C) 2010 Elsevier By. All rights reserved.