Аннотация:We compare the shape of ordinary X-Ray diffractometry (XRD) rocking curves of crystals with SAS data. X-Ray rocking curves point out the difference in FWHM of those structures too. But results of measurement in bough case differ. It means that there was stress addition in widening of usual rocking curve of crystal films. Stress addition in widening of thin films was more than the same on thick films. It is explained by relaxation of stresses in thick films. Stresses in the film realize as domain segmentation. So on the size of natural superlattices in thin films were greater then in thick films. The model of the domain wall grids was proposed for GaN deposited on SiC and Al2O3.