In last years interest to unstable semi-conductor alloys as to one of possibilities of nanoscale heterostructure production ha

In 80th years the direct evidence of homogeneous film dissociation to domains of various structure was shown by TEM. Before our work starts the images of InGaAsP layers that were grown in unstable region of phase diagram has been obtained by several research groups [13]. It was informed that TEM plane view images of such layers contain fine-scale structure (with period about 10 nm) and coarse-scale structure (with period about 100 nm) of intensity modulation along [100] and [010] directions. In the literature there are two opinions about these images. A number of authors suppose that coarse-scale modulation structure corresponds to solution modulation of unstable InGaAsP layer. Origin of fine-scale structure either are not explained or it is considered, that fine-scale modulation structure is inherent in all solid layers with three or more components. Another authors consider that only fine-scale structure correspond to solution modulation. And coarse-scale structure is consequence of layer dissolving and it can arise due to redistribution of strain fields in sample or curvature of samples surface. Our goal is to study influence of growth conditions on InGaAsP layer dissolving and to find out for us the nature of both modulation structures.