In the TEM plane view observation of phase separated microstructures in several regions of In0.525Ga0.475As layer grown at 310 degrees C by MBE on InP substrate, fine modulation is found in all the regions examined, but coarse modulation is found only in thick sections of TEM thin foils. These results strongly suggest that the coarse modulation in our sample is an artifact of thin foils which appears as a result of accommodation of the biaxial stress associated with the fine modulation.