For the creation of memory cells of new generation, structurally perfect epitaxial Ge2Sb2Te5 (GST) layers and multilayered crystalline structures based on GeTe/Sb2Te3 superlattices grown on Si substrates are of interest. This initiates the studies of specific features of formation of such materials by various methods, including molecular-beam epitaxy. In this study, the structure of a thin (13-nm-thick) epitaxial GST layer to be used for the production of phase-change memory cells is investigated. The layers are grown by molecular-beam epitaxy on Sb-passivated Si(111) substrates. The studies are conducted by transmission electron microscopy and electron diffraction analysis of cross- and planar-section samples. The high resolution images of cross-section samples and the diffraction patterns for planar-section thin foils and their bright-field micrographs are obtained. It is found that the layer is composed of structurally …