The structural property and interfacial morphology have been investigated for the Ca2Si/Mg2Si interface. The Ca2Si layers were grown on Mg2Si layers by heat treatment of the Mg2Si/Si substrates in Ca vapor. It is found that the CaMgSi phase is formed at the Ca2Si/Mg2Si interface. The structural property of the resultant silicides was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The chemical composition of the layers was examined by energy dispersion spectroscopy (EDS). In addition, the chemical analysis by X-ray photoelectron spectroscopy (XPS) revealed the Mg segregation on the silicide surface. The growth mechanism of Ca,Si on Mg2Si/Si is also discussed. (C) 2003 Elsevier Science B.V. All rights reserved.