A reinvestigation of Ni2Si thin film growth on Si(111) by TEM and RBS. Evidence of the presence of an interfacial NiSi layer prior to Ni consumption

The formation of Ni2Si films on Si(111) substrates at temperatures below 700 K is investigated by transmission electron microscopy and Rutherford backscattering spectrometry. The structure and morphology of the growing Ni2Si phase are analysed. A thin, epitaxial, interfacial NiSi layer of constant thickness of about 15 nm is detected at the Ni2Si/Si (111) interface, which is probably present from the very beginning of Ni2Si growth. Its structure and morphology are investigated, and its unexpected presence with respect to the generally accepted phase formation sequence is discussed.