FORMATION OF SM SILICIDES ON SI(111) - COMPOSITION AND EPITAXY

The formation of Sm silicides on Si(111) by means of solid phase epita xy has been studied with low energy electron diffraction, Auger electr on spectroscopy and photoelectron spectroscopy of the Sm 4f level and Si 2p level. A limited reaction is found to occur already at room temp erature whereas at higher temperatures a strongly intermixed Sm/Si lay er showing some long range order is formed. The Sm atoms of this inter mixed phase are found to be completely trivalent in accordance with ex pectations. The intermixed layer consists of two silicides with differ ent compositions, one of them being SmSi2-x, the other being tentative ly ascribed to SmSi.