AN XPS AND WF STUDY OF THE ER SI(100) INTERFACE FORMATION/

XPS and work function measurements were used to investigate the Er/Si( 100) interface formation after Er deposition up to 9 ML between 250 an d 500 K and subsequent annealing up to 970 K. Erbium initially adsorbs as isolated adatoms with a dipole moment of 1.1+/-0.5 D. The Er-Si in teraction above 1 ML leads to an interface silicide plus an intermixed dilute Si phase extending up to similar to 5 ML at 370 K. Upon anneal ing, the intermixed phase becomes more dense in Si, extends up to the surface and eventually turns into a silicide with a WF of 4.8 eV. The XPS results are in agreement with the literature on Er/Si(lll) and oth er rare-earth/silicon systems, whereas the WF results demonstrate the usefulness of WF measurements in the study of RE/Si interfaces.