GROWTH AND CHARACTERIZATION OF THE RE SI(111) INTERFACE/

The structure and electronic properties of the interfaces formed by Re evaporation on clean Si(111)-7 x 7 and subsequent annealing were inve stigated by low energy electron diffraction (LEED), Photoelectron spec troscopy (XPS/XAES, UPS) and work function (WF) measurements. Rhenium was deposited from submonolayer up to 50 ML coverages and gradually an nealed up to 1100 K. Deposition causes rapid disappearance of the 7 x 7 reconstruction and the substrate UPS features, a gradual increase in the WF from 4.5 to 5.1 eV and negligible chemical shift in the XPS/XA ES peaks. The interface remained abrupt with no intermixing, as metall ic Re grew in a simultaneous multilayers fashion above 0.8 ML coverage . Annealing of 50 ML of Re causes a Si enrichment of the overlayer abo ve 600 K and the formation at around 950 K of a continuous layer of si licide which remains stable up to 1100 K, whereas annealing of Re laye rs close to 1 ML creates ReSi2 islands on the substrate surface.