Interfacial reaction of erbium on homoepitaxial diamond 100/ films

The atomic and electronic characteristics of homoepitaxial C 100.thin films and their reactions with very thin erbium deposits have been studied by low-energy electron diffraction LEED.and photoelectron spectroscopy X-ray photoelectron spectroscopywXPSxand ultraviolet photoelectron spectroscopywUPSx.. These films, of 3 mm thick, are grown by microwave chemical vapor deposition CVD.and p-doped 1017 Brcm3.. Measurements are made on two types of surfaces: plasma-hydrogenated and chemically oxidized. The hydrogenated surfaces exhibit 2 2=1.LEED pattern and negative electron affinity NEA.. Under annealing at high temperature 500–6508C. in oxygen 1 to 5=10y5 mbar., the hydrogenated surface is transformed slowly into an oxidized one which has the same atomic and electronic structures as the chemically oxidized surface, namely a 1=1.LEED diagram and a positive electron affinity PEA.. Under annealing at high temperature, erbium deposits react with the hydrogenated surface and not with the oxidized one. The reaction is not complete and produces a very thin interface erbium carbide layer. Internal photoemission measurements performed on erbium carbiderdiamond contacts, protected against oxidation by a layer of erbium silicide, show potential barrier heights close to 1.9 eV. q2000 Elsevier Science B.V. All rights reserved