Auger and electron energy-loss study of the Pd/SiC interface and its dependence on oxidation

Abstract

Auger and electron energy-loss spectroscopies have been used to observe the formation and oxidation of the Pd/SiC interface. The interface is reactive at room temperature, and intermixing produces a surface phase consisting of Pd silicide with some dissolved C. The dependence of the Si(L 2,3VV) lineshape on Pd coverage and on annealing suggests that the local environment of Si in the silicide is that of a mixture of Pd 3Si and Pd 4Si rather than that of Pd 2Si, which is formed when Pd is deposited on elemental Si. There is no indication of Pd carbide formation even after annealing at ∼800°C. Oxidation-induced changes in the spectra indicate that (for room-temperature exposures up to 10 6 L (=1 Torr s)) adsorption occurs preferentially on Si sites.