UHV high-resolution electron microscopy and chemical analysis of room-temperature Au deposition on Si(001)-2×1

Investigations of Au on Si(001) have suggested that room-temperature deposition of Au on a clean Si surface results in an interfacial reaction and the formation of a gold-silicide. However, these investigations typically lack direct information about the surface morphology or the exact structure at the interface. Utilizing the capabilities of a surface chemical analysis system attached to a Hitachi UHV H-9000 microscope, a layer plus island growth mode has been observed by high-resolution electron microscopy showing multiply twinned small particles on the surface. The presence of small particles for various coverages has been correlated with the shifts seen in the Si 2p and Au 4f binding energies as well as the peak splitting in the Si LVV Auger transition. Our chemical data are consistent with observed shifts in the binding energies of small metal clusters deposited on various substrates, and with the published data for this surface. In addition, the results are consistent with our previous studies of Ag on Si(001), and indicate the growth morphology plays a crucial role in understanding spectroscopic information as well as its correlation to the structure and chemical state of the interface and surface morphology.