Plasmon Energy Shifts Research Articles

Investigation of titanium and titanium hydride by AES and EELS

Effects of hydriding on the Auger spectrum of titanium are investigated and can clearly be distinguished from the changes induced by oxygen contamination of the surface. New transitions occur about 5 eV below all transitions involving metal valence band electrons. Beam induced decomposition of the hydride could be avoided by proper experimental procedure. The composition of the investigated hydride was inferred from the measured bulk plasmon energy shift.

How epitaxial are Pd2SiSi interfaces?

Pd2Si layers produced by evaporation or sputtering onto silicon substrates were examined by high resolution electron microscopy, microdiffraction, X-ray, energy loss and Auger spectroscopy. The SiPd2Si interfaces produced by evaporation were in all cases rougher and more polycrystalline than those produced by sputtering. X-ray microanalysis showed the predictable variation in palladium distribution across the interface but quantification did not produce the expected palladium-to-silicon ratios, primarily because of probe broadening and X-ray-induced fluorescence. Energy loss spectra showed plasmon energy shifts and changes in Si L edge shape due to bond formation with palladium. Auger data provided evidence for a small amount of oxygen at the SiPd2 interface. Electrical measurements of the ideality factor for Schottky barriers made from these materials produced higher values for the rougher evaporation-formed interfaces consistent with interface-roughness-induced scattering and carrier recombination.

How Epitaxial Are Pd2Si–Si Interfaces?

Pd2Si layers produced by evaporation or sputtering onto silicon substrates were examined by high resolution electron microscopy, microdiffraction, X-ray, energy loss and Auger spectroscopy. The Si-Pd2Si interfaces produced by evaporation were in all cases rougher and more polycrystalline than those produced by sputtering. X-ray microanalysis showed the predictable variation in palladium distribution across the interface but quantification did not produce the expected palladium–to–silicon ratios, primarily because of probe broadening and X-rayinduced fluorescence. Energy loss spectra showed plasmon energy shifts and changes in Si L edge shape due to bond formation with palladium. Auger data provided evidence for a small amount of oxygen at the Si-Pd2Si interface. Electrical measurements of the ideality factor for Schottky barriers made from these materials produced higher values for the rougher evaporation-formed interfaces consistent with interface-roughness-induced scattering and carrier recombination.

Characterization of TiH x and TiD 0.9 surfaces: AES, ELS, SIMS and XPS studies

TiH x and TiD 0.9 surfaces have been characterized in UHV by Auger electron (AES), electron loss (ELS), secondary ion mass (SIMS) and X-ray photoelectron (XPS) spectroscopies. New features in the AES and XPS valence band spectra of the hydrides have been interpreted as indicating new peaks and changes in the valence band density of states with the presence of hydrogen or deuterium in the Ti interstices. Plasmon energy shifts, as determined by ELS, are shown to vary linearly with increasing hydridization, suggesting the free electron nature of the electrons added by hydrogen or deuterium. Shifts in the Ti 2p electron energy levels are also approximately linear with increase in H or D and suggest slight transfer of charge from Ti to H or D. Positive ion SIMS spectra of TiH x and TiD 0.9 show increases in the Ti isotopic peaks of 49, 50, 97 and 98 AMU with respect to the metal, reflecting differences in hydrogen or deuterium concentration.