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Abstract: The intensities of the optical spectral lines emitted from a Ge(100) surface under Ar+ ion bombardment are studied as a function of the ion kinetic energy (1–5keV) and the partial pressure (5×10−6–5×10−4 Torr) of either germane or silane. For germane exposures, the Ge (GeI, 265nm and 304nm), H Balmer beta (486nm) and H Balmer gamma (434nm) optical lines are observed. For silane, additional peaks due to excited neutral Si (SiI, 288nm) and molecular SiH (A2Δ–X2Π, 414nm) are visible. The ion kinetic energy dependence of the GeI photon yields (265nm and 304nm) is analyzed in terms of the electron exchange mechanism. The similarity between the measured de-excitation parameters for germane and silane pressure between 5×10−6 and 5×10−4 Torr implies that the de-excitation mechanism does not change significantly. For both germane and silane exposures, the intensities of excited neutral Ge, H beta and H gamma optical lines increase with either larger partial pressures or ion kinetic energy. A similar trend is found for neutral SiI and molecular SiH emission during silane exposures. In contrast, the intensity of the H Balmer alpha transition (656nm) decreases with increasing incident ion kinetic energy at all measured partial pressures. Both trends are similar to that observed for either silane or germane exposed Si(100) surfaces under ion bombardment. [Copyright &y& Elsevier]

Abstract: The intensities of the optical spectral lines emitted from a Si(100) surface under Ar+ ion bombardment are studied as a function of the ion kinetic energy (1–5keV) and the partial pressure of germane. In these experiments, the ion flux is held constant while either the bombardment energy or the partial pressure of germane is varied. The excited neutral Si (SiI, 288nm), neutral Ge (GeI, 265nm and 304nm), H Balmer beta (486nm) and H Balmer gamma (434nm) optical lines are observed. With increasing germane partial pressure, a broad emission feature develops between 330 and 365nm and is assigned to excited GeH2 and/or GeH3 species. The emission intensities of the excited neutral Si, neutral Ge, Hβ and Hγ optical lines from the bombarded Si(100) surface increase with greater germane partial pressures and ion kinetic energy in a manner similar to that previously observed for silane exposures. In contrast to the monotonic increase of the above emission lines with higher germane partial pressures and greater incident kinetic energies, the H Balmer alpha (656nm) optical line exhibits unique behavior. Paralleling the behavior observed for silane exposed surfaces, the intensity of the Balmer alpha transition decreases with increasing incident ion kinetic energy at all measured partial pressures of germane. [Copyright &y& Elsevier]

The adsorption of cyanogen iodide (ICN) on a silicon (1 0 0) surface is studied by X-ray photoelectron spectroscopy (XPS), ultra-violet photoelectron spectroscopy (UPS) and temperature programmed desorption (TPD) spectroscopy. After submonolayer exposures, XPS indicates that the CN triple bond of ICN remains intact upon adsorption at 100 K. The UPS spectrum for submonolayer exposures at 100 K contains two peaks assigned principally to the π electrons in the CN triple bond. The splitting is due to the interaction between the π electrons of the cyanogen and the p electrons of the iodine. These results show that a portion of ICN molecules adsorbed molecularly. Higher exposures result in multilayer molecular ICN film. TPD spectra from both the submonolayer and multilayer films formed at 100 K show a peak at 170 K due to the desorption of adsorbed molecular ICN. In contrast to the low-temperature results, the UPS spectrum of ICN adsorbed at room temperature (RT) on Si(1 0 0) contains only one peak which originates principally from the π electrons in the CN triple bond. The lack of splitting in the RT UPS spectrum is a result of IC bond dissociation upon adsorption on Si(1 0 0). At RT the IC bond breaks while the CN bond remains intact. Upon annealing the Si(1 0 0) surface to higher temperatures, the UPS and XPS spectra indicate that the CN triple bond starts to disappear at ≈470 K. Simultaneous changes in the C 1s and N 1s photoelectron peaks between 470 and 800 K are consistent with the idea that CN bond cleavage in ICN is correlated with silicon carbide and nitride formation. By 800 K, all adsorbed CN species decompose completely into silicon carbide and nitride. [Copyright &y& Elsevier]