| AVS 54th International Symposium | |
| Surface Science | Wednesday Sessions |
| Session SS1-WeA |
| Session: | Reactions on Metal Surfaces |
| Presenter: | D. Kershner, University of Colorado at Boulder |
| Authors: | D. Kershner, University of Colorado at Boulder J.W. Medlin, University of Colorado at Boulder |
| Correspondent: | Click to Email |
A better understanding of metal-silicon and metal-SiO2 interfaces would be applicable in many areas of study. Due to the buried nature of these interfaces in applications, they have not been well studied. To study these interfaces, a model system consisting of sub-monolayer coverages of silicon containing molecules adsorbed on single crystal metal surfaces has been investigated, using the metal as the substrate rather than the silicon/silica. In this contribution, we report on a multi-technique surface science investigation of silane adsorption and reaction on clean and O-covered Pd(111). Silane adsorption on Pd(100) and other metals has been studied previously.1-3 These studies found that silane desorbs dissociatively, producing H adatoms and SiHX adsorbates at cold temperatures, followed by complete dissocation of the surface SiHX and the formation of a metal silicide phase at higher temperatures. Studies were performed using temperature programmed desorption (TPD), high resolution electron energy loss spectroscopy (HREELS), and auger electron spectroscopy (AES). SiH4 adsorption resulted in the formation of SiHX species on the Pd(111) surface stable to ca. 200K. Complete dissociation occurs upon heating, however it is unclear if a silicide is formed due to the lack of splitting in the Si LVV AES peak.4 Coadsorption of SiH4 and O2 leads to low temperature oxidation of surface Si atoms, forming a layer of SiOX. This is characterized by the presence of Si-O bonds in HREELS spectra and an AES feature at 84 eV.5 CO adsorption has also been used to probe of the effect of the SiOX layer on Pd surface chemistry. Density functional theory studies have also been performed to investigate the structures formed during surface silicon oxidation.
1 M.S. Nashner, J.C. Bondos, M.J. Hostetler, A.A. Gewirth, R.G. Nuzzo, Journal of Physical Chemistry B 102 (1998) 6202-6211.
2 C.J. Ennis, S.A. Morton, L. Sun, S.P. Tear, E.M. McCash, Chemical Physics Letters 304 (1999) 217-224.
3 E.M. Mccash, M.A. Chesters, P. Gardner, S.F. Parker, Surface Science 225 (1990) 273-280.
4 G.Y. Robinson, Applied Physics Letters 25 (1974) 158-160.
5 C.R. Helms, Y.E. Strausser, W.E. Spicer, Applied Physics Letters 33 (1978) 767-769.