Formation of a Surface-Mediated Donor−Acceptor Complex: Coadsorption of Trimethylamine and Boron Trifluoride on the Silicon (001) Surface

The interaction of trimethylamine and boron trifluoride on the Si(001) surface has been investigated using X-ray photoelectron (XP) spectroscopy. XP spectra show the TMA forms a dative bond with the clean Si(001) surface, while on the clean surface BF 3 bonds dissociatively, yielding Si−BF 2 and Si−F species. If the surface is first “saturated” with TMA, however, BF 3 will continue to adsorb, giving rise to new F(1s) XP peaks. Based on an analysis of the energies and thermal behavior of these peaks, we propose that the adsorption of TMA and BF 3 on the Si(001) surface leads to the formation of a novel surface-mediated donor−acceptor complex of the structure TMA−Si−Si−BF 3 .