We have studied the reaction of molecular disilane with the germanium monodeuteride surface at 300 K. Temperature-programmed desorption and Raman spectroscopy suggest that the product of the reaction is a GeHD terminated surface. Ion scattering and Auger electron spectroscopies show that silicon does not accumulate on the surface but that it is incorporated into the near-surface (∼10 Å) region. We propose a mechanism involving silylene (SiH2) insertion and subsequent silicon indiffusion. We have also investigated the reactivity of this surface with disilane that has been activated by electron impact, producing a variety of dissociation products that were detected by mass spectrometry. The reactions of these radicals with the surface produced a complex mixture of surface species that included GeH, GeD and SiHx, as identified by Raman spectroscopy.

We present strong evidence, using low energy electron diffraction, temperature programmed desorption and Raman spectroscopy, for the formation of a dihydride-terminated Ge(1 0 0) surface phase that is stable in ultrahigh vacuum at room temperature. This phase was prepared by exposing the Ge(1 0 0) surface to a large fluence of atomic hydrogen generated by dissociation of molecular hydrogen on a tungsten filament. We observed a strong uptake dependence on filament placement and temperature and propose that the reason a number of previous reports did not observe this phase was an insufficient fluence of atomic hydrogen. Isotopic substitution of deuterium for hydrogen produced identical results and further allowed us to demonstrate that facile hydrogen abstraction may play an important role in the observed differences for hydrogen adsorption on the (1 0 0) surfaces of silicon and germanium.