HREELS study of triethylphosphine (TEP) and tertiarybutylphosphine (TBP) on a Si(001)-(2 × 1) surface
Adsorption and decomposition of TEP and TBP on a clean Si(001)-(2 × 1) surface have been studied using high-resolution electron energy loss spectroscopy (HREELS). TEP is adsorbed molecularly at 300 K and decomposed into ethylene, which is evolved from the surface, through β-hydride elimination, leading to formation of SiH. TBP is partially dissociated at 100 K and decomposed into isobutylene (2-methylpropene) through the same mechanism as TEP. It is suggested that ethyl ( t-butyl) groups bonded to phosphorus in TEP are not transferred to silicon and ethylene (isobutylene) as a decomposition product is not re-adsorbed on the surface. This would be the reason why carbon deposition does not occur on the surface upon annealing the sample exposed to TEP and TBP.