HREELS STUDY OF TRIETHYLPHOSPHINE (TEP) AND TERTIARYBUTYLPHOSPHINE (TBP) ON A SI(001)-(2X1) SURFACE

Adsorption and decomposition of TEP and TBP on a clean Si(001)-(2 x 1) surface have been studied using high-resolution electron energy loss spectroscopy (HREELS). TEP is adsorbed molecularly at 300 K and decomp osed into ethylene, which is evolved from the surface. through beta-hy dride elimination, leading to formation of Si-H. TBP is partially diss ociated at 100 K and decomposed into isobutylene (2-methylpropene) thr ough the same mechanism as TEP. It is suggested that ethyl (t-butyl) g roups bonded to phosphorus in TEP are not transferred to silicon and e thylene (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.