Silane adsorption of Si(001)2×1

Surface hydrogen coverage and the surface reconstruction of a silane-saturated Si(001)2×1 surface were investigated using the thermal-desorption-spectroscopy (TDS) and the reflection-high-energy-electron-diffraction measurements. The TDS spectrum mainly presented a single β1 peak around 520 °C, indicating the predominance of a Si monohydride phase on this surface. This observation agreed with the surface hydrogen coverage (H/Si=1.1–1.4) obtained from the integrated peak area of the TDS spectrum. By a repeated silane-saturation/thermal-desorption experiment, it was also clarified that all the hydrogen atoms in the silane molecules adsorb at this room temperature exposure. Adsorption mechanisms of silane molecules onto Si(001) surfaces are discussed and a model is presented based on the result.