Si(100) surfaces in a hydrogen-based process ambient

We studied the atomic surface properties of Si(100) during preparation in a (metal-organic) vapor phase epitaxy (VPE) reactor and the impact of the hydrogen ambient. Absorption lines in Fourier-transform infrared spectra were identified as stretch modes of coupled Si–H monohydrides, in agreement with Si-dimers observed by scanning tunneling microscopy. The polarization dependence of the antisymmetric stretch mode distinguished different dimer orientations and verified a clear preference for one of the (2×1)/(1×2) surface reconstruction domains. Tip-induced H-desorption proved the complete saturation of dangling bonds after VPE-preparation. In situ reflectance anisotropy spectroscopy showed the absence of Si–H bonds at elevated annealing temperature.