Silicon (001) surface after annealing in hydrogen ambient

We investigated Si surfaces after annealing in a H2 ambient using attenuated total reflection in the infrared region, reflective high energy electron diffraction, Auger electron spectroscopy, and atomic force microscopy. We found that at all H2 pressures the surface dangling bonds formed dimers that were related to two-domain (2×1) or c(4×2) reconstructed surfaces. H2 was adsorbed on the reconstructed surface and terminated a pair of dangling bonds that did not form dimers. H2 adsorption was limited by the reaction between H2 and the dangling bonds on the surface. The activation energy of H2 adsorption was 0.4–0.6 eV higher than that of H2 desorption. The surface on which H atoms were adsorbed and dimers were formed was inert, which kept the surface clean. We also found that the H2 annealed surfaces were influenced by surface roughness and contaminants including oxygen and carbon.