Observation of Atomic Structure by Scanning Tunneling Microscopy of Vicinal Si(100) Surface Annealed in Hydrogen Gas

Abstract
This paper reports on the atomic structure and adsorbed species on a vicinal Si(100) surface annealed in H2. Annealing was carried out at 1000–1200°C under the H2 pressure of 4–7 Torr. The annealing in ultrahigh vacuum (UHV) was also carried out for comparison. Reconstruction structures of 2×1 and 1×2 were found by scanning tunneling microscopy (STM) for the surface annealed in H2 as well as that in UHV. The most obvious difference of the H2-annealed surface from the UHV-annealed one is a large retreat of S A steps resulting in promotion of a biatomic step formation. Thermal desorption spectroscopy indicated the presence of a monohydride phase on the H2-annealed surface, which is consistent with the 2×1 structure observed by STM.