Morphology of Si 100/-2=1 surface with submonolayers of LiF studied by UHV-STM

The surface morphology of Si 100.-2=1 with submonolayers of LiF adsorbate and its annealing behavior are studied using scanning tunneling microscopy. LiF adsorbs randomly on the Si 100.-2=1 surface at room temperature RT., and the 2=1 structure disappears when the coverage of LiF is close to 1 monolayer. Interaction of the Si surface and the LiF adsorbate is enhanced by specimen annealing, which causes dissociation of the LiF and fluorination of the Si surface. Desorption of SiF xs1, 2, 3, 4.results in surface etching. After annealing at 7008C for 5 min, fluorine on the surface x decreased below the limit of the detection by X-ray photoelectron spectroscopy, and the Si surface is reconstructed to 2=1 at about 8008C. q2000 Elsevier Science B.V. All rights reserved