Morphology of Si(100)-2 x 1 surface with submonolayers of LiF studied by UHV-STM

The surface morphology of Si(100)-2 X 1 with submonolayers of LiF adsorbate and its annealing behavior are studied using scanning tunneling microscopy . LiF adsorbs randomly on the Si(100)-2 X 1 surface at room temperature (RT ), and the 2 X 1 structure disappears when the coverage of LiF is close to 1 monolayer. Interaction of the Si surface and the LiF adsorbate is enhance d by specimen annealing, which causes dissociation of the LIF and fluorinat ion of the Si surface. Desorption of SiFx (x = 1, 2, 3, 4) results in surfa ce etching. After annealing at 700 degrees C for 5 min, fluorine on the sur face decreased below the limit of the detection by X-ray photoelectron spec troscopy, and the Si surface is reconstructed to ?,X I at about 800 degrees C. (C) 2000 Elsevier Science B.V. All rights reserved.