In this paper, the behaviors of Indium overlayers on Si(111)7 x 7 and Si(100)2 x 1 surfaces have been investigated by low energy electron diffraction, electron energy loss spectroscopy, and auger electron spectroscopy. The behaviors of Indium, overlayers on Si(111) and Si(100) surfaces are different. At room temperature, an intermixed interfacial phase was formed during Indiurn adsorption on Si(111) surface, but Indiurn was not intermixed with Si substrate on Si(100) surface. At the temperature of similar to 550 degrees C and In coverage > 0.5 monolayer, the Si(100) surface could be completely faceted to {310} facets by Indium. (c) 2005 Elsevier B.V All rights reserved.