RECONSTRUCTIONS AND GROWTH OF AG ON SI(001)(2X1)

Complex growth and reconstructions of Ag on Si(001)(2 X 1) were studie d by STM, LEED, AES and SEM. We find that Ag is first adsorbed at the silicon SB step edge and preferentially forms dimers on the Si terrace s. At room temperature Ag grows in a pseudo Stranski-Krastanov (SK) mo de. The first layer is not homogeneous and does not cover the substrat e completely. In this layer several different structures coexist (e.g. (2 X 2), c(4 X 2), depending on the Ag induced buckling of the Si dim er rows). During the formation of the inhomogeneous layer, three-dimen sional islands grow with the orientation Ag(111)//Si(001). At a substr ate temperature of 770 K real SK growth is observed and the first laye r is homogeneous. This layer has a (2 X 3) structure. On the top of th is (2 X 3) layer, Ag islands grow with Ag(001)//Si(001).