FREEZING OF THE 2X1 STRUCTURE AT COMMENSURATE AG(100)-SI(100) INTERFACE

The growth process of Ag on the Si(100)2 x 1 surface is observed in situ by high-resolution reflection electron microscopy (HR-REM). A silver layer covers the Si(100) surface entirely at 1.5 ML (I ML = 6.78 x 10(14) atoms/cm2). Above 1.5 ML deposition, two-dimensional Ag islands are grown on the Ag layer of 1.5 ML at room temperature, while no islands are nucleated and grown on the layer at 480-degrees-C. Moire fringes appeared at the Ag islands seen in the HR-REM images and RHEED patterns show that the Ag islands after 3 ML deposition form a film with the (100) orientation and their (011) lattice planes are strained by 0.7% to be commensurate with the (011) Si lattice. The 2 x 1 structures of the Si(100) substrate are frozen at the Ag-Si interface, since the bright and dark contrast of the 2 x 1 domains of the clean surface is maintained.