AG ADSORPTION ON A SINGLE-DOMAIN SI(001)2X1 SURFACE STUDIED BY ELECTRON AND PHOTOELECTRON DIFFRACTION

The initial stages of Ag growth on a single domain (SD) Si(001)2 X 1 s urface have been studied by LEED, XPS and X-ray photoelectron diffract ion (XPD). It is observed that at room temperature (RT) Ag grows in th e Stranski-Krastanov mode with the first layer of similar to 1 monolay er coverage, with a SD 2 X 1 periodicity but the 1/2 order spots parti ally elongated, Annealing the RT deposited film to similar to 80 degre es C results in an intermediate layer with a well-ordered SD c(6 X 2) periodicity. The presence of c(6 x 2) phase has never been reported pr eviously for Ag/Si(001). Depositing Ag onto the substrate at similar t o 80 degrees C results in an intermediate layer with a SD 2 X 3 period icity. The Ag coverages for the SD c(6 X 2) and SD 2 X 3 phases are de termined to be the same. XPD shows that the local atomic arrangements of the two SD phases are different in spite of the proximity in covera ge and temperature of formation. Annealing the two SD phases to simila r to 300 degrees C results in a transformation into a double domain (D D) 2 x 3 phase with LEED spots partially streaked along the ''2 X'' di rection. XPS shows no change in Ag coverage for the transformation. De positing Ag onto substrates at temperatures greater than similar to 16 0 degrees C results in the DD 2 x 3 phase.