SURFACE-STRUCTURES OF THE MG SI(100) SYSTEM STUDIED BY LOW-ENERGY-ELECTRON DIFFRACTION AND AUGER-ELECTRON SPECTROSCOPY/

Several reconstructed structures of the Mg/Si(100) system have been ob served by low-energy electron diffraction during the process of therma l desorption: (1) a (1 x 1) phase, (2) a (2 X 3) phase, (3) a (2 x 2) phase and (4) a second (2 x 3) phase. These phases appeared successive ly as the Mg coverage decreased. The thermal desorption spectra were m easured by a quadrupole mass spectrometer. The reconstructed structure s analyzed based on the Mg coverage suggest that Mg atoms on the Si(10 0)2 X 1 surface form atomic chains and the atomic arrangement on a cha in changes as the Mg coverage decreases. The reconstruction mechanism on the Mg/Si(100) system is very similar to that of the Ba and Sr/Si(1 00) system for the group II metals of the periodic table.