ASYMMETRIC SB DIMERS ON THE 1-ML GE-TERMINATED SI(100) SURFACE

MeV transmission ion channeling has been used to investigate the struc ture of 0.95 ML of Sb deposited on 0.81 ML of Ge grown pseudomorphical ly on the Si(100) surface. It is shown that the sb overlayer is compos ed of asymmetric dimers, in contrast to the symmetric dimers reported in the literature on the Sb-terminated clean Si(100) surface. It is fu rther shown that the Ge reconstruction is lifted upon Sb deposition an d Ge then occupies a near-bulk site. The characterization of the under lying Ge layer provides additional and convincing evidence for Sb dime r asymmetry.