Auger spectroscopy thermodesorption of Sb on Si1−xGex layers grown on Si(1 0 0) substrates

Desorption of Sb from Si1−xGex layers (x=0, 0.05, 0.1, 0.2, 1) grown by molecular beam epitaxy (MBE) on Si(1 0 0) substrates is investigated using Auger electron spectroscopy thermodesorption (TD-AES). Sb desorption process on Si1−xGex is well described by a first-order reaction. No extra TD-AES peaks are observed on Si1−xGex compared to Si. For 1 ML of Sb coverage the TD-AES peak shifts to lower temperature when Ge bulk concentration increases. The Sb monolayer desorbs at 801, 752, 740, 715, and 706 °C for x=0, 0.05, 0.1, 0.2 and 1, respectively. We explain the non-linear decrease of the Sb desorption energy when x increases by the strong Ge surface segregation during the MBE growth of Si1−xGex layers, resulting in an almost pure Ge surface even for low x.