ION-BEAM MIXING AND OXIDATION OF A SI GE-MULTILAYER UNDER OXYGEN BOMBARDMENT/

In many commonly used physical analysis techniques in semiconductor in dustry, low energy ion bombardment is used for material removal in dep th profiling. To know how the irradiation influences the material to b e investigated, it is necessary to gain insight in the processes takin g place during the interaction of the ion with the substrate. Silicon samples with a buried Ge-layer as a marker have been bombarded with 12 keV O2+ at different angles of incidence and analysed with in situ RB S. While under normal incidence a well-defined SiO2-layer with sharp i nterfaces is formed, for angles from normal incidence the oxygen incor poration decreases and Si-suboxides are seen by ex situ XPS. During ox ygen bombardment, when the silicon overlayer is converted to an oxide- layer, Ge migrates towards the surface before the sputter front has re ached the Si/Ge-interface. On the other hand, in the dilute limit Ge-s egregation to the interface is noticed under normal incidence.