XPS analysis of ion‐beam‐induced oxidation of silicon substrates

XPS analysis was used to characterize Si (100) targets bombarded with an O 2 + beam with energies ranging between 5.00 and 0.50 keV and incident angles between 0° and 75°. In this energy range and at normal incidence a homogeneous SiO 2 layer is built up in a sequential suboxide replacement mechanism, while for bombardments at 5.00 keV and incident angles between 28° and 55° only a heterogeneous layer is formed. The latter contain elemental silicon, evenly spread in the altered layer, and all possible oxidized chemical states. For bombardments at high glancing angles (55°–75°) only a few suboxides are observed. Finally, a linear enhancement for the Si + secondary ion yield w.r.t. the Si 4+ relative concentration is found, except for very high Si 4+ level concentrations where a strong non‐linear increase takes place.