PREFERENTIAL EFFECTS IN ELECTRON-IRRADIATED SILICON DIOXIDE

Compositional depth profiles induced by electron irradiation in the near surface region (up to about 5 nm below the surface) of a thin SiO2 film have been measured. Nonmonotonic depth distributions have been obtained, which show an oxygen surface concentration spike and an oxygen depleted subsurface region. Such curves are interpreted as an explicit evidence for radiation induced oxygen segregation to the surface. This process may be assumed to play a very important role in the preferential loss of oxygen from electron irradiated SiO2.