  Cross contaminations are observed on sample surfaces by AES and XPS, if
multiple samples are mounted on one sample holder and a neighbouring sample was
sputter depth profiled. During sputter depth profiling sputtered material is
deposited on inner surfaces of the instrument. In a secondary sputter process,
which is due to species leaving the primary sputter target with higher kinetic
energy, the previously deposited material is transported from the inner
surfaces to the other samples mounted on the sample holder. This Reflective
Sputtering is utilized to deposit ultra-thin layers on sample surfaces for XPS
binding energy referencing purpose and to build up ultra-thin conductive layers
to enable AES measurements on insulating samples.
