  We explore the potential of Time-Of-Flight Medium Energy Ion Scattering
(TOFMEIS) for thin film analysis and analyze possible difficulties in
evaluation of experimental spectra. Issues regarding different combinations of
composition and stopping power as well as the influence of channeling are
discussed. As a model system high-k material stacks made from ultra-thin films
of HfO2 grown on a p-type Si (100) substrate with a 0.5 nm SiO2 interface layer
have been investigated. By comparison of experimental spectra and computer
simulations TOF-MEIS was employed to establish a depth profile of the films and
thus obtaining information on stoichiometry and film quality. Nominal film
thicknesses were in the range from 1.8 to 12.2 nm. As a supporting method
Rutherford-Backscattering spectrometry (RBS) was employed to obtain the areal
density of Hf atoms in the films.
