Silicate formation at the interface of Pr-oxide as a high-K dielectric and Si(001) surfaces

The composition and chemical bonding of the first atoms across the interface between Si(001) and the dielectric determine the quality of dielectric gate stacks. An analysis of that hidden interface is a challenge as it requires both, high sensitivity and elemental and chemical state information. We used X-ray absorption spectroscopy in total electron yield and total fluorescence yield at the Si2p and the O1s edges to address that issue. We report on results of Pr2O3/Si(001) as prepared by both, epitaxial growth and metal organic chemical vapor deposition (MOCVD), and compare to the SiO2/Si(001) system as a reference. We find evidence for the silicate formation at the interface as derived from the characteristic features at the Si2p and the O1s edges. The results are in line with model experiments in which films of increasing film thickness are deposited in situ on bare Si(001) surfaces.