AVS 50th International Symposium
    QSA-10 Topical Conference Tuesday Sessions
       Session QS-TuP

Paper QS-TuP9
Factors Influencing Angle Dependent XPS to Si Oxide Films

Tuesday, November 4, 2003, 5:30 pm, Room Hall A-C

Session: Aspects of Quantitative Surface Analysis
Presenter: N. Sanada, ULVAC-PHI, Inc., Japan
Authors: N. Sanada, ULVAC-PHI, Inc., Japan
A. Tanaka, ULVAC-PHI, Inc., Japan
A. Yamamoto, ULVAC-PHI, Inc., Japan
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The chemical structure and thickness of an ultra thin film with 1 to 3 nm on a crystalline semiconductor is of interest because its application in semiconductor industries such as gate oxide (including silicon oxy-nitride and high-k gate oxide) thin films and ultra thin passivation films. An XPS measurement is the peculiar nondestructive technique on the chemical in depth analysis of ultra thin films. In addition, XPS has advantages in reproducibility and sensitivity in theory compared with other non-destructive surface analysis techniques. By this means, XPS is anticipated as a tool to evaluate the chemical in depth analysis of the ultra thin films, especially in a measure of the industrial demand. We have gauged several latent variables in XPS measurements, for examples, photoelectron diffraction of crystalline silicon substrate, acceptance angle of the photoelectron analyzer, X-ray probe stability, and damages in the XPS measurement. Those issues are evaluated as a matter of fluctuation of the film thickness. The photoelectron diffraction of the substrate silicon is the heavy factor to fluctuate the analysis results. A commercial XPS instrument which has an acceptance angle with 4 degree in polar angle and 20 degree in azimuthal angles, even has 6% fluctuation in Si 2p photoelectron intensity of the substrate silicon at 45 degree in polar angle, which is confirmed by an experiment and a calculation. On the other hand, XPS measurement is evident to be reliable by avoiding the particular measurement angle and using an instrument with a wide acceptance in azimuthal angle. Finally, we applied the angle dependent XPS analysis to two-layered high-k gate oxide thin film with identical constituent elements for both layers. Those results will be discussed in detail.