IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Applied Surface Analysis Wednesday Sessions
       Session AS-WeA

Paper AS-WeA3
Fourier Modulus Brings Charging Samples, Auger Depth Profiles, Linear Least Squares and Factor Analysis Together

Wednesday, October 31, 2001, 2:40 pm, Room 134

Session: Depth Profiling II
Presenter: D.J. Pocker, IBM Storage Technology Division
Authors: D.J. Pocker, IBM Storage Technology Division
M.A. Parker, IBM Storage Technology Division
R.E. Davis, IBM Microelectronics Division
Correspondent: Click to Email
The shifting of Auger spectra has frustrated the extraction of chemically distinct depth profiles from charging samples using Linear Least Squares (LLS) or Factor Analysis (FA) methods. It is shown here that normal LLS or FA of the moduli (or magnitudes) of Fourier transforms of profile spectra readily yields such chemically distinct depth profiles. This approach applies equally to ESCA measurements and to line scans, maps and time sequence spectra. There are two requirements: The spectral energy window must be wide enough to capture the whole peak over its whole range of shifts. And, any given shifted spectrum cannot have stationary spectra or differently shifted spectra of other constituents superimposed on it.