ISSN:
0142-2421
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Physics
Notes:
Backscattering factor (R) between primary energies of 2-40 keV for film-substrate KLL Auger backscattering yield (RFS) is calculated via Monte Carlo simulation for C and Al films. Substrates ranging from Be (Z=4.0) to Au (Z=79.0) are used in the study. Results via a normalizedRFS (RN) function show that substrate effects are indeed present. This is especially so at higher primary energies and lower film atomic number. Electron range results also show that an important and meaningful quantity to describe the backscattering Auger yield with respect to film thickness is the mean backscattered energy penetration depth. This is found to be essentially different from the half-maximum electron range as proposed earlier. A power law can be used to describe the half-value range (i.e. the thickness for whichRN=0.5) with respect to primary energy. For Al film, however, a discontinuity in the power law is found for energies 〈4 keV. This is attributed mainly to the relatively large binding energy of the Al K-shell and also to the greater variation of the K-shell cross-section within the backscattered energy spectrum. A new analytical interpolation formula is proposed to calculateRFS. This model accounts for substrate effects at only primary energies 〉4 keV. At lower energies mean values are used instead. Besides the fitted parameters from our results, known bulkR expressions for film and substrate are also required for the practical use of the model.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
Permalink
