Coefficient of Elastic Backscattering Electrons
- Practical Electron Microscopy and Database -
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The coefficient of elastic backscattering electrons, r =ie/ii. .Here, ie is the beam current of elastic backscattering electrons and ii is the beam current of incident electron beam.

The coefficient r depends on the energy (E0) of incident electron beam, angle of incident electron beam, chemical composition, and state and structure of the irradiated sample’s surface. For instance, single crystals are anisotropic with respect to the direction of moving electrons. During the electron motion along the channels of crystal structures formed by closely packed chains of atoms, the probability of electron scattering and atom ionization increases (so called channeling effect). In addition, electron diffraction in the crystal lattice is observed. As a result of the two phenomena, the dependence of r(E0) on the angle of the incident electron beam has a complex shape, with several maxima and minima as shown in Figure 4814). Furthermore, the coefficient of r usually given for polycrystals are usually averaged over various directions.

Dependence of σ on the angle of incidence Electron emission Coefficient

Figure 4814. Dependence of r on the angle (Φ) of incident electron beam for single silicon crystals at a voltage of 1 keV. Note that σ (overall electron emission coefficient) and η (coefficient of inelastic backscattering electrons) are discussed on the relevant pages of the book.


 

 

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