Diffraction effects in backscattering and Auger production near crystal surfaces

Computations have been made for 1 keV electrons of the dependence of the backscattering on the direction of the incident beam using the many-beam dynamical theory of electron diffraction. Values of the relevant absorption and backscattering parameters are given for electrons in this energy range. For the zero-loss component and the first bulk plasma loss component of backscattering the results of the computations are in moderately good agreement with experiment. The computed angular structure is considerably more pronounced than that observed but is rather sharp and may not be fully resolved in practice. The extension of the method to investigate the related angular effects observed in the Auger signal is discussed. It is suggested that the effect may be used to locate the position of Auger emitting atoms in the unit cell as well as their depth distribution near the surface of the crystal.