range. The Auger peaks decay exponentially with overlayer cov­ the electron levels involved, is independent of the excitation erage, which is consistent with an exponential dependence of source and leaves the atom with a constant kinetic energy. The escape probability on the depth of the parent atom. A compila­ kinetic energy is given by the differences in binding energies for tion of data from a variety of sources has been used to generate the three levels (for example, EK-E L, - EL ) minus a correction 2 an escape depth curve which falls in the range of 5-30 A in the term for the work function and electron wave function relaxation. energy range from 0 to 3000 eV. The observed escape depth does When the Auger transition occurs within a few angstroms of the not show a strong dependence on the matrix.