Reaction of N2+ beams with aluminum surfaces

Publisher Website
Google Scholar
Abstract
Reactions of N2 +ion beams with the surface of clean polycrystallinealuminum over the energy range of 300–4000 eV are studied by the techniques of x‐ray and UVphotoelectron spectroscopy (XPS and UPS) and Auger electron spectroscopy(AES). The reaction produces a nitride layer which the depth–concentration profiles reveal to be a superposition of two distributions: the first is a continuous AlN phase at the near surface to a depth of ∼20 Å and the second is a region of lower nitrogen concentration tailing deeper into the Al substrate where a complete AlN phase has not been established. The AlN film is characterized by the agreement of the binding energies of the N 1s (397.3 eV) and Al 2p (74.1 eV) lines, of the kinetic energy of the AlK L L line (1338.9 eV), and of the Auger parameter (1463.0 eV) with a known standard of AlN. The N/Al ratio initially increases linearly with the nitrogen ion dose at low concentrations and finally reaches a steady state condition, determined by the opposing rates of nitridation and sputtering by impinging ions, at a dose of ∼1×1016 ions cm−2. The reaction cross section is found to vary from 2.0×10−16 to 4.7×10−17 cm2 over the ion energy range of 0.3–1.0 keV. A reaction mechanism which is supported by these results is discussed.