X-ray Photoelectron Spectroscopy of silicon oxynitride layers obtained by low-energy ion implantation

Simultaneous oxygen and nitrogen low-energy ion implantation in silicon single crystals have been used to obtain surface layers of silicon oxynitride. In-depth concentration profiles, measured by XPS, showed all the possible tetrahedral configurations of silicon with the neighboring atoms. The most important feature of these profiles has been found to be the accumulation of a so-called Si³⁺ state just below the surface and about 20 nm deep. This amphoteric state has interesting properties for impurity passivation or electron trapping.