Auger Electron Spectroscopy and Rut herford Backscattering-Channeling Study of Silicon Nitride Formation by Low Energy N⁺₂ Ion Implantation

Direct nitridation of Si (100) surface by low energy N⁺₂ ion beam implantation at room temperature for differention doses and angles of incidence has been investigated by in-situ Auger electron spectroscopy and glancing Rutherford backscattering-channeling (RBS-C) measurements. The results show that with increase of N⁺₂ ion dose the N concentration in the Si surface increases and reaches to a surface stoichiometry close to that of Si₃N₄. The saturation dose and the thickness of the silicon nitride layer are related to the N⁺₂ ion energy. Complete nitride layer can be formed at incident angles of 0^o - 30^o. At larger angles the degree of nitridation decreases and no nitride layer could be found at incident angles larger than 54^o. The RBS-C results also suggest that a heavy damaged layer beneath the surface nitride layer can be formed due to ion beam implantation.