Interaction of low-energy nitrogen ions with GaAs surfaces.

We have studied the interaction of low-energy nitrogen ions (0.3–2 keV N₂⁺) with GaAs (100) surfaces by photoemission spectroscopy (PES) around N 1s and Ga 3d core levels and near-edge x-ray absorption fine structure (NEXAFS) around the N K edge. At the lowest bombardment energy, nitrogen forms bonds with both Ga and As, while Ga-N bonds form preferentially at higher energies. Thermal annealing at temperatures above 350 °C promotes the formation of GaN on the surface, but it is insufficient to remove the disorder introduced by ion implantation. Nitrogen interstitials and antisites have been identified in NEXAFS spectra, while interstitial molecular nitrogen provides a clear signature in both PES and NEXAFS. [ABSTRACT FROM AUTHOR]