In this study, InP(100) surfaces were bombarded by argon ions in ultra high vacuum. Indium metallic droplets were created in well controlled quantities and played the role of precursors for the nitridation process. A glow discharge cell was used to produce a continuous plasma with a majority of N atomic species. X-ray photoelectron spectroscopy (XPS) studies indicated that the nitrogen combined with indium surface atoms to create InN thin films (two monolayers) on an In rich-InP(100) surface. This process occurred at low temperature: 250°C. Synchrotron radiation photoemission (SR-XPS) studies of the valence band spectra, LEED and EELS measurements show an evolution of surface species and the effect of a 450°C annealing of the InN/InP structures. The results reveal that annealing allows the crystallization of the thin InN layers, while the LEED pattern shows a (4×1) reconstruction. As a consequence, InN related structures in EELS and valence bands spectra are different before and after the annealing. According to SR-XPS measurements, the Fermi level is found to be pinned at 1.6eV above the valence band maximum (VBM).