As a new method for fabricating gallium nitride (GaN) layers at the outer surface of silicon nitride (SiN) films, low-energy Ga ion irradiation on SiN films was performed, and the composition of the surface and the chemical-bond nature of the irradiated surfaces were measured by x-ray photoelectron spectroscopy (XPS). The peak position of the XPS spectrum of Ga 3d from the Ga irradiated SiN was shifted from the value of the metallic Ga to that of GaN, indicating the formation of GaN on the Ga irradiated SiN surface. Formation of GaN was also confirmed from the XPS spectra of N 1s signals. It was also found that a Ga irradiation energy up to 4 keV was useful to form GaN, and the implanted Ga atoms remained on the SiN surface as GaN after an annealing at 500 degrees C for 5 min under N-2 gas pressure of 1 X 10(-4) Torr. Because GaN which was formed is positioned at the outermost region of the Ga irradiated SiN films, the possibility to use this surface as a substrate for the GaN growth is discussed. (c) 2005 American Vacuum Society.