Formation of hydrogen-free gallium nitride (GaN) thin layers by ion beam direct deposition method under nitrogen ambient was investigated. After a G ion beam at an energy of 100 eV was irradiated on a chip of a Si(l 11) wafer under a nitrogen gas pressure of 2 X 10(-4) Torr using a tungsten hot filament, the composition and the chemical bonding nature of the deposited materials were investigated by x-ray photoelectron spectroscopy (XPS). Although the deposited material using a filament power of 250 W showed almost the metallic gallium nature, the XPS spectra of the deposited Ga using the hot filament at a power of 300 W was very similar to that of an epitaxially grown GaN reference, indicating the possibility of the formation of GaN thin layer using the present method. Because the pure N-2 gas was used as the nitrogen source, no impurity fragments should be incorporated in the deposited materials. As a result, it is shown that the formation of hydrogen-free GaN layers is possible by Ga ion beam direct deposition under nitrogen atmosphere using N-2, gas and the hot filament. (C) 2004 American Vacuum Society.