Tantalum nitride (TaN) films are deposited on silicon substrates by radio frequency (RF) reactive sputtering of Ta in N-2/Ar gas mixtures at a bias of 0 V. The deposition rate, chemical composition, and crystalline microstructure are investigated by cross-sectional transmission electron microscopy (XTEM), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), X-ray diffraction (XRD), and atomic force microscopy (AFM), respectively. According to those results, the deposition rate, film composition, and microstructure correlate with the N-2/Ar flow ratio. In addition, the deposition mechanism which controls the film characteristics is presented as well.