A low-temperature silicon nitride (SiNx:H) film-deposition technique that utilizes ultraviolet (UV)-irradiated ammonia (NH3) as the reactant gas and nonirradiated disilane (Si2H6) as the precursor gas was investigated. The UV light was only used to generate active species from NH3, not to irradiate the substrate. To determine the effect of the active species on the deposition process, SiNx:H films were deposited via chemical vapor deposition and their refractive index and composition ratio were evaluated. The results demonstrate that the highly reactive species generated from UV-light-irradiated NH3 enabled the deposition of nitrogen-containing films between 30°C and 450°C. N/Si ratio and refractive index of approximately 1.33 and 1.9–2.0, were obtained for a SiNx:H film deposited at 350°C and 450°C, respectively.