This invention relates to a process for the production of a solid thin film containing silicon and nitrogen on a substrate, said film having an aggregate low concentration of inorganic carbon and oxygen of less than about 51 atom percent, which process comprises:(A) contacting the substrate with a gaseous mixture itself comprising:(i) a volatile cyclic organic silicon-nitrogen source, and(ii) a reactant independently selected from hydrogen or a hydrogen-nitrogen source, under plasma enhanced chemical vapor deposition conditions of pressure lower than 10 Torr and temperature greater than ambient temperature for a time sufficient to produce a silicon nitride thin film. In another aspect, the invention relates to the silicon-nitride thin film coated article or substrate produced by the process of the present invention. Preferred process conditions evaluates include the RF of 13.56 MHz, 20-80 W Power, power density 0.37 watts/cm.sup.2 to 1.5 watts/cm.sup.2 and a ratio of the silicon-nitrogen source and the hydrogen nitrogen source of between about 0.1/19.9 and 0.6/19.4 percent by volume. When ammonia is used, the aggregate concentration of carbon and oxygen is less than 20 atom percent, preferably less than 10 atomic percent.