The ability to produce high quality films in an electron cyclotron resonance reactor is dependent on the gas distribution system. In an effort to understand gas distribution effects, a variety of gas ring injection systems were implemented during silicon nitride growth. Film refractive index, uniformity, and stress were used to gauge each gas distribution system. As a result, we have demonstrated that evenly distributed gas injection systems are the most desirable producing uniform films. Film thickness uniformity was significantly influenced by the design of the gas ring as well as the gas flow. Theoretical models supported the observed results and identified desirable properties for gas ring distribution systems.