The properties of silicon nitride, oxynitride, and oxide films formed by the pyrolysis of various mixtures of , , and are presented. The variation in physical, optical, and electrical properties of this oxynitride series is examined. The electrical and passivation properties of these films on Si are examined and compared with oxides. These electrical data describe the general characteristics of nitride and oxynitride on top of Si and over thin (∼300Aå) and thick (∼1000Aå) thermal oxide films.