This article provides an overview of the state-of-the-art chemistry and processing technologies for silicon nitride and silicon nitride-rich films, i.e., silicon nitride with C inclusion, both in hydrogenated (SiNx:H and SiNx:H(C)) and non-hydrogenated (SiNx and SiNx(C)) forms. The emphasis is on emerging trends and innovations in these SiNx material system technologies, with focus on Si and N source chemistries and thin film growth processes, including their primary effects on resulting film properties. It also illustrates that SiNx and its SiNx(C) derivative are the focus of an ever-growing research and manufacturing interest and that their potential usages are expanding into new technological areas.