The monograph is designed to illustrate the basics of dielectric barrier discharge plasma (DBD), deposition of hydrogenated carbon nitride (HCNx), its characterization and application toward biology. Chapter 1 deals with the dielectric barrier discharge apparatus and its basic functions. In chapter 2, the gas phase chemical reaction in CH4/N2 DBD plasma by quadrupole mass spectroscopy has been discussed. In Chapter 3, the variation of polarization (P) and the temperature (?T) at the electrode surfaces during the deposition of HCNx in CH4/N2 (1:2) DBD plasma has been considered. Chapter 4 deals with the study of role of nitrogen in chemical shift in HCNx film. In chapter 5, low dielectric property of Hydrogenated carbon nitride is investigated. In chapter 6, role of nitrogen in optical and electrical band gap of Hydrogenated carbon nitride is discussed. The shake up satellites peaks in x-ray photoelectron spectrum and chemical changes after annealing treatment on HCNx film have been considered in chapter 7. Cancer cells viability and cytotoxic effect of HCNx film has been considered in chapter 8. The last chapter deals with the DBD plasma treatment on E.coli bacteria.