XPS studies on silicon carbonitride films prepared by sequential implantation of nitrogen and carbon into silicon

Abstract

Silicon carbonitride films are synthesized by sequential implantation of nitrogen and carbon into silicon. The evolution of the chemical bonding states between silicon, nitrogen and carbon is investigated as a function of implantation sequence and ion dose using X-ray photoelectron spectroscopy. Nitrogen ion implantation into silicon saturates upon the formation of a stoichiometric silicon nitride film. Successive implantation of carbon into this film leads to the formation of a complex of silicon carbonitride and pure carbon. The formation of CN bond is insignificant. Carbon ion implantation into silicon leads to a continuous increase in carbon concentration till the formation of a nearly pure carbon film at the surface. Successive implantation of nitrogen into this film first forms a film dominated by CC and CN bonds. With increase in nitrogen ion dose, it evolves into a silicon nitride film containing a small fraction of CC, CN and CSi bonds. The formation of CN bond is due to the existence of large amount of pure carbon.