Silicon nitride and oxynitride films prepared by ion beam reactive sputtering

The composition of particles sputtered from a silicon target during bombardment by nitrogen and oxygen ions was measured. Elementary processes on both the substrate and the target were examined. A model of silicon nitride film formation was proposed, in which the main idea is the interaction of silicon on the substrate with the atomic nitrogen sputtered from the target. The dependence of the film properties on the oxygen concentration in N₂O₂ mixtures was investigated. The relationship between the nitrogen and silicon concentrations in silicon nitride films, the nitrogen ion beam incidence angle and the ejection angle of the sputtered particles was revealed experimentally. In the proposed model this relationship is interpreted as a result of the difference between the angular distribution of silicon and nitrogen atoms sputtered from the target.