Composition and conduction properties of silicon nitrides deposited by plasma-enhanced ultra-high-vacuum chemical vapour deposition

A Some fundamental properties of silicon nitride deposition by electron cyclotron resonance plasma-enhanced chemical vapour deposition have been studied. Silane and nitrogen were used to deposit the layers used for the study. The deposition temperature was maintained above 500°C in order to ensure that the hydrogen content of the film was marginally small, which was confirmed by X-ray photoelectron spectroscopy measurement. It was observed that, in order to deposit stoichiometric Si₃N₄ films, the flux of the volatile component nitrogen must be increased until the [N₂]/[SiH₄] ratio is well above 25. The leakage currents in both silicon-rich and stoichiometric films were investigated. The measured refractive index of the films was used to highlight the role of various species during the deposition of the films.