Analysis of Silicon Nitride Layers on Silicon by Backscattering and Channeling Effect Measurements

Backscattering and channeling effect measurements with MeV 4He ions were used to determine the depth dependence of the composition of amorphous silicon nitride layers on single-crystal silicon. The composition was stoichiometric over the entire layer for high ratios of NH3 to SiH4 used in the deposition reaction at 850°C. For lower ratios, a silicon excess was found, and in extreme cases, the silicon excess was located predominantly near the interface.