Microstructural characterisation of metal ion implanted silicon nitride

The microstructure of silicon nitride after metal ion implantation at different dosages has been studied. A metal vapour vacuum arc (MEVVA) ion source was employed to implant Ni, Ti and Ni+Ti ions into silicon nitride. Characterisation of the implanted surfaces was carried out by Rutherford backscattering spectrometry (RBS) and cross-sectional transmission electron microscopy (XTEM), in conjunction with nano-beam electron diffraction (NBED) analysis. It was established that the thickness of the implanted layer was in the range of 210–280 nm, depending on implantation species and energy. Titanium or nickel implantation under present conditions resulted in the formation of an amorphous layer and precipitation of titanium or nickel nitrides. However, when Ti and Ni were both implanted successively at half the total dose, the modified layer was fully amorphised with no evidence of precipitation.