Xenon irradiation ofNi3N/Sibilayers: Surface roughening and interface mixing and reactions

The irradiation effects in ${\mathrm{Ni}}_3\mathrm{N}/\mathrm{Si}$ bilayers induced by 100–700 keV Xe ions at fluences up to $4\times {10}^{16}$ $\mathrm{ions}/{\mathrm{cm}}^2$ were investigated at 80 K and room temperature. The element depth profiles were measured via Rutherford backscattering (Ni,Si) and resonant nuclear reaction (N) analysis, the phase formation at the interface via x-ray diffraction, and the surface roughness by atomic force microscopy. The observed dissociation and preferential sputtering of ${\mathrm{Ni}}_3\mathrm{N}$ followed by nitrogen out-diffusion were related to the small binding energy of this compound. Mixing at the ${\mathrm{Ni}}_3\mathrm{N}/\mathrm{Si}$ interface occurs via a combination of diffusion and reaction controlled transport processes and the interface broadening varies in second order with the ion fluence. At higher ion fluences, the formation of ${\mathrm{NiSi}}_2$ and ${\mathrm{Si}}_3{\mathrm{N}}_4$ phases at the interface was found.