Acceleration voltages which ranged from 200 to 2000V were used to implant Fe, Fe-9at%Ti and Fe-19at%Ti evaporated thin films with N at temperatures which ranged from 270 to 400C. When the substrates were maintained at 300 to 400C, redistribution which was due to diffusion of the implanted N was observed; even when energies as low as 1keV were used. Although the N atoms which were implanted into the Fe thin films had a non-uniform distribution, almost homogeneous deep distributions of the N atoms were obtained in the case of Fe-9at%Ti films. This was attributed to a preferential binding between the Ti and N atoms. However, it was recognized that the depth profiles of the N atoms which were implanted into Fe-19at%Ti films became shallower than those in Fe-9at%Ti films. The diffusive movement of implanted atoms, which occurred at a lower temperature than the ion-nitriding treatment, was attributed to the avoidance of nitride formation at the substrate surface by forcing the direct implantation of N atoms into surface layers.

S.Ohtani, M.Watanabe, N.Iwamoto: Journal of the Japan Institute of Metals, 1995, 59[8], 851-6