MICROHARDNESS AND MICROSTRUCTURE OF ION-BEAM-SPUTTERED, NITROGEN-DOPED NIFE FILMS

The microhardness depth profiles of ion-beam-sputtered NiFe 0.5 μm thick films with various contents of nitrogen were measured by using a newly designed microindenter. The concentration of the nitrogen was controlled by the nitrogen partial pressure during the deposition. It was found that the microhardness of NiFe films can be increased up to 20% as the nitrogen partial pressure increases up to 8×10-5 Torr, although the Young's moduli are not affected significantly. The microstructures of the pure NiFe and N2-doped NiFe films were also studied by using plane-view and cross-section transmission electron microscopy. Structural modification because of the entrapment of nitrogen was observed.