SPUTTER ETCHING STUDIES OF FE-NI AND FE-PD FILMS

Sputtering studies of Fe//1// minus //x-Ni//x (x equals 0. 05 to 0. 95) films were made and compared with those of Fe//1// minus //x-Pd//x (x equals 0. 06 to 0. 7) films. Plots of steady-state AES and ESCA signal intensity ratios versus bulk composition ratios for the Fe-Pd system gave two straight lines intersecting near x equals 0. 38, where a bcc to fcc phase transition occurs. Similar plots for the Fe-Ni system showed a single straight line across the whole composition range although a similar phase transition occurs at x similar 0. 4. Values of slopes obtained from normalized AES and ESCA data were similar for the Fe-Ni but differed by a factor of 3 for the Fe-Pd system. Since ESCA has a larger sampling depth than AES for both alloy systems, these differences are attributed to the presence of a significant altered layer on the sputtered Fe-Pd surface, which is absent on sputtered surfaces of Fe-Ni films. This result is compared to the different diffusion rates of these two systems: (1) Depth profiles for air-exposed and deliberately oxidized (160 degree -250 degree C) films indicated that diffusion is much faster in the Fe-Ni than the Fe-Pd systems, and (2) direct measurement of interdiffusion in Fe-Ni and Fe-Pd couples demonstrated much faster interdiffusion in the Fe-Ni system.