Effect of Bias Voltage and Deposition Rate on the Structure and Coercivity of NiFe Films

The effect of the bias voltage U b and the deposition rate v on the structure, grain size D , and coercivity H c of NiFe films with a thickness d from 30 to 980 nm, grown on Si/SiO 2 substrates by DC magnetron sputtering, has been studied. In the case of U b = 0, a decrease in v from values v ≈ 27 to ≈7 nm/min is accompanied by an increase in the values of the critical film thickness d cr from d cr ≈ 220 nm to d cr ≈ 270 nm. In this case, H c in films with d < d cr is characterized by the dependence H c D 6 and varies from 1 to 20 Oe. For U b = –100 V, the effect of the deposition rate on the coercivity is much more noticeable. At v = 7 and 14 nm/min, the films exhibit soft magnetic properties ( H c ≈ 0.15–1.4 Oe) and the absence of d cr for the entire range of studied thicknesses. The films obtained at v = 21 and 27 nm/min pass into the “supercritical” state at d ≥ d cr ≈ 520 nm, and in the range d < d cr they are characterized by the dependence H c D 3 and an increase in the coercivity from 0.35 to 10 Oe.