Composition change in magnetron-sputtered Fe-Zr-N film with erosion of Fe-Zr alloy target

The composition of magnetron-sputtered Fe-Zr-N films is found to change with the erosion of the high-permeability Fe-Zr alloy target. Zr is preferentially sputtered parallel to the target surface, and this tendency is more pronounced as erosion increases, Incident ion energy decreases with erosion because the leakage magnetic flux intensity increases, and the plasma density increases as a result of enhanced ionization frequency. This composition change has been attributed to a reflective collision process becoming dominant as the incident ion energy decreases with increasing erosion. A novel mosaic-type target, consisting of both alloy and single-element phases, has been developed, and the composition change is successfully suppressed and compositional uniformity is markedly improved.