Development of soft magnetic thin films for GHz applications

We recently fabricated as-deposited Fe-Co-Ni-B soft magnetic thin films by RF magnetron sputtering which have 4/spl pi/M/sub s/ of 21.5 kG, coercivity (H/sub c/) of 0.9 Oe, and the linear effective permeability of about 600 up to 1 GHz. Furthermore, a more effective method for increasing H/sub k/, i.e. an oblique deposition method, was suggested. Therefore, we have investigated the effects of the new, method on high frequency characteristics of Fe-Co-Ni-B soft magnetic thin films by the analysis of magnetic properties and microstructures. The soft magnetic properties and high frequency characteristics of single layer FeCoNiB thin films can be controlled by the oblique deposition method.