Characteristics of film type inductors using a FeZrBAg magnetic material

Two types of double rectangular spiral thin-film inductors with a multi-lay er structure of magnetic film/conduction film/magnetic film were fabricated using a Fe86.7Zr3.3B4Ag6 thin film with high permeability and resistance, in which easy axis of magnetization of the thin-film was perpendicular or p arallel to the current direction. The dependence of inductance and resonanc e frequency on the inductor type indicated that the perpendicular geometry inductor has higher inductance than the parallel geometry one, because spin s of magnetic film align more easily along the field direction due to highe r field intensity in the perpendicular geometry. However, the increase of t he inductance, resulted in the decrease of resonance frequency. Then the ef fects of permeability of the magnetic film on inductance and resistance of the perpendicular geometry inductor were investigated. The permeability was controlled by annealing the film at different temperatures. With increasin g the permeability, the inductance increased, but the resistance also incre ased due to the increase in magnetic core loss. As the resonance frequency was higher in air-core inductor than in magnetic thin-film core inductor, i t is suggested to increase the resonance frequency which is characteristic of the air-core inductor rather than magnetic properties of the magnetic th in-film should be enhanced. (C) 2001 Elsevier Science B.V. All rights reser ved.