高電気抵抗軟磁性膜を用いた高周波インダクタ  [in Japanese] High-Frequency Inductor Using Highly Electrically Resistive Soft Magnetic Films  [in Japanese]

We investigated the use of planar-type inductors containing Co based soft magnetic films, which have highly electrical resistivity, as magnetic cores. Inductors were fabricated by using an RF magnetron sputtering method and a lift-off technique. Realizing smaller magnetostriction composition in a magnetic core is a major factor in obtaining a high quality factor (Q) in a inductor. Multilayering a zero magntostrictive Co-based film with SiO_2 film is an effective means of obtaining soft magnetic films at low substrate temperatures. A composite multilayered film consisting of thin and thick SiO_2 films proved to be an excellent soft magnetic film with very low eddy current loss and loss due to a resonance. The highest values of Q and the inductance of the inductor, which were obtained by using a composite multilayered film subjected to rotational field annealing, were 25.5 and 26nH at 180 MHz, respectively.