Structure of Strip-like Magnetic Core of Thin Film Inductor.

In this paper, a new type of strip-like magnetic core is proposed. The structure of this core is prepared by separating the nearest-neighbor strip, Which is made of SiO2, by a gap (d), and then sputtering a magnetic film under an external field applied in a perpendicular to the exciting direction. The width of the strip lines(Ws)varied from 10∼1000μm. The arrangement of these high-density strip lines is confirmed by the domain structure and the frequency dependence of permeability. When the gap is greater than the thickness of the magnetic film, the magnetic domains are independent of each other, and the initial permeability is the same as that of the strip line film which is separated by space. When the strip width is decreased, the domain width decreases and the number of domains increases. The strip-like magnetic core is used in a thin film inductor. The inductance at 20 MHz and the maximum value of quality factor (Qmax) in the experimental inductor show maxima at about Ws=300∼500μm. This magnetic core is useful for increasing the inductance and quality factor of thin-film inductors.