Takayuki Kusumi

Ferromagnetic RF integrated inductor with closed magnetic circuit structure

Closed magnetic circuit type ferromagnetic RF integrated inductors have been fabricated based on MEMS-like micro fabrication techniques. The taper etching process greatly helped to endure sufficient magnetic flux flow at the edge of the top and bottom magnetic layers. Air cores and three different sandwich type ferromagnetic inductos are also microfabricated. Measured results exhibited the quality factor Q=12, being highest among the published data of ferromagnetic RF integrated inductor at 1 GHz. Index Terms — integrated inductor, magnetic film, electromagnetic field simulation, quality factor.

Closed magnetic circuit structure for RF integrated spiral inductor

This paper studies the microfabrication process and the experimental demonstration of a closed magnetic circuit type GHz-drive integrated spiral inductors, consisting of a stack of 0.2-/spl mu/m-thick RF-sputter deposited CoNbZr, RF-sputter deposited SiO/sub 3/, 3-/spl mu/m-thick electrodeposited Cu coil, SiO/sub 3/ with surface planarization, and 0.2-/spl mu/m-thick RF-sputter deposited CoNbZr. Main idea is to establish the fabrication process of such a sophisticated microstructure and to demonstrate as high quality factor as possible for the possible practical near-future applications. The structure of the closed magnetic circuit type inductor discussed in this paper.