Microfabrication and characteristics of double-rectangular spiral type thin-film inductors with an upper NiFe magnetic core

Abstract

Simple, double-rectangular spiral-type thin-film inductors with an upper Ni 81 Fe 19 core for 5 MHz drive dc-dc converter application were investigated. Copper films 10-m-thick covered by a 3-m-thick NiFe film were used as the coils. The inductors fabricated in this study are 2.5 ϫ3.4-3.5ϫ5.5 mm 2 . The inductors developed, with a small size of 2.97ϫ3.1 mm 2 , exhibit L of 1.43 H, quality factor of 15.8, and resistance of 2.88 ⍀ at 5 MHz, and show results comparable to those reported in recent literature for similar inductors sandwiched by more complex magnetic core materials. An analysis of the experimental data suggests an equivalent circuit of the fabricated inductors. From the equivalent circuit analysis, C was shown to have a negligibly small effect over the frequency ranges used. The calculated data obtained from the equivalent circuit and the well-known equation of Q described the high-frequency data of the L, Q, and impedance of the inductors developed well.

Simulation of high frequency properties of planar magnetic inductors prepared by direct write techniques

“…The permalloy film was selected as the magnetic core material because of its high permeability at hf, high saturation magnetisation, high ferromagnetic resonance frequency and the fact that is known to be a well behaved material in the area of magnetic research. 4 Due to the skin effect of the internal conductor of coils in radio frequencies (RFs), highly conductive silver metals Ag, with the thickness range of 3-30 mm, were used as coils in order to decrease the metal loss of the microinductors. As shown in Fig.…”

“…in laptop computers, camcorders, cellular phones, etc. [1][2][3][4] Two major applications of planar magnetic inductors, which depend on the operating frequencies, include (i) operation in a few megahertz as integrated magnetic micropower converter devices 2,4 and (ii) operation in gigahertz as inductive components in microwave circuits as well as in signal processing circuits. [1][2][3] For the development of high performance, microfabricated magnetic inductors, however, the microelectromechanical systems (MEMS) [5][6][7][8] and silicon based photolithography techniques, [9][10][11] which are made up of complicated fabrication processes, have been required recently.…”

Application of ferrite layers in low‐profile OLED drivers

“…Alternatively, the double-coil inductor consists of a winding which is partitioned in two sub-coils. The double-coil inductor design is introduced in [15], where it was used to investigate amorphous ferrite films and it was used in [16][17][18] as a device that is based on rotation magnetisation process. More recently, the multi-coil winding designs with ferrite layers are used on-chip in a switching power converter [19].…”

In-plane Uniaxial Anisotropy and Magnetization Reversal Mechanism of FeCo Films by Strip Pattern

“…Soft magnetic materials are widely used in the modern electronic devices, e.g., audiovisual, house appliances, electro magnetic compatibility devices, and so on [1,2]. With the development of information technology, the demands on the density of information storage and speed of information transmission and conversion are increasingly high [3][4][5][6][7][8][9]. For the high-frequency applications of soft magnetic thin films, one need the magnetic thin films having a high saturation magnetization (4pM s ), a relatively large in-plane uniaxial anisotropy (IPUA) field (H k ) and a high electric resistivity in order to obtain a high ferromagnetic resonance frequency f FMR and a low eddy current loss [10][11][12][13][14][15][16][17].…”