To address the growing need for smaller integrated passive components, inductors were fabricated with magnetic material on silicon using a standard silicon processing tool set. CoZr based alloys were targeted due to their soft magnetic properties, high crystallization temperature and compatibility with fabrication facilities. The best results measured were from inductors which exhibited -60% increase in inductance for a single layer of 1.0μm of CoTaZr. Sandwiched inductors with 0.41μm of CoTaZr above and below the planar spiral show enhancement of -100%. Inductors with CoNbZr were also fabricated, however, the magnetic properties degraded during high temperature processing. Finally, the effective permeability of the CoTaZr inductors was estimated to be-85-150 depending on the device geometry.
This paper shows a method for the numerical quality factor optimization of a high frequency inductor based on a genetic algorithm. This is pointed out by an example of a trench-type or I-inductor. A comparison between different design approaches will show the advantages of themselves. First results for a further application as a micro transformer of such a device are described.
Characteristics of a monolithically integrated microstrip with a thin-film Ni80Fe20 ferromagnetic core are studied. Ni80Fe20 film was electroplated on Si substrate in an external dc magnetic field (80 m T) along the strip line direction. The structure exhibits a peak attenuation of-19dB/cm at 2.8 GHz, a large wavelength reduction 60% at 1GHz, and over 100% enhancement of quality factor compared to the control devices.
In this paper, a model describing frequency dependentcharacteristics of a sandwiched microsrtrip with aferromagnetic core, is developed. The approach is basedon the assumption, that the characteristics of a sandwichedmicrostrip are mostly determined by a quasi-TEM mode. Frequency profiles of the inductance and resistance perunit length, attenuation, and wave-length are calculated.The increase of the inductance per unit length and thewavelength shortening are obtained due to the presence ofa Ni Fe ferromagnetic core. The results of modeling arediscussed and compared with experiments
RF hybrid microstrip line with a Polyimide (1 μm)/CoZrNb (1 μm)/Polyimide (1 μm) sandwich was fabricatedand characterized. The hybrid microstrip line exhibited alarge effect of the wavelength-shortening, and the largesignal-decay at around or over the intrinsic ferromagneticresonance (FMR) frequency. To discuss the effect of thepower dissipation on the signal transmission wasdiscussed on the basis of the experimental results andpower loss estimation using the electromagnetic fieldanalysis with taking the FMR into account. The insertionloss around or over the intrinsic FMR point was not onlyowing to the FMR absorption, but also owing to the eddycurrent enhancement by skin effect anomaly by the FMR.
Soft ferromagnetic zero-magnetostrictive Co Nb Zr thin films have been dynamically deposited by dc planar magnetron sputtering onto continuously transported substrates. No magnetic field has been applied to the films during deposition. The films reveal a well-defined in plane uniaxial anisotropy with an easy axis aligned along the direction of substrate motion. As a result, an anisotropy field of 75 Oe and a ferromagnetic resonance frequency of 2.6 GHz have been measured. The study of the relationship between magnetic properties and film thickness points out a critical thickness around 0.3 μm, above which the films exhibit a stripe-domain-like behavior which is detrimental for the high frequency use. The thermal stability of the films is found to be usual as regular amorphous core materials (stable up to 300°C). Additionally, it is shown that the films do not suffer from rotatable magnetic anisotropy usually observed inconventional statically deposited films under magneticfield. Finally, a different origin of the magnetic anisotropyis suggested in dynamically deposited films.
(CoFeB)-(Si01.9) and CoFeB films were fabricated by synchronous triple RF magnetron sputtering with rotating a cylindrical electrode. Three types films for RF application in the range over 1 GHz were obtained, and these permeability characteristics and micro-structures were investigated. The as-deposited films exhibited large anisotropy field Hκ in the range from 40 to 550 Oe, and exhibited highferromagnetic resonance (FMR) frequencies of 1.6-6.0 GHz in permeability characterisrtics. The films exhibited amorphous like or hetero-amorphous structures, which led to good soft magnetic properties with electrical resistivity ρ of 100-100, 000 μΩcm and saturation magnetization 4πMs, of 6.5-20kG. It was found that the obtained larger Hκ was effective to attain the higher frequency characteristics with the lower losses for RF inductor cores.