Inductance and Q‐Factor of Micromagnetic Inductor Are Enhanced by FeCoB Films with Self‐Bias

Abstract

As technology progresses, the operational frequencies of electronic devices have migrated into the GHz range. As an important electronic device, the compatibility of the preparation process of inductors with integrated circuits also needs to be improved. Currently, most commercial inductors are constructed from ferrite materials, making them challenging to integrate with integrated circuits. Herein, FeCoB films with a self‐biased ferromagnetic frequency up to 21 GHz are deposited on Si substrates using the compositional gradient sputtering method as a magnetic underlayer. A reasonable inductance structure is designed using HFSS simulation software. A series of planar spiral inductors with various turns are fabricated by photolithographic micromachining on the FeCoB films with a polyimide insertion between them. The preparation process is completely based on semiconductor technology and has good compatibility with integrated circuits. The results show that the inductance L and quality factor Q are greatly improved by the introduction of high‐frequency FeCoB film. The inductance is improved by 71% and the quality factor is improved by 166%. This clearly demonstrates that FeCoB thin films are highly suitable for use as inductor cores and can be seamlessly integrated with integrated circuits, offering excellent prospects for use in high‐frequency integrated circuits.