Ferrite-Integrated On-Chip Inductors for RF ICs

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This letter reports the design and fabrication of on-chip radio-frequency (RF) inductors with integrated-ferrite thin films, which show substantial improvement over air-cored inductors, e.g., 19%–38% and 17%–28% increase in inductance <formula formulatype="inline"><tex>$(L)$</tex></formula> for <formula formulatype="inline"><tex>Y2.8Bi0.2Fe₅O₁₂</tex></formula> and <formula formulatype="inline"><tex>Co₇ZrO₉</tex></formula> thin-film inductors, respectively, and 32%–55% improvement in quality factor <formula formulatype="inline"><tex>$(Q)$</tex></formula> of <formula formulatype="inline"><tex>Co₇ZrO₉</tex></formula> sample, which are all measured across 0.1–9 GHz. It demonstrates the feasibility for making the ferrite-integrated high-performance compact on-chip inductors for RF ICs. </para>