Ferrite-Integrated On-Chip Inductors for RF ICs

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 $(L)$ for $\hbox{Y}_{2.8}\hbox{Bi}_{0.2}\hbox{Fe}_{5}\hbox{O}_{12}$ and $\hbox{Co}_{7}\hbox{ZrO}_{9}$ thin-film inductors, respectively, and 32%–55% improvement in quality factor $(Q)$ of $\hbox{Co}_{7}\hbox{ZrO}_{9}$ 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.