Improved High Frequency Response and Quality Factor of On-Chip Ferromagnetic Thin Film Inductors by Laminating and Patterning Co-Zr-Ta-B Films

Abstract

In this work, we report the improvement of high frequency response and quality factor of on-chip inductors by integrating ferromagnetic thin films (Co-Zr-Ta-B) including two different combinations of laminations and 500 nm thick non-laminated film. Up to 4.2X increase in inductance and 5X increase in quality factor (Q) was obtained from 4-turn spiral inductors incorporated with 50 nm by 10 laminated films with a peak Q at 500 MHz. Effects of patterning magnetic film have also been investigated by changing magnetic thin film aspect ratio. It was demonstrated that the peak Q can be pushed towards using higher frequencies as high as 1 GHz by a combination of patterning magnetic films into fine bars and laminations.