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MEMS based fabrication of high-frequency integrated inductors on Ni–Cu–Zn ferrite substrates
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Accepted Version
Date
2015-12-29
Authors
Anthony, Ricky
Wang, Ningning
Casey, Declan P.
Ó Mathúna, S. Cian
Rohan, James F.
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Published Version
Abstract
A surface micro-machining process is described to realize planar inductors on ferrite (Ni0.49Zn0.33Cu0.18 Fe2O4) for high-frequency applications (<30 MHz). The highly resistive nature (~108 Ω m) of the Ni–Cu–Zn substrate allows direct conductor patterning by electroplating of Cu windings through a photoresist mold on a sputtered seed layer and eliminates the need for a dielectric layer to isolate the windings from the bottom magnetic core. Measured inductances~367 nH (DC resistance~1.16 Ω and Q-value>14 at 30 MHz) and ~244 nH (DC resistance~0.86 Ω and Q-value~18 at 30 MHz) at 1 MHz for elongated racetrack (10.75 nH/mm2) and racetrack inductors (12.5 nH/mm2), respectively show good agreement with simulated finite element method analysis. This device can be integrated with power management ICs PMICs for cost-effective, high-performance realization of power-supply in package (PSiP) or on-chip (PSoC). This simple process lays the foundation for fabricating closed core ferrite nano-crystalline core micro-inductors.
Description
Keywords
Ferrite , Micro-fabrication , Micro-Inductors , Integrated magnetics , DC–DC converters
Citation
Anthony, R., Wang, N., Casey, D. P., Ó Mathúna, C. and Rohan, J. F. (2016) 'MEMS based fabrication of high-frequency integrated inductors on Ni–Cu–Zn ferrite substrates', Journal of Magnetism and Magnetic Materials, 406, pp. 89-94. doi:10.1016/j.jmmm.2015.12.099