MEMS based fabrication of high-frequency integrated inductors on Ni–Cu–Zn ferrite substrates

A surface micro-machining process is described to realize planar inductors on ferrite (Ni0.49Zn0.33Cu0.18 Fe2O4) for high-frequency applications (14 at 30MHz) and ~244nH (DC resistance~0.86Ω and Q-value~18 at 30MHz) at 1MHz for elongated racetrack (10.75nH/mm2) and racetrack inductors (12.5nH/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. Material Characterization of Ni–Cu–Zn ferrite substrate and process developed for on-ferrite integrated micro-inductor fabrication. [Display omitted] •High-frequency microinductors have been fabricated on Ni-Cu-Zn substrates.•High-resistive ferrite substrates assist direct conductor patterning on the surface.•Uniform inductances ~365 nH over 30MHz frequency have been achieved.•High Q-values (>18 at 30MHz) attained are applicable for high-frequency DC–DC conversion applications.•The described process lays the foundation for fabricating closed core ferrite nano-crystalline core.