Non-lithographic and scalable fabrication of one-turn-like inductor having laminated NiFe core for power converters operating at high frequency

Abstract

We fabricated one-turn-like wire inductor via electrodepositing magnetic core materials, NiFe, on the surface of cylindrical copper wires. The current was applied to flow through a copper wire which generated circumferential magnetic flux around the wire. Control of core thickness and wire lengths showed tunability of inductance values. Compared to an air-core wire inductor (no magnetic core on a wire), 50 μm thick NiFe electroplated wire inductor had 144 times higher inductance values. We also achieved sequential electroplating of NiFe and interlamination layer, polypyrrole, on wire surfaces. Laminated cores showed higher retention of inductance compared to a single layer NiFe core, demonstrating wire inductor’s applicability in high frequency applications. Our one-turn-like wire inductors provide an effective strategy to fabricate micro-inductors in a simple and scalable manner to be integrated for Power system-in-package.