Modeling, design, fabrication and characterization of miniaturized, high-current handling and high-efficiency inductors

Abstract

Analytical models were developed to design magnetic materials with desired permeability and frequency stability. Two loss mechanisms, eddy current loss and ferromagnetic resonance (FMR) loss, were included in the models to capture behaviors of magnetic materials at high frequency. Based on the models, magnetic materials were designed to have 2D flake shape for both high permeability and high-frequency stability. The accuracy of developed models were proofed by the good correlation between calculated and measured permeability data. By incorporating the designed magnetic flakes as the cores, two types of magnetic-core inductor, spiral inductors and solenoid inductors, were modeled and designed by using finite element models (FEMs) to achieve high current-handling. Furthermore, innovative substrate-compatible processes were developed to fabricate the designed magnetic-core inductors. One process named as core-less process was developed to fabricate the spiral inductors. Another process named as cavity-embedding process was developed to fabricate the solenoid inductors. Electrical characterizations were performed to measure the frequency-dependent and current-dependent inductance of fabricated inductors. A good correlation between measurement and simulation was observed, indicating the accuracy of inductor FEMs.