Magnetic-Particle-Composite-Medium-Filled Stacked-Spiral Inductors for Radio-Frequency CMOS Applications

Magnetic-particle-composite-medium-filled stacked-spiral inductors for rf complementary metal oxide semiconductor (CMOS) applications in GHz are demonstrated. The new inductor features a nearly closed magnetic circuit loop, an optimized high-permeability and low-loss sub-1 μm magnetic particles' composite core, and a developed 0.18-μm CMOS-compatible device fabrication process. An equivalent circuit model with structural amplifying factors is proposed and modeled. The prototype of the 6-level stacked inductor with Co₂Z magnetic-particles-composite-medium filling increases the inductance L by 50%, and quality factor Q by 37% at frequencies as high as 1 GHz, with high inductance density as 825 nH/mm² and a reduced size area by 80% compared to the planar spiral inductor.