Stacked-spiral RF inductors with vertical nano-particle-magnetic-medium

A new concept of stacked-spiral inductor with vertical near-closed-circuit nano-particle-magnetic-core in CMOS is reported. Prototypes, fabricated in a 6-Al-metal CMOS backend process using ferrite nano-particles, show a high inductance-density of 825nH/mm 2 in multi-GHz, which is promising for making super compact inductors in RF SoC.