Improved Frequency Response of On-Chip Inductors With Patterned Magnetic Dots

Single-turn spiral inductors with magnetic material to enhance inductance are fabricated. Using double-layered Permalloy dots above and below the inductor metal, inductance improves and remains constant beyond 10 GHz with a $Q$ factor around 11 and a peak frequency around 9 GHz. By employing single-turn small-sized inductors, the self-resonance frequency of the inductors is shifted to very high frequencies. It is illustrated that the superior frequency response is mainly attributed to the significant reduction in mutual inductive coupling between a magnetic layer and inductor metal wires.