Fully integrated ferrite-based inductors for RF ICs

Ferrite thin-film RF integrated inductors using IC compatible processes are proposed firstly. Ferrites (Co-based, CoFe-based, MnZn-based, NiZn-based and garnet) for RF integrated inductors are investigated, and CoZrO shows the suitable high-frequency performance for RF applications. Various inductors with different kinds of ferrite thin-films have been fabricated using fully integrated processes. A typical inductor sample with CoZrO thin-film is presented. The L and Q values of the sample are 2.05 nH and 20.5 at 2 GHz, respectively. The inductance is raised by 17% and the quality factor is raised by 41%, compared with the inductor which does not include a ferrite thin-film. With the improvement of L and Q, the size of ferrite thin-film inductors can be reduced significantly.