Performance Improvement of On-Chip Solenoid Type Power Inductors

An on-chip solenoid type power inductor utilizing double layer laminated thin film cores with nanogranular magnetic materials of Fe-Co-Ti-O is presented. Increments of 23% in inductance up to 500 MHz and 21% of quality factor at 100 MHz are obtained compared with usual solenoid inductor with single layer laminated thin film core. And the L improvement is proved by simulation to be bigger if the magnetic films have a higher permeability or thicker thickness. The influence of copper winding thickness on DC performance is also analyzed. The results show that increasing the thickness of winding coils within the process technology ability can effectively improve the performance of the proposed inductor at low frequency. The coupling coefficient achieves 0.85 and can be easily adjusted by changing the turn number of parallel windings to easily meet the requirement of circuit design.