Cost Effective Parallel-branch Spiral Inductor with Enhanced Quality Factor and Resonance Frequency

In this paper, we present a cost effective parallel-branch spiral inductor with enhanced quality factor and resonance frequency. This structure is designed to improve the quality factor, but different from other fully stacked spiral inductors. The parallel-branch effect is increased by overlapping the first metal below the second metal with same direction. Measurement result shows an increased quality factor of 12% improvement. Also, we show an octagonal parallel-branch inductor which reduces parasitic capacitances for higher frequency applications