Experimental investigation of multi-path and metal-stacking structure for 8-shape on-chip inductors on standard CMOS

An experimental investigation reports on the effectiveness of multi-path and metal-stacking structure in regard to quality factor improvement for on-chip 8-shaped inductors on standard CMOS process. It is found that the multi-path structure has little positive impact on the 8-shaped inductors, while the metal-stacking structure improves quality factor significantly. For a 0.5 nH 8-shaped inductor with top two layers metal-stacking, a good differential quality factor of ∼15 at 10 GHz and ∼17 at 13 GHz is obtained, which makes the inductor suitable for the design of low-cost and interference-immune over-10 GHz radio-frequency and high-speed integrated circuits.