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.