Design of Novel High-<inline-formula> <tex-math notation="TeX">\(Q\) </tex-math></inline-formula> Multipath Parallel-Stacked Inductor

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

“…The effectiveness of multi-path and metal-stacking structure is explicitly depicted. First, as opposed to what were reported in previous papers [3,4], the multi-path scheme shows little positive impact on the improvement of quality factor at both lower frequencies and above 10 GHz. The possible reasons lie in the metal thickness and the multi-path structure itself.…”

“…From above, the positive aspect of applying the multi-path structure is reduced skin effect, while the negative aspects are reduced effective width and additional proximity effect between paths, which makes the multi-path inductors experience much more proximity effects than the single-path ones. In our cases, the thickness of top metal is only 0.86 μm, as compared with ∼3 μm in [3,4]. Smaller thickness will definitely show less skin effect.…”

“…The alternative way is to explore the structure optimisation methods to increase the quality factor of on-chip inductors on standard process. In previous works, the multi-path [3,4] and metal-stacking [5,6] structure had been investigated based-on traditional inductors, whereas this Letter will discuss the effectiveness of these two methods on 8-shaped inductors on standard process.…”

“…Multi-path and metal-stacking structure: One of the potential ways to reduce current crowding effect is to use multi-path structure [3,4]. For a single metal line, the cross-sectional current density exhibits lateral non-uniform distribution and concentrates at the two edges.…”

“…This length imbalance may degrade the effectiveness of the multi-path scheme. In [3,4], the crossover structures are designed to deal with this issue. While for 8-shaped inductors, it can be seen from Fig.…”