Experimental comparison of substrate structures for inductors and transformers

An experimental comparison of the substrate structures for silicon inductive devices is proposed. On-wafer measurements for both inductors and stacked transformers revealed that better performance is achieved by exploiting a n⁺-doped buried layer as a patterned ground shield. The proposed solution increases inductor quality factor and allows a wide operative bandwidth for transformers to be achieved, as well. Moreover, owing to a well-defined RF ground reference, cross-talk phenomena are inherently reduced. Finally, the buried layer patterned ground shield highly simplifies substrate modeling and allows accurate electromagnetic simulations to be easily carried out.