Multilevel-spiral inductors using VLSI interconnect technology

A multilevel-spiral (MLS) inductor structure for implementation in VLSI interconnect technology is presented, Inductances of 8.8 and 32 nH and maximum quality-factors (Q) of similar to 6.8 and 3.0, respectively, are achieved in a four-level metal BiCMOS technology, with four turns at each of the two or four stacked spiral coils and with an area of 226 x 226 mu m(2), The comparison of the MLS inductors to different single-level-spiral (SLS) control de,ices shows that a MLS inductor pro,ides the same inductance at similar to 50% de resistance, but the maximum Q is typically measured at a lower frequency and the self-resonance frequency is reduced due to a high inter-wire capacitance.