IC compatible planar inductors on silicon

The authors present a systematic study of the modelling, design, and fabric ation of planar spiral inductors implemented in a high speed 0.8 mu m BICMO S technology, and characterised for use in portable VHF applications. Both a fully empirical distributed equivalent circuit model and a more accurate semiempirical model for the integrated inductors have been developed and te sted. The latter broadband model is scalable and thus applicable also for i nductor design. The IC compatible inductors on silicon were fabricated usin g a process featuring oxide isolation and two layers of metal. For comparis on, some test inductors were also fabricated using nonstandard techniques s uch as 4 mu m thick oxides and 4 mu m thick Al metallisation. The rectangul ar spiral inductors showed larger Q values than the octagonal ones. The lar gest Q value measured was 16. As expected, this value was obtained by using a combination of thick oxide and thick metallisation. The results are enco uraging for the use of integrated inductors in silicon RF ICs in the GHz fr equency range.