PLANAR INDUCTORS ON SILICON FOR INTEGRATED RF CIRCUITS

We have studied the fabrication and modelling of integrated planar ind uctors on silicon made by using a standard 0.8 mu m BiCMOS process. In order to aid the design of circuits including integrated inductors we have developed and tested a semiempirical equivalent circuit model fo r the planar inductors. The model, which has been implemented in the c ircuit simulator APLAC, shows good agreement with the measured inducto r values, quality factors and S-parameters. Although the measured Q-va lues are below 10 in the GHz frequency range, the integrated inductors can be utilized in many RF IC applications. As a first demonstration for this we have successfully applied an integrated inductor to a low voltage monolithic voltage-controlled oscillator circuit at 1.8 GHz.