Monolithic planar RF inductor and waveguide structures on siliconwith performance comparable to those in GaAs MMIC

摘要

The monolithic inductors and transmission lines on Si substratewith very high Q factor, low insertion loss, and high resonantfrequency, are achieved by using very thick polyimide (10 μm) asdielectric material, and thick Al (4 μm) metalization system. Thisstructure is made on the finished conventional standard two layermetalization BiCMOS wafer. For 10 nH inductor, 6 GHz resonant frequency,maximum Q factor of 5.5 at 1.2 GHz, and 1.2 dB insertion loss at 3 GHzare obtained, which are very comparable to those available in GaAs MMIC,These inductors can be used as RF choke as well as matching element.Transmission lines are also fabricated using this technology. TheS₂₁ of coplanar waveguide with 1 mm length is -0.2 dB at 4GHz, and that of microstrip line is -0.3 dB. It is expected that, usingthese passive elements, Si RF IC can be designed up to several GHz withperformance comparable to GaAs MMIC