The effects of substrate resistivity on RF component and circuit performance

The benefits of using high-resistivity substrates for RF CMOS applications are experimentally quantified. The quality factors of spiral inductors with a patterned ground shield, varactors, and transistors have been measured on both p/sup +/ (with epi) and p/sup -/ substrates, and in each case, Q is higher on p/sup $/substrates. A 5.35-GHz VCO on a p-substrate has an 8 dB lower phase noise than that on a p/sup +/ substrate, while a 7-GHz LNA on a p/sup -/ substrate has a 6 dB higher gain and /spl sim/2.5 dB lower noise figure than that on a p/sup +/ substrate.