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⁺ (with epi) and p ^- substrates, and in each case, Q is higher on p^$substrates. A 5.35-GHz VCO on a p-substrate has an 8 dB lower phase noise than that on a p⁺ substrate, while a 7-GHz LNA on a p^- substrate has a 6 dB higher gain and ~2.5 dB lower noise figure than that on a p⁺ substrate