Characterization and modeling of enhanced voltage RF MESFETs on 45nm CMOS for RF applications

Enhanced voltage silicon metal-semiconductor-field-effect-transistors (MESFETs) have been fabricated on a 45 nm SOI CMOS technology with no process changes. MESFETs scaled to L_g = 184 nm were fabricated and show a peak f_T of 35 GHz, current drive of 112 mA/mm and breakdown voltages exceeding 4.5 V whereas the nominal CMOS voltage was less than 1V on the same process. The devices were characterized from DC to 40 GHz and an industry standard TOM3 model has been developed describing their operation. A board level Class AB power amplifier operating at 433 MHz was designed, fabricated and measured to have a peak output power of 17 dBm and peak PAE of 42.5%. The supply voltage of the PA was more than twice the breakdown voltage of corresponding CMOS on the same semiconductor process. The measured PA results were used to validate the model across different bias and input power level conditions.