28 FDSOI RF Figures of Merits and Parasitic Elements at Cryogenic Temperature

This work presents, for the first time to our best knowledge, RF characterization of 28 nm FDSOI CMOS process at cryogenic temperatures including extraction of parasitic elements of small-signal equivalent circuit and two main RF Figures of Merit (FoM), i.e. current cutoff frequency (fT) and maximum oscillation frequency (fmax). Increases of fT and fmax by about 85 GHz and 30 GHz, respectively, are demonstrated at cryogenic temperatures. The observed behavior of RF FoMs versus temperature is analyzed in terms of small-signal equivalent circuit elements. This study suggests 28 nm FDSOI as a good candidate for future cryogenic applications.