Cryogenic RF Small-Signal Modeling and Parameter Extraction of SiGe HBTs

In this paper RF small-signal modeling of SiGe HBTs was presented and its variation with biasing current, voltage and temperatures were discussed especially with the cryogenic temperatures. Direct extraction process and a two-step hot-after-cold optimization were successfully fitted with 1 to 35 GHz Y-parameters. The cryogenic RF circuit and equivalent circuit parameters were examined for its temperature dependence performances.