DC and RF Variability of SiGe HBTs Operating Down to Deep Cryogenic Temperatures. - Hanbin Ying; Jeffrey W. Teng; George N. Tzintzarov; Anup P. Omprakash; Sunil G. Rao; Uppili S. Raghunathan; Adrian Ildefonso; Martin S. Fernandez; John D. Cressler (BCICTS, 2019)