Cold-source cryogenic characterization and modeling of a mHEMT process

An extensive measurement campaign, including DC curves, S-parameters and noise factor has been carried out on a 70 nm mHEMT technology (OMMIC's D007IH), both at ambient (300 K) and cryogenic (30 K) temperatures. For the first time, to the Authors' knowledge, the feasibility of the cold-source technique for on-wafer, cryogenic noise measurements is demonstrated. A scalable equivalent-circuit model, also equipped with noise parameters according to Pospieszalski's approach, has been extracted for the cryo-cooled devices. Comparisons between ambient and cryogenic operation are provided and discussed.