S-Parameter, I-V Curve and Noise Figure Measurements of III-V Devices at Cryogenic Temperatures

We have measured the electrical operating parameters for several three-terminal semiconductor III-V devices at both room temperature and liquid nitrogen temperature, 80 K. The fundamental performance parameters, I-V curve, S-parameters and noise figure, change quite dramatically upon cooling. It is necessary to know these parameters if an optimal cryogenic device, e.g. high-temperature superconducting/III-V hybrid, is to be designed and fabricated. The electrical operating parameters for a Fujitsu GaAs high electron mobility field effect transistor, HEMT, and a Litton GaAs metal semiconductor field effect transistor, MESFET, were measured at room temperature and at 80 K. The data collected on these devices were used to design a III-V C-band amplifier with optimum operation at 80 K. This amplifier was used to construct a high-temperature superconducting/III-V hybrid oscillator, a major step towards the high degree of circuit integration required for a useful HTS/III-V hybrid subsystem or system.