On-wafer microwave measurement setup for investigations on HEMTs and high-T/sub c/ superconductors at cryogenic temperatures down to 20 K

An on-wafer measurement setup for the microwave characterization of HEMTs and high-T/sub c/ superconductors at temperatures down to 20 K is presented. Both S-parameter and noise measurements can be performed in the frequency range from 45 MHz to 40 GHz and 2 GHz to 18 GHz, respectively, using standard calibration techniques and commercial microwave probe tips. Microwave measurements on a pseudomorphic FET and an AlGaAs-GaAs HEMT as well as investigations on a superconducting filter are presented to demonstrate the efficiency of the developed system.>