On-Wafer, Cryogenic Characterization of Ultra-Low Noise HEMT Devices

Significant advances in the development of high electron-mobility field-effect transistors (HEMTs) have resulted in cryogenic, low-noise amplifiers (LNAs) whose noise temperatures are within an order of magnitude of the quantum noise limit (hf/k). Further advances in HEMT technology at cryogenic temperatures may eventually lead to the replacement of maser and superconducting–insulator– superconducting front ends in the 1to 100-GHz frequency band. Key to identification of the best HEMTs and optimization of cryogenic LNAs are accurate and repeatable device measurements at cryogenic temperatures. This article describes the design and operation of a cryogenic coplanar waveguide probe system for the characterization and modeling of advanced semiconductor transistors at cryogenic temperatures. Results on advanced HEMT devices are presented to illustrate the utility of the measurement system.