Comparison of the low noise performance of GaN HEMTs and MIS-HEMTs at cryogenic temperatures

This work presents the comparison of the noise performance of AlGaN/ GaN MIS-HEMTs and HEMTs at cryogenic temperatures. Wideband noise measurements at a physical temperature of similar to 4 K were performed in order to extract the noise characteristics of the devices, within the range of frequencies of 3 - 7 GHz. A DC and RF characterization of the devices are also presented to further assess their cryogenic performances. Over the measured frequency band, the results indicate that both technologies are able to present an average best noise temperature as low as 8 K. The MIS-HEMT presents a slight advantage at low bias condition, mainly due to its reduced gate capacitance. The presented results are the first report on the microwave low-noise performance of cryogenic GaN MIS-HEMT, and constitute their current state-of the art.