Characterization and modeling of the mobility, threshold voltage, and subthreshold swing in p-GaN gate HEMTs at cryogenic temperatures

This study presents a comprehensive investigation of the electrical properties of p-GaN gate HEMT devices under cryogenic operations, spanning a temperature range from 300 K all the way down to 10 K. We report achievement of a low sub-60 mV/dec sub-threshold swing (SS) (33.2 mV/dec at 10 K), a high ION/IOFF ratio (∼3.5 × 1010 at 10 K), and a remarkable ID,max (∼358 mA/mm at 10 K) in p-GaN gate HEMTs operating under cryogenic conditions. Furthermore, the mobility, threshold voltage shifts, and SS characteristics at cryogenic temperatures are modeled in p-GaN HEMTs. In summary, p-GaN gate HEMTs are promising for cryogenic applications due to their low SS, high gm,max, impressive ION/IOFF ratio, and substantial ID,max. Furthermore, the modeling achieved in this work can pave the way for future characteristic prediction in p-GaN HEMTs at cryogenic temperatures.