Cryogenic Temperature Electrical Characterization of Enhancement-Mode Thin Barrier AlGaN/GaN HEMT With Hybrid Ferroelectric Charge Trap Gate-Stack

This work reports on the fabrication and cryogenic temperature characterization of a high-electron-mobility transistor (HEMT) featuring a 6nm AlGaN thin barrier and a hybrid ferroelectric gate-stack to achieve E-mode operation. DC and transmission line method (TLM) measurements were performed down to 4K to investigate the device performance and contact resistance behavior at cryogenic temperatures. We achieved a subthreshold slope (SS) of ~47.5mV/dec at 4K, along with a high maximum drain current of 1.055 A/mm at V${}_{\text {DS}}= {14}$V (at 20K) and a remarkably high currenton/offratio (Ion/Ioff) of$6.6\times 10^{{10}}$at 4K. The hybrid gate architecture demonstrated stable operation with preserved ferroelectric functionality. Temperature-dependent analysis revealed insights into carrier transport, mobility degradation, sheet, and contact resistivity. These results demonstrate the potential of ferroelectric-gated HEMTs for cryogenic applications.