Scaled-footprint ultra-low power cryogenic InGaAs/InP HEMTs with record-high combination of low-noise and high-frequency performance

In this work we demonstrate cryogenic In $_x Ga_(1-x) As / InP$ HEMTs with highly scaled gate footprints, down to 380 x 40 nm2 for a single gate finger, and investigate the impact of footprint scaling on device performance. The 80% In channel devices show $f_T = 622 GHz and$ f_{MAX} $= 733 GHz$ together with a noise indication factor $√(I_D)/gm = 0.17 √(V∙mm/S)$ at 4 K, which is a record-high combination of high-frequency and low-noise performance. The performance is enabled by heterostructure engineering, resulting in ultra-low $R_{ON} = 250 Ω·µm together with a minimum subthreshold swing$ SS < 10 mV/decade $. These results show that cryogenic III-V HEMT technology can provide excellent performance at scaled footprints for readout in future high-density quantum systems.