InAs/AlSb HEMTs for cryogenic LNAs at ultra-low power dissipation

Properties of the InAs/AlSb high electron mobility transistor, essential for the design of a cryogenic low-noise amplifier (LNA) operating at low power dissipation, have been studied. Upon cooling from 300 K to 77 K, the dc transconductance gm was enhanced by 30% at a drain-source voltage VDS of 0.1 V. The gate current leakage showed a strong reduction of the Schottky current component at 77 K. Compared to 300 K, the cut-off frequency fT and maximum oscillation frequency fmax showed a significant improvement at 77 K with a peak fT (fmax) of 167 (142) GHz at VDS = 0.2 V. The suitability of the Sb HEMT for a cryogenic LNA design up to 50 GHz, operating at low dc power dissipation, was investigated through the extraction of the NFtot,min figure of merit. It was found that the best device performance in terms of noise and gain is achieved at a low VDS of 0.16 V resulting in a minimum NFtot,min of 0.6 dB for a frequency of 10 GHz when operating at 77 K. A benchmarking between the Sb HEMT and an InP HEMT has been conducted highlighting the device improvement in noise and gain required to reach today’s state-of-the-art cryogenic LNAs.

► Cryogenic properties of InAs/AlSb HEMTs with planar technology are investigated.
► Upon cooling, DC measurements show saturation of IDS, lower RON and reduced IG.
► Strong improvements are observed also in fT and fmax at low VDS below 0.2 V.
► Extraction of noise measure M confirm that noise and gain are improved upon cooling.
► The improvements make the Sb HEMT candidate for ultra low power cryogenic LNA.