LOW-TEMPERATURE LOW-VOLTAGE OPERATION OF HEMTS ON INP

Pseudomorphic single recessed Al.48In.52As/Ga.30In.70As/AlInAs pseudomorphic HEMTs (PM-HEMT) on InP with planar doping and gatelength 0.2mum are investigated at cryogenic temperatures (50K) for their high frequency intrinsic transport properties at low drain bias voltage. Transient drain current measurements are compared with DC characteristics and show the evolution of trapping effects versus drain voltage. HF measurements show that at low temperature drain current saturates at drain voltage as low as 0.5V with nearly maximum transconductance (almost-equal-to 800mS/mm) and very high intrinsic cut-off frequency (almost-equal-to 190GHz). In these ultrashort gate HEMTs, cryogenic temperatures bring the best relative improvement of intrinsic device transport properties (almost-equal-to 60%) at very low drain voltages (0.5V).