Cryogenic investigation of gate leakage and RF performances down to 50K of 0.2 mu m AlInAs/GaInAs/InP HEMTs

0.2 mu m Al_0.48In_0.52As/Ga_0.47In_0.53As LMHEMT on InP with an undoped GaInAs layer to reduce gate leakage have been realised and their DC and RF properties have been investigated at cryogenic temperatures. The cutoff maximum frequencies of oscillation F_max up to 260 GHz are extrapolated at 50K from the maximum unilateral gain (MUG) determined using S-parameters measured up to 40 GHz, Evolution of gate leakage current and RF characteristics against gate and drain biases are presented between 50 and 300K.