Cryogenic microwave performance of 0.5-μm InGaAs MESFET's

Microwave and DC properties of 0.5-μm InGaAs MESFETs were measured at 300 and 125 K. The authors have measured approximately 30% increases in RF g_m|ext and f_T when cooling from 300 to 125 K. The authors also observe a 0.06-V increase in gate built-in voltage at 125 K that results in smaller gate leakage currents. The improved gate characteristic at 125 K leads to better RF properties at higher gate bias