Power gain and noise of InP and GaAs insulated gate microwave FETs

LPE GaAs and InP n-channel depletion mode insulated gate field effect transistors (MISFETs) having 4 μm gate lengths have been fabricated employing pyrolytic Si _xO _yN _z, pyrolytic SiO ₂ and an anodic dielectric for gate insulation. The microwave power gain, noise figure, maximum output power and power-added efficiency were measured and compared to those parameters measured on GaAs Schottky barrier gate devices of identical geometry. The results show that, at least at the microwave frequencies measured, power gain and noise are essentially the same in the GaAs Schottky gate FET and anodic MISFET devices while the maximum output power of a typical InP MISFET was greater than that of a representative GaAs Schottky device.