Temperature dependence of noise in a GaAs metal-semiconductor field effect transistor at microwave frequencies

Measurements of the noise parameters of a GaAs metal-semiconductor field effect transistor (MESFET) show the minimum noise figure decreases exponentially into the noise floor with decreasing temperature for most frequencies from 2 to 18 GHz and for most currents. The MESFET noise has a thermal activation energy of ∼55meV which is almost half the value seen in a pseudomorphic high electron mobility field effect transistor (pHEMT). Unlike in the pHEMT, the high-temperature coefficient to the activated behavior for the MESFET is independent of current and frequency.