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 similar to 55 meV 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. (C) 1998 American Institute of Physics. [S0003-6951(98)05041-4].