NEARLY NOISE-FREE TRANSISTOR OPERATED IN THE 2-18 GHZ RANGE

Temperature dependent measurements of the noise parameters of a pseudo morphic high electron mobility transistor show the minimum noise figur e vanishes at low temperatures for frequencies from 2 GHz up to 18 GHz and for most currents. We propose that the exponential decrease seen in the noise figure with temperature is due to a reduction of thermall y activated noise sources with an activation energy of similar to 95 m eV. Other noise-parameter data suggest a flattening of the noise figur e paraboloid as temperature is decreased. These results demonstrate th e feasibility of designing a near 0.1 dB noise figure amplifier for hi gh-frequency operation over a wide range of currents. (C) 1998 America n Institute of Physics.