Noise behavior of GaAs field-effect transistors with short gate lengths

Abstract

The noise behavior of the GaAs Schottky-barrier gate field-effect transistor has been investigated theoretically and experimentally. It has been found that an additional noise source has to be taken into account in GaAs FET's biased in the pinchoff region: the intervalley scattering noise. This noise source has been investigated and a new transistor noise model is proposed. Measured and calculated noise figures show good agreement in the frequency range 2-10 GHz. It is shown that the influence of the intervalley scattering noise can be reduced by reducing the channel thickness, and that such devices show excellent gain and noise properties in the X band.