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

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.