Temperature variable noise and electrical characteristics of Au-Ga-As Schottky barrier millimeter-wave mixer diodes

The fabrication and characterization of gold-gallium arsenide Schottky-barrier diodes on molecular-beam-epitaxy (MBE)-grown epitaxial gallium arsenide intended for cryogenic millimeter-wave mixer applications is reported. The Schottky barriers were formed either by pulse plating or by in situ evaporation in the MBE system after the epitaxial growth. The equivalent temperature as derived from the current-voltage characteristic is considerably lower at high current densities and cryogenic temperature than for the more commonly used Pt-GaAs Schottky diode. Noise-generation mechanisms are investigated as a function of forward bias and temperature. At cryogenic temperature, a best equivalent noise temperature of 22 K was obtained at 4 GHz for a DC-biased diode.<
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