Low-noise millimeter-wave mixer diodes prepared by molecular beam epitaxy (MBE)

Abstract
Schottky barrier diodes which are specifically designed for use in cryogenically cooled millimeter‐wave mixers have been fabricated from MBE layers grown on heavily doped GaAs substrates. At 15 K the devices show a nearly exponential current‐voltage characteristic and a diode noise temperature which is determined predominantly by the tunneling transport mechanism. A diode noise temperature as low as 55 K was achieved under pumped conditions. This is the lowest diode noise temperature ever obtained in a resistive mixer. A single sideband mixer noise temperature of 315 K was measured at 102 GHz for a cryogenic mixer employing these diodes.