Shot Noise in Platinum-Gallium Arsenide Schottky Barrier Diodes

The high-frequency shot noise of Pt–GaAs Schottky barrier diodes has been measured at 60 MHz for both guard-ring and non-guard-ring structures. The measured equivalent noise temperature agrees well with the shot-noise theory of semiconductor junctions at relatively high forward currents where the metal-semiconductor interface effects can be neglected. At low levels of forward bias the measured noise is greater than that predicted by conventional theory. A measured excess-leakage conductance showing full thermal noise is added to the model and accounts for part of the difference between theory and experiment. The requirements for low-noise diodes are outlined.