ABSTRACT
Random telegraph noise (RTN), a discrete fluctuation in the electron current, is common in submicron devices. We observed bistable fluctuations in the dark current of longwavelength HgCdTe photodiodes. The RTN had several anomalous characteristics but we found some results that suggest an RTN mechanism in the photodiodes. We also found the structures in the reverse bias current-voltage characteristics in the form of increasing steps in the leakage current. The temperature dependencies of both the RTN and the steps on the leakage current suggests that both phenomena originated from the same tunneling. We propose that this tunneling occurred at inclusion-defects in the depletion layer. The capacitance-voltage characteristics of the diode suggested that the inclusions exist in the depletion layer. The kind of defects is still unclear. We propose that the most likely mechanism for RTN is the modulation of the barrier height of the tunneling by the change in the charge state near the inclusion-defects.
