Current voltage modeling of current limiting mechanisms in HgCdTe focal plane array photodetectors

An automated iterative nonlinear fitting program has been developed to model current-voltage (I-V) data measured on HgCdTe infrared (IR) detector diodes. This model includes the ideal diode diffusion, generation-recombination, bandto-band tunneling, trap-assisted tunneling (TAT), and avalanche breakdown as potential current limiting mechanisms in an IR detector diode. The modeling presented herein allows one to easily distinguish, and more importantly to quantitatively compare, the amount of influence each current limiting mechanism has on various detectors' I-V characteristics. Longer cutoff wavelength detectors often exhibit significant current limitations due to tunneling processes. The temperature dependence of these tunneling characteristics is thoroughly investigated for two diodes.