Dark current limitations in p-type Hg1-xCdxTe MIS devices

The potential of HgCdTe MIS devices for use in future generation infrared systems is determined by the magnitude of the respective dark current contributions associated with minority carrier diffusion, generation-recombination in the depletion region, and tunneling by direct band-to-band or via bandgap state transitions. Data on p-type Hg1-xCdxTe MIS devices with 0.2 < × < 0.3 indicate that any or all three of these dark current components can dominate diode performance, depending on conditions of operation. Tunneling via bandgap states has been unambiguously identified by the observation for the first time of quantum oscillations in HgCdTe MIS admittance data at 77K associated with tunneling of electrons into quantized electric sub-bands in the inversion layer from the valence band via Shockley-Read centers located in the depletion region.