An approach to modeling total dose ionizing radiation effects in Hg(1-x)Cd(x)Te photodiodes using Pisces II-B

We have modified a 2D numerical device simulator to account for the electrical characteristics of mercury cadmium telluride (MCT), and compared the simulated current-voltage (I-V) results with measurements. For diodes not dominated by tunneling or other surface effects, the simulated curves match the measurement within the experimental limitations. The modified code can now be used to investigate the changes in the I-V characteristics of irradiated diodes by adding the appropriate models. We show the results of an investigation of the band-to-band tunneling in these diodes, which theory predicts is a dominant current-producing mechanism after irradiation. The I-V curves closely match those of irradiated diodes if radiation-induced trapped surface charge is taken into account. (Author)