Radiation induced interface trap limited storage times in 10 micron cutoff wavelength (Hg,Cd)Te MIS capacitors

Dark storage times were measured as a function of temperature over a temperature range of 50 to 80 K for 10-μm cutoff wavelength (77 K) p-type (Hg,Cd)Te/anodic oxide/ZnS metal-insulator-semiconductor (MIS) capacitors prior to and after Co-60 gamma irradiation to doses of 5×10⁵ and 1×10⁶ rad (Si). The radiation-induced interface trap density near midgap for these doses was 8×10¹¹ and 1.6×10¹²/eV-cm², respectively. A decrease in the storage time was observed for both doses and is attributed to thermal generation through the radiation-induced interface traps and to interface-trap-assisted tunneling. The radiation-induced dark current responsible for the storage time degradation is 1.8×10^-4 A/cm² at 50 K after a dose of 1×10⁶ rad (Si)