Low-Temperature Radiation Damage Effects in a Room-Temperature Radiation-Hard Surface Channel CCD

Room temperature radiation hard p-surface channel CCD´s were irradiated at 85°K with 2 MeV electrons while being operated as dynamic shift registers. The increased charge trapping in the oxide at liquid nitrogen temperatures produced an input gate threshold voltage shift of -5.6V at 4×104 rads as compared to a -2.2V shift after 1×106 rads at 300°K. Except for the input gate voltage, the devices could be operated with the pre-irradiation clock and bias voltages after receiving 4×104 rads. A 20% increase in the signal handling capacity was observed after 3×104 rads. The output source-follower gain increased by approximately 10% after 4×104 rads. The excess flat-band voltage shift and increased transfer inefficiency was annealed by warming the device to 300°K with all clock and bias voltages applied.