Cumulated dose long term effects in charge coupled devices

Dark current postirradiation evolution in Charge Coupled Devices (CCD) has been experimentally studied versus time and temperature. Early work shows that this current still increases after irradiation over thousands of hours at 300 K. Raising the temperature tends to increase or decrease the dark current, depending on postirradiation experimental conditions. The results can be interpreted, either considering the interface states density, or using the dependence of generation rate on surface potential. The authors show that thermal activation in irradiation tests must be used only after a critical analysis of physical mechanisms and device structure