Effects of space radiation damage and temperature on the noise in CCDs and LDD MOS transistors

Lightly doped drain (LDD) MOS transistors were subjected to proton radiation damage representative of the damage they would receive on a typical orbital space telescope mission. The noise spectral density was measured as a function of gate voltage, temperature and total radiation dose. These data were used to model the resultant noise lower limit read for that transistor when used as the charge-conversion, output stage of a charge-coupled-device (CDD) imaging array detector. Very clear evidence of excess noise being added to the CCD output as a function of radiation was found. It is possible to select combinations of temperature, CCD dual-correlated sample time constant and gate voltage which minimize the performance degradation due to this excess noise