Studying charge-trapping defects within the silicon lattice of a p-channel CCD using a single-trap "pumping" technique

The goals of future space missions such as Euclid require unprecedented positional accuracy from the responsible detector. Charge coupled devices (CCDs) can be manufactured with exceptional charge transfer properties; however the harsh radiation environment of space leads to damage within the silicon lattice, predominantly through proton collisions. The resulting lattice defects can trap charge, degrading the positional accuracy and reducing the useful operating time of a detector. Mitigation of such effects requires precise knowledge of defects and their effects on charge transfer within a CCD. We have used the technique of single-trap "pumping" to study two such charge trapping defects; the silicon divacancy and the carbon interstitial, in a p-channel CCD. We show this technique can be used to give accurate information about trap parameters required for radiation damage models and correction algorithms. We also discuss some unexpected results from studying defects in this way.