Electron and neutron radiation damage effects on a two-phase CCD

Surface and bulk radiation damage effects on a two-phase charge-coupled device (CCD), operated in a multipinned phase (MPP) mode have been evaluated. Two-phase CCD's are one of the candidates for application in the vertex detector of a future linear collider. Flat-band voltage shifts, dark current, dark current spikes, and charge transfer efficiency (CTE) were studied on devices subjected to irradiation with fluences reaching 4.3/spl times/10/sup 12/ electrons/cm/sup 2/ and 8.9/spl times/10/sup 9/ neutrons/cm/sup 2/. An additional source of dark signal in electron irradiated devices was observed and explained by impact ionization by holes, released by tunneling from defect states near the Si-SiO/sub 2/ interface. A model for the CTE in a two-phase CCD as a function of temperature, background charges, and clock timing is described. Calculations based on the model are in good agreement with the experimentally determined values of CTE in electron and neutron irradiated CCD's.