Investigation of Radiation-Hardened Charge-Coupled Devices.

Abstract : This report describes a study of techniques for improving the performance of CCDs in a nuclear radiation environment. A test chip with both n-surface- and n-buried-channel devices (128-stage four-phase registers) utilizing a double-polysilicon overlapping gate structure was designed, fabricated with low-temperature, pyrogenically-grown channel oxides, and tested. The chip also contains threshold tracking circuits designed to automatically correct for threshold shifts induced by ionizing radiation as well as automatic input and output biasing circuits to provide a radiation-hardened means of injecting and detecting CCD signals. The devices were subjected to high energy (1 MeV) electron radiation and the optimum circuit techniques to improve the radiation tolerance of CCDs were determined. (Author)