Influence of Terrestrial Cosmic Rays on the Reliability of CCD Image Sensors—Part 2: Experiments at Elevated Temperature

An aging effect in solid-state image sensors is studied: the generation of hard errors resulting in hot spots, warm pixels, or white pixels. This effect even occurs in image sensors that are simply stored on the shelf. The first paper described experiments that were set up to prove that the main origin can be found with neutrons that create displacement damage in the silicon bulk. These neutrons are part of terrestrial cosmic rays. This second paper is based on measurements done on devices that were stored on the shelf, but at elevated temperatures. In addition, annealing experiments were performed on packaged devices. The creation of these hot spots is independent of technology, architecture, sensor type, or sensor vendor, and it is observed in CCDs as well as in CMOS image sensors. However, the generation, and particularly the stability, of the hot spots seems to depend strongly on the storage temperature or on the annealing temperature.