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A 128 128 CMOS imager that permits synchronous capture is presented. The sensor combines the best of CMOS imagers (low-power, random readout, nondestructive readout, single supply voltage…) and synchronous capture [available in high-end charge coupled device (CCD) imagers]. The key point in obtaining such characteristics is the separation of the photosensor and the storage element. Although some sensors with these characteristics have been reported, in this sensor, the storage capability has been brought a step further, having storage times in the order of tens of seconds, and being able to use the array itself as a random access memory (RAM). This could avoid the use of external RAM, making the system simpler, more compact, and of low-power consumption.Index Terms-Active pixel sensor, analog memory, CMOS image sensors, machine vision.

The damage created in SiO2 layers by low-energy Ar ions (130 keV) and the reconstruction of the structure after various annealing steps have been characterized as a function of the implantation dose. Quantitative determinations of the damage produced have been performed from infrared spectroscopy. We show that two dose thresholds for damage are encountered: At 1014 cm−2 damage saturates and for doses above 1017 cm−2 sputtering effects dominate. Annealing at high temperatures (1100 °C) restores the structure of the initial nonimplanted oxide only for doses below the second threshold, although some disorder remains. Electroluminescence measurements show that annealing is able to eliminate electrically active defects. For implantation doses greater than 1017 cm−2, annealing is unable to restore the structure completely as sputtering effects create a depleted oxygen layer at the surface and substoichiometric defects appear. The presence of microcavities created by the Ar atoms at such high doses may affect the annealing behavior.

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