An ultra-low dark current CMOS image sensor cell using n+ ring reset

Abstract

We present in this letter for the first time a new CMOS image sensor cell using n+-ring-reset structure, which can isolate the photon-sensing area from the defective field oxide edge. The experimental results demonstrate that the severe dark current degradation of the conventional CMOS active pixel image sensor fabricated by a standard CMOS logic process is significantly alleviated. Through optimizing the layout arrangement, as high as 45% fill factor can be obtained. The dynamic range of this new cell can thus be improved by more than 10× compared to a conventional cell.