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CMOS image sensor hardness under irradiation is a key parameter for application fields such as space or medical. In this paper, four commercial sensors featuring different technological characteristics (pitch, isolation or buried oxide) have been irradiated with ^60Co source. Based on dark current and temporal noise analysis, we develop and propose a phenomenological model to explain pixel performance degradation. [ABSTRACT FROM AUTHOR]

This paper presents an investigation of Total Ionizing Dose (TID) induced dark current sources in Pinned PhotoDiodes (PPD) CMOS Image Sensors based on pixel design variations. The influence of several layout parameters is studied. Only one parameter is changed at a time enabling the direct evaluation of its contribution to the observed device degradation. By this approach, the origin of radiation induced dark current in PPD is localized on the pixel layout. The PPD peripheral shallow trench isolation does not seem to play a role in the degradation. The PPD area and a transfer gate contribution independent of the pixel dimensions appear to be the main sources of the TID induced dark current increase. This study also demonstrates that applying a negative voltage on the transfer gate during integration strongly reduces the radiation induced dark current. [ABSTRACT FROM AUTHOR]

Abstract: A new plasma induced damage mechanism on CMOS image sensor is analyzed. An increase of the mean pixel dark current is observed after the plasma etch of a cavity on the pixel area. The degradation increases non-linearly when the dielectric layers between the photodiode and the plasma become thinner. This can be explained by a photo generation phenomenon in the dielectric nitride layer, induced by the plasma UV, and assisted by the wafer surface charge. This mechanism leads to the creation of a positive fixed charge on the pixel surface, which can next deplete the top P layer of the pinned photodiode. The temperature dependence of the dark current again demonstrates that the degradation is mainly due to a diode surface generation effect. Process and pixel architecture optimization are finally proposed. [Copyright &y& Elsevier]