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Nowadays, CMOS image sensors are widely considered for space applications. The use of CIS (CMOS Image sensor)
processes has significantly enhanced their performances such as dark current, quantum efficiency and conversion gain.
However, in order to fulfil specific space mission requirements, dedicated research and development work has to be
performed to address specific detector performance issues. This is especially the case for dynamic range improvement
through output voltage swing optimisation, control of conversion gain and noise reduction. These issues have been
addressed in a 0.35μm CIS process, based on a large volume CMOS foundry, by several joint ISAE- EADS Astrium
R&D programs. These results have been applied to the development of the visible and near-infrared multi-linear imager
for the SENTINEL 2 mission (LEO Earth observation mission for the Global Measurement Environment and Security
program). For this high performance multi-linear device, output voltage swing improvement is achieved by process
optimisation done in collaboration with foundry. Conversion gain control is also achieved for each spectral band by
managing photodiode capacitance. A low noise level at sensor output is reached by the use of an architecture allowing
Correlated Double Sampling readout in order to eliminate reset noise (KTC noise). KTC noise elimination reveals noisy
pixels due to RTS noise. Optimisation of transistors's dimensions, taking into account conversion gain constraints, is
done to minimise these noisy pixels. Additional features have been also designed: 1) Due to different integration times
between spectral bands required by mission, a specific readout mode was developed in order to avoid electrical
perturbations during the integration time and readout. This readout mode leads to specific power supply architecture.
2)Post processing steps can be achieved by alignment marks design allowing a very good accuracy. These alignment
marks can be used for a black coating deposition between spectral bands (pixel line) in order to minimise straight light
effects. In conclusion a review of design improvements and performances of the final component is performed.
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