Leakage-Preventing Design of Snapshot Photodiode CMOS Imager

A new design for a complementary metal oxide/semiconductor (CMOS) snapshot imaging device of the photodiode-based, active-pixel-sensor (APS) type calls for features to prevent photogenerated electric charges collected during a given frame period from leaking into in-pixel capacitors that store charges collected during the preceding frame period, pending completion of readout from that period. The proposed design would also utilize the electronic-shuttering capability of an APS to provide for programmable exposure time, down to (≈10μs) a small fraction of the frame period, to enable faithful recording of images of rapidly moving objects. Finally, the design would make it possible to obtain quantum efficiency higher and readout noise lower than those of a typical prior CMOS APS imaging device.