CMOS active pixel structure
AssigneeNew Imaging Technologies
InventorYang Ni
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Abstract
The invention concerns a structure of a CMOS active pixel, comprising a semi-conductive substrate (1) of a first type, at least one first photodiode operating in photovoltaic mode comprising a photovoltaic conversion area (2) defined by a doped area of a second type forming a PN junction with the substrate, said first photodiode re-emitting photoelectric charge carriers collected by the PN junction during the exposure of said first photodiode to a light, at least one second photodiode operating in integration mode and reverse-biased, said second photodiode comprising a charge accumulation area (3) defined by a doped area of the second type forming a PN junction with the substrate, said charge accumulation area being exposed to the charge carriers from the photovoltaic conversion area (2) in order to accumulate such charge carriers.
Claims17
An active pixel structure of CMOS type, comprising:
- a semiconductor substrate of a first type,
- at least one first photodiode configured to operate in photovoltaic mode during exposure of said first photodiode to radiation, comprising a photovoltaic conversion region defined by a doped region of a second type forming a PN junction with the substrate, said first photodiode being configured to re-emit photoelectric charge carriers captured by the PN junction during exposure of said first photodiode to radiation;
- at least one second photodiode configured to operate in integration mode and to be reverse biased during exposure of said first photodiode to radiation, said second photodiode comprising a charge accumulation region defined by a doped region of the second type forming a PN junction with the substrate, said charge accumulation region being configured to be exposed to the charge carriers originating from the photovoltaic conversion region so as to accumulate said charge carriers;
- and
- at least one readout circuit to read the voltage of the first photodiode and to read charge measurement at the second photodiode.
Dependencies are inferred from the claim text.