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US 9,093,353 B2Granted
Matrix image sensor providing bidirectional charge transfer with asymmetric gates
AssigneeE2V Semiconductors
InventorFrédéric Mayer
Life of this patent
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AssigneeE2V Semiconductors
InventorFrédéric Mayer
Estimating the term…
In the field of image sensors, more particularly time-delay integration linear sensors or TDI sensors, a sensor comprises rows of photodiodes alternating with rows of gates adjacent to the photodiodes. The gates are asymmetric, adjacent on one side to a photodiode and having, on the other side, narrow gate fingers extending toward another photodiode. Owing to their very narrow width, the fingers endow the transfer of charges with a directionality. Between two successive photodiodes there are two gates, the two being adjacent to the two photodiodes, the first having its narrow fingers turned toward the first photodiode, the second having its narrow fingers turned toward the second photodiode. The direction of transfer of the charges in the sensor may be chosen by neutralizing either the first gate or the second gate, the other gate receiving alternating potentials allowing the transfer of charges from one photodiode to the other.
An image sensor using charge transfer, the sensor comprising rows of photodiodes alternating with rows of gates adjacent to the photodiodes, the gates covering a semiconductor active layer region of a first type of conductivity and the photodiodes being formed in the semiconductor active layer by individual regions of a second type of conductivity, themselves covered by individual superficial regions of the first type, connected to a reference potential for the semiconductor active layer, wherein the image sensor comprises at least two independent gates exhibiting an asymmetry between an upstream side and a downstream side, each independent gate being adjacent on one side to a photodiode and having, on another side, narrow gate fingers extending toward another photodiode, the narrow fingers being separated from one another by insulating regions doped with the first type of conductivity, more doped than said individual superficial regions and also connected to the reference potential of the active layer, a first gate among the two independent gates having its narrow fingers extending toward a first photodiode belonging to a first row of photodiodes and a second gate among the two independent gates having its narrow fingers extending toward a second photodiode belonging to a second row of photodiodes, and the two independent gates being controllable separately from each other.
Dependencies are inferred from the claim text.