Method and apparatus for controlling charge transfer in CMOS sensors with a transfer gate work function
First Claim
Patent Images
1. An image sensor integrated circuit, comprising:
- a plurality of photodetectors generating electrons excited by incident photons;
a plurality of nodes, wherein each of the plurality of photodetectors has a corresponding node of the plurality of nodes;
a plurality of transfer devices controlling a transfer of the electrons from said each of the plurality of photodetectors to the corresponding node, each of the plurality of transfer devices including;
a first terminal coupled to one of the plurality of photodetectors;
a second terminal coupled to one of the plurality of nodes; and
a body between the first terminal and the second terminal; and
a control terminal electrically coupled to the body, wherein the transfer of the electrons occurs through the body between the first terminal and the second terminal in response to a control voltage of sufficient value applied to the control terminal, and in an absence of the control voltage the control terminal creates an electric field tending to repel the electrons from a portion of the body by the control terminal;
a plurality of reset devices, wherein each of the plurality of nodes has a corresponding reset device of the plurality of reset devices, and said each of the plurality of nodes is reset when the corresponding reset device is active;
row and column circuitry; and
a plurality of signal devices coupling the plurality of nodes to the row and column circuitry.
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Abstract
An improved CMOS sensor integrated circuit is disclosed, along with methods of making the circuit and computer readable descriptions of the circuit.
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Citations
26 Claims
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1. An image sensor integrated circuit, comprising:
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a plurality of photodetectors generating electrons excited by incident photons;
a plurality of nodes, wherein each of the plurality of photodetectors has a corresponding node of the plurality of nodes;
a plurality of transfer devices controlling a transfer of the electrons from said each of the plurality of photodetectors to the corresponding node, each of the plurality of transfer devices including;
a first terminal coupled to one of the plurality of photodetectors;
a second terminal coupled to one of the plurality of nodes; and
a body between the first terminal and the second terminal; and
a control terminal electrically coupled to the body, wherein the transfer of the electrons occurs through the body between the first terminal and the second terminal in response to a control voltage of sufficient value applied to the control terminal, and in an absence of the control voltage the control terminal creates an electric field tending to repel the electrons from a portion of the body by the control terminal;
a plurality of reset devices, wherein each of the plurality of nodes has a corresponding reset device of the plurality of reset devices, and said each of the plurality of nodes is reset when the corresponding reset device is active;
row and column circuitry; and
a plurality of signal devices coupling the plurality of nodes to the row and column circuitry. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of fabricating an image sensor integrated circuit having a plurality of photodetectors using energy of photons reaching the plurality of photodetectors to excite electrons;
- a plurality of nodes, each of the plurality of photodetectors having a corresponding node of the plurality of nodes;
a plurality of transfer devices each with a first terminal coupled to one of the plurality of photodetectors, a second terminal coupled to the corresponding node, a body between the first terminal and the second terminal, and a control terminal;
a plurality of reset devices, each of the plurality of nodes having a corresponding reset device of the plurality of reset devices, and said each of the plurality of nodes is reset when the corresponding reset device is active; and
a plurality of signal devices coupling the plurality of nodes to row and column circuitry;
the method comprising;
implanting an n-type region for each of the plurality of photodetectors, the n-type region receiving the electrons excited by the energy of the photons;
depositing the control terminal for each of the plurality of transfer devices wherein the transfer of the electrons occurs through the body between the first terminal and the second terminal in response to a control voltage of sufficient value applied to the control terminal, and in an absence of the control voltage the control terminal creates an electric field tending to repel the electrons from a portion of the body by the control terminal;
implanting the plurality of nodes, wherein each of the plurality of photodetectors has a corresponding node of the plurality of nodes where the electrons are measured prior to removal; and
implanting at least one n+terminal for each of the plurality of transfer devices, wherein said method forms row and column circuitry on the image sensor integrated circuit accessing the plurality of nodes. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
- a plurality of nodes, each of the plurality of photodetectors having a corresponding node of the plurality of nodes;
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26. A computer readable description of an image sensor integrated circuit comprising:
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a plurality of photodetectors generating electrons excited by incident photons;
a plurality of nodes, wherein each of the plurality of photodetectors has a corresponding node of the plurality of nodes;
a plurality of transfer devices controlling a transfer of the electrons from said each of the plurality of photodetectors to the corresponding node, each of the plurality of transfer devices including;
a first terminal coupled to one of the plurality of photodetectors;
a second terminal coupled to one of the plurality of nodes; and
a body between the first terminal and the second terminal; and
a control terminal electrically coupled to the body, wherein the transfer of the electrons occurs through the body between the first terminal and the second terminal in response to a control voltage of sufficient value applied to the control terminal, and in an absence of the control voltage the control terminal creates an electric field tending to repel the electrons from a portion of the body by the control terminal;
a plurality of reset devices, wherein each of the plurality of nodes has a corresponding reset device of the plurality of reset devices, and said each of the plurality of nodes is reset when the corresponding reset device is active;
row and column circuitry; and
a plurality of signal devices coupling the plurality of nodes to the row and column circuitry.
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Specification