IMAGING DEVICE

• US 20170214873A1
• Filed: 01/16/2017
• Published: 07/27/2017
• Est. Priority Date: 01/22/2016
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Intellectual Property Management Co., Ltd. (Panasonic Holdings Corporation)
• Inventors: NISHIMURA, KAZUKO, MURAKAMI, MASASHI, TAMAKI, TOKUHIKO
• Granted Patent: US 10,375,332 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 27/14614 having a special gate structure
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H04N 25/585 with pixels having different sensitivities within the sensor, e.g. fast or slow pixels or pixels having different sizes
• CPC Class Codes: H04N 25/62 Detection or reduction of noise due to excess charges produced by the exposure, e.g. smear, blooming, ghost image, crosstalk or leakage between pixels
• CPC Class Codes: H04N 25/65 applied to reset noise, e.g. KTC noise related to CMOS structures by techniques other than CDS
• CPC Class Codes: H04N 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/77 Pixel circuitry, e.g. memories, A/D converters, pixel amplifiers, shared circuits or shared components
• CPC Class Codes: H04N 25/778 comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself

Abstract

An imaging device includes: a first pixel cell including a first photoelectric converter that generates a first signal by photoelectric conversion, and a first signal detection circuit that is electrically connected to the first photoelectric converter and detects the first signal; and a second pixel cell including a second photoelectric converter that generates a second signal by photoelectric conversion, and a second signal detection circuit that is electrically connected to the second photoelectric converter and detects the second signal. A sensitivity of the first pixel cell is higher than a sensitivity of the second pixel cell. A circuit configuration of the first signal detection circuit is different from a circuit configuration of the second signal detection circuit.

Claims

1. An imaging device comprising:

a first pixel cell including

a first photoelectric converter that generates a first signal by photoelectric conversion, and

a first signal detection circuit that is electrically connected to the first photoelectric converter and detects the first signal; and

a second pixel cell including

a second photoelectric converter that generates a second signal by photoelectric conversion, and

a second signal detection circuit that is electrically connected to the second photoelectric converter and detects the second signal, wherein

a sensitivity of the first pixel cell is higher than a sensitivity of the second pixel cell, and

a circuit configuration of the first signal detection circuit is different from a circuit configuration of the second signal detection circuit.

2. The imaging device according to claim 1, wherein the first signal detection circuit reduces random noise more than the second signal detection circuit does.

3. The imaging device according to claim 1, wherein a number of one or more transistors included in the first signal detection circuit is larger than a number of zero or more transistors included in the second signal detection circuit.

4. The imaging device according to claim 1, wherein a number of one or more capacitive elements included in the first signal detection circuit is larger than a number of zero or more capacitive elements included in the second signal detection circuit.

5. The imaging device according to claim 1, wherein

the first photoelectric converter includes a first pixel electrode and a first photoelectric conversion region that is in contact with the first pixel electrode;

the second photoelectric converter includes a second pixel electrode and a second photoelectric conversion region that is in contact with the second pixel electrode;

the first signal detection circuit includes a first amplifier transistor that detects the first signal, a gate of the first amplifier transistor being electrically connected to the first pixel electrode;

the second signal detection circuit includes a second amplifier transistor that detects the second signal, a gate of the second amplifier transistor being electrically connected to the second pixel electrode; and

a gate width of the gate of the first amplifier transistor is larger than a gate width of the gate of the second amplifier transistor.

6. The imaging device according to claim 1, wherein

the first photoelectric converter includes a first pixel electrode and a first photoelectric conversion region that is in contact with the first pixel electrode;

the second photoelectric converter includes a second pixel electrode and a second photoelectric conversion region that is in contact with the second pixel electrode;

the first signal detection circuit includes a first reset transistor that resets the first signal, one of a source and a drain of the first reset transistor being electrically connected to the first pixel electrode;

the second signal detection circuit includes a second reset transistor that resets the second signal, one of a source and a drain of the second reset transistor being electrically connected to the second pixel electrode; and

a gate length of a gate of the first reset transistor is larger than a gate length of a gate of the second reset transistor.

7. The imaging device according to claim 1, wherein

the second photoelectric converter includes a second pixel electrode and a second photoelectric conversion region that is in contact with the second pixel electrode;

and

the second signal detection circuit includes a first capacitive element that is electrically connected to the second pixel electrode and accumulates at least a part of the second signal.

8. The imaging device according to claim 1, further comprising a first feedback circuit including an inverting amplifier, wherein

the first photoelectric converter includes a first pixel electrode and a first photoelectric conversion region that is in contact with the first pixel electrode,

the first signal detection circuit includes a first amplifier transistor that detects the first signal and a first reset transistor that resets the first signal, a gate of the first amplifier transistor being electrically connected to the first pixel electrode, one of a source and a drain of the first reset transistor being electrically connected to the first pixel electrode, and

the first feedback circuit forms a feedback path for negatively feeding back a voltage of the first pixel electrode via the first amplifier transistor, the inverting amplifier, and the first reset transistor.

9. The imaging device according to claim 8, wherein

the first signal detection circuit further includes

a first capacitive element one end of which is electrically connected to the first pixel electrode,

a second capacitive element one end of which is electrically connected to the other end of the first capacitive element, a reference voltage being applied to the other end of the second capacitive element, a capacitance value of the second capacitive element being larger than a capacitance value of the first capacitive element, and

a first band control transistor one of a source and a drain of which is connected to the other end of the first capacitive element;

wherein

the first feedback circuit forms a feedback path for negatively feeding back a voltage of the first pixel electrode via the first amplifier transistor, the inverting amplifier, the first band control transistor, and the first capacitive element.

10. The imaging device according to claim 9, wherein the other of the source and the drain of the first reset transistor is electrically connected to the one of the source and the drain of the first band control transistor.

11. The imaging device according to claim 9, wherein the other of the source and the drain of the first reset transistor is electrically connected to the other of the source and the drain of the first band control transistor.

12. The imaging device according to claim 1, further comprising a first feedback circuit, wherein

the first photoelectric converter includes a first pixel electrode and a first photoelectric conversion region that is in contact with the first pixel electrode,

the first signal detection circuit includes

a first amplifier transistor that detects the first signal, a gate of the first amplifier transistor is electrically connected to the first pixel electrode,

a first reset transistor that resets the first signal, one of a source and a drain of the first reset transistor being electrically connected to the first pixel electrode,

a first capacitive element one end of which is electrically connected to the first pixel electrode,

a second capacitive element one end of which is electrically connected to the other end of the first capacitive element, a reference voltage being applied to the other end of the second capacitive element, a capacitance value of the second capacitive element being larger than a capacitance value of the first capacitive element, and

a first band control transistor one of a source and a drain of which is connected to the other end of the first capacitive element,

one of a source and a drain of the first amplifier transistor is electrically connected to the other of the source and the drain of the first band control transistor, and

the first feedback circuit forms a feedback path for negatively feeding back a voltage of the first pixel electrode via the first amplifier transistor, the first band control transistor, and the first capacitive element.

13. The imaging device according to claim 12, wherein the other of the source and the drain of the first reset transistor is electrically connected to the one of the source and the drain of the first band control transistor.

14. The imaging device according to claim 12, wherein the other of the source and the drain of the first reset transistor is electrically connected to the other of the source and the drain of the first band control transistor.

15. The imaging device according to claim 1, further comprising a first feedback circuit, wherein

the first photoelectric converter includes a first pixel electrode and a first photoelectric conversion region that is in contact with the first pixel electrode,

the first signal detection circuit includes

a first amplifier transistor that detects the first signal, a gate of the first amplifier transistor being electrically connected to the first pixel electrode,

a first reset transistor that resets the first signal, one of a source and a drain of the first reset transistor being electrically connected to the first pixel electrode,

a first capacitive element, one end of the first capacitive element being electrically connected to the first pixel electrode,

a second capacitive element one end of which is electrically connected to the other end of the first capacitive element, a reference voltage being applied to the other end of the second capacitive element, a capacitance value of the second capacitive element being larger than a capacitance value of the first capacitive element,

a first band control transistor one of a source and a drain of which is connected to the other end of the first capacitive element, and

a first selection transistor one of a source and a drain of which is electrically connected to one of a source and a drain of the first amplifier transistor,

the other of the source and the drain of the first selection transistor is electrically connected to the other of the source and the drain of the first band control transistor, and

the first feedback circuit forms a feedback path for negatively feeding back a voltage of the first pixel electrode via the first amplifier transistor, the first selection transistor, the first band control transistor, and the first capacitive element.

16. The imaging device according to claim 15, wherein the other of the source and the drain of the first reset transistor is electrically connected to the one of the source and the drain of the first band control transistor.

17. The imaging device according to claim 15, wherein the other of the source and the drain of the first reset transistor is electrically connected to the other of the source and the drain of the first band control transistor.

18. The imaging device according to claim 1, wherein

the first photoelectric converter includes a first pixel electrode and a first photoelectric conversion region that is in contact with the first pixel electrode;

the first signal detection circuit includes

a first amplifier transistor that detects the first signal, a gate of the first amplifier transistor being electrically connected to the first pixel electrode,

a first reset transistor that resets the first signal, one of a source and a drain of the first reset transistor being electrically connected to the first pixel electrode,

a first capacitive element one end of which is electrically connected to the first pixel electrode,

a second capacitive element one end of which is electrically connected to the other end of the first capacitive element, a reference voltage being applied to the other end of the second capacitive element, a capacitance value of the second capacitive element being larger than a capacitance value of the first capacitive element,

a first band control transistor one of a source and a drain of which is connected to the other end of the first capacitive element, and

a first feedback circuit;

a gate of the first band control transistor is electrically connected to the first pixel electrode; and

the first feedback circuit forms a feedback path for negatively feeding back a voltage of the first pixel electrode via the first band control transistor and the first capacitive element.

19. The imaging device according to claim 18, wherein the other of the source and the drain of the first reset transistor is electrically connected to the one of the source and the drain of the first band control transistor.

20. The imaging device according to claim 18, wherein the other end of the source and the drain of the first reset transistor is electrically connected to the other of the source and the drain of the first band control transistor.