Imaging device

• US 10,062,718 B2
• Filed: 01/18/2017
• Issued: 08/28/2018
• Est. Priority Date: 01/29/2016
• 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: Shishido, Sanshiro, Murakami, Masashi, Nishimura, Kazuko
• Primary Examiner(s): Chaudhari, Chandra
• Application Number:
  US15/408,593
• Publication Number:
  US 20170221947A1
• Time in Patent Office: 587 Days
• Field of Search: 257258
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14612 involving a transistor
• CPC Class Codes: H01L 27/14627 Microlenses
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers
• CPC Class Codes: H04N 23/50 Constructional details
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 25/57 Control of the dynamic range
• 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 25/75 Circuitry for providing, modifying or processing image signals from the pixel array
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 25/78 Readout circuits for addressed sensors, e.g. output amplifiers or A/D converters

Abstract

In one general aspect, the techniques disclosed here feature an imaging device that includes: a semiconductor substrate; a first pixel cell including a first photoelectric converter in the semiconductor substrate, and a first capacitive element one end of which is electrically connected to the first photoelectric converter; and a second pixel cell including a second photoelectric converter in the semiconductor substrate. An area of the second photoelectric converter is larger than an area of the first photoelectric converter in a plan view.

Claims

1. An imaging device comprising:

a semiconductor substrate;

a first pixel cell including

a first photoelectric converter in the semiconductor substrate, and

a first capacitive element one end of which is electrically connected to the first photoelectric converter; and

a second pixel cell including

a second photoelectric converter in the semiconductor substrate, wherein, an area of the second photoelectric converter is larger than an area of the first photoelectric converter in a plan view,

a number of charges generated in the second pixel cell is greater than a number of charges generated in the first pixel cell when the first and second pixel cells receive incident light, and

a number of saturation charges of the first pixel cell is greater than a number of saturation charges of the second pixel cell.

2. The imaging device according to claim 1, wherein

the first pixel cell further includes a first charge detection circuit electrically connected to the first photoelectric converter;

and

the second pixel cell further includes a second charge detection circuit electrically connected to the second photoelectric converter.

3. The imaging device according to claim 2, wherein

the first charge detection circuit includes a first reset transistor one of a source and a drain of which is electrically connected to the first photoelectric converter;

and

the second charge detection circuit includes a second reset transistor one of a source and a drain of which is electrically connected to the second photoelectric converter.

4. The imaging device according to claim 2, wherein

the first pixel cell includes a first transfer transistor one of a source and a drain of which is electrically connected to the first photoelectric converter;

and

the first charge detection circuit includes

a first floating diffusion electrically connected to the other of the source and the drain of the first transfer transistor, and

a first reset transistor one of a source and a drain of which is electrically connected to first floating diffusion.

5. The imaging device according to claim 2, wherein

the second pixel cell includes a second transfer transistor one of a source and a drain of which is electrically connected to the second photoelectric converter;

and

the second charge detection circuit includes

a second floating diffusion electrically connected to the other of the source and the drain of the second transfer transistor, and

a second reset transistor one of a source and a drain of which is electrically connected to the second floating diffusion.

6. The imaging device according to claim 1, wherein

the second pixel cell includes

a transfer transistor one of a source and a drain of which is electrically connected to the second photoelectric converter;

and

a floating diffusion electrically connected to the other of the source and the drain of the transfer transistor.

7. The imaging device according to claim 1, wherein

the first pixel cell further includes a first transfer transistor one of a source and a drain of which is electrically connected to the first photoelectric converter;

the second pixel cell further includes

a second transfer transistor one of a source and a drain of which is electrically connected to the second photoelectric converter, and

a floating diffusion electrically connected to the other of the source and the drain of the second transfer transistor; and

the floating diffusion is electrically connected to the other of the source and the drain of the first transfer transistor.

8. The imaging device according to claim 7, wherein the second pixel cell further includes a reset transistor one of a source and a drain of which is electrically connected to the floating diffusion.

9. The imaging device according to claim 1, wherein the second pixel cell does not have a capacitive element.

10. The imaging device according to claim 1, wherein a shape of the second photoelectric converter is different from a shape of the first photoelectric converter in the plan view.

11. The imaging device according to claim 1, wherein

the first pixel cell further includes a first microlens located at a light incident side of the first photoelectric converter;

the second pixel cell further includes a second microlens located at a light incident side of the second photoelectric converter; and

a light-collecting area of the second microlens is larger than a light-collecting area of the first microlens.

12. The imaging device according to claim 1, wherein

the first pixel cell and the second pixel cell directly adjoin each other;

the first pixel cell and the second pixel cell further include a common microlens located at a light incident side of the first photoelectric converter and the second photoelectric converter; and

the second photoelectric converter is located on an optical axis of the common microlens.

13. The imaging device according to claim 1, wherein

the first capacitive element includes a first electrode, a second electrode, and an insulator between the first electrode and the second electrode, and

one of the first electrode and the second electrode is electrically connected to the first photoelectric converter.

14. The imaging device according to claim 1, wherein a second storage time when the second pixel cell accumulates a second charge generated in the second photoelectric converter is longer than a first storage time when the first pixel cell accumulates a first charge generated in the first photoelectric converter.

15. The imaging device according to claim 2, wherein the first charge detection circuit detects the first charge at least twice without resetting the first charge, during one frame period.

21. The imaging device according to claim 1, wherein

the first pixel cell and the second pixel cell include a charge detection circuit,

the charge detection circuit includes

a floating diffusion,

a reset transistor one of a source and a drain of which is electrically connected to the floating diffusion, and

an amplification transistor having a gate electrically connected to the floating diffusion,

the first pixel cell further includes a first transfer transistor, the first photoelectric converter being electrically connected to the floating diffusion via the first transfer transistor, and

the second pixel cell further includes a second transfer transistor, the second photoelectric converter being electrically connected to the floating diffusion via the second transfer transistor.

16. An imaging device comprising:

a semiconductor substrate;

a first pixel cell including

a first photoelectric converter that is located in the semiconductor substrate and converts incident light into a first charge,

a first storage capacitance that is electrically connected to the first photoelectric converter and accumulates at least a part of the first charge, and

a first charge detection circuit that is connected to the first storage capacitance and detects the first charge; and

a second pixel cell including

a second photoelectric converter that is located in the semiconductor substrate and converts incident light into a second charge,

a second storage capacitance that is connected to the second photoelectric converter and accumulates at least a part of the second charge, and

a second charge detection circuit that is connected to the second storage capacitance and detects the second charge, wherein

an area of the second photoelectric converter is larger than an area of the first photoelectric converter in a plan view, and

a capacitance value of the first storage capacitance is larger than a capacitance value of the second storage capacitance,

a number of charges generated in the second pixel cell is greater than a number of charges generated in the first pixel cell when the first and second pixel cells receive incident light, and

a number of saturation charges of the first pixel cell is greater than a number of saturation charges of the second pixel cell.

17. The imaging device according to claim 16, wherein

the first storage capacitance includes a capacitive element, and

the second storage capacitance does not include a capacitive element.

18. The imaging device according to claim 16, wherein

the first pixel cell and the second pixel cell directly adjoin each other;

the first pixel cell and the second pixel cell further include a common microlens located at light-incident side of the first photoelectric converter and the second photoelectric converter; and

the second photoelectric converter is located on an optical axis of the common microlens.

19. An imaging device comprising:

a semiconductor substrate;

a first pixel cell including

a first photoelectric converter in the semiconductor substrate, and

a first capacitive element one end of which is electrically connected to the first photoelectric converter; and

a second pixel cell including

a second photoelectric converter in the semiconductor substrate, wherein,

an area of the second photoelectric converter is larger than an area of the first photoelectric converter in a plan view,

the first pixel cell and the second pixel cell directly adjoin each other,

the semiconductor substrate includes a region between the first photoelectric converter and the second photoelectric converter, and

the first capacitive element at least partly overlaps, in the plan view, with the region.

20. The imaging device according to claim 19, wherein the first capacitive element at least partly overlaps, in the plan view, with the second photoelectric converter.