Complementary metal-oxide-semiconductor image sensors

Patent metadata

Field	Value
Publication number	US-10950650-B2
Application number	US-202016750608-A
Country	US
Kind code	B2
Filing date	Jan 23, 2020
Priority date	Aug 11, 2014
Publication date	Mar 16, 2021
Grant date	Mar 16, 2021

Abstract

A CMOS image sensor includes a substrate and at least one device isolation region in the substrate and defining first and second pixel regions and first and second active portions in each of the first and second pixel regions. A reset and select transistor gates are disposed in the first pixel region, while a source follower transistor gate is disposed in the second pixel region, such that pixels in the first and second pixel regions share the reset, select and source follower transistors. A length of the source follower transistor gate may be greater than lengths of the reset and selection transistor gates.

First claim

What is claimed is:

1. An image sensor comprising:
a substrate having a first surface and a second surface facing each other;
a first photoelectric conversion element in the substrate;
a second photoelectric conversion element in the substrate;
a first gate having a first length in a first direction;
a second gate having a second length in the first direction;
a common floating diffusion region;
a third gate having a third length in the first direction greater than the first length;
a first contact disposed directly adjacent to the first gate;
a second contact disposed directly adjacent to the second gate;
a first transfer gate configured to transfer a first charge accumulated in the first photoelectric conversion element to the common floating diffusion region; and
a second transfer gate configured to transfer a second charge accumulated in the second photoelectric conversion element to the common floating diffusion region,
wherein the second contact, the second gate, the first gate, and the first contact are sequentially arranged along the first direction,
wherein the second gate, the first transfer gate, and the second transfer gate are arranged along a second direction perpendicular to the first direction, and
wherein the first, second, and third gates are connected both to the first and second photoelectric conversion elements.

2. The image sensor of claim 1 , further comprising a first micro-lens on the first photoelectric conversion element and a second micro-lens on the second photoelectric conversion element.

3. The image sensor of claim 2 , wherein the first gate, the first transfer gate, the second transfer gate, and the third gate are arranged along the second direction.

4. The image sensor of claim 3 , further comprising:
a first isolation between the first photoelectric conversion element and the second photoelectric conversion element; and
an air gap formed in the first isolation.

5. The image sensor of claim 4 , further comprising:
a second isolation in the substrate formed from the first surface, and
wherein the first micro-lens is disposed on the second surface.

6. The image sensor of claim 4 , further comprising:
a third contact right adjacent to the third gate; and
a fourth contact right adjacent to the third gate,
wherein the fourth contact, the third gate, and the third contact are sequentially arranged along the first direction.

7. The image sensor of claim 6 , wherein the second contact and the fourth contact are aligned in the second direction.

8. The image sensor of claim 6 , wherein the first length is different from the second length.

9. The image sensor of claim 8 , wherein the third length is different from the second length.

10. The image sensor of claim 9 , wherein the second contact and the fourth contact are aligned in the second direction.

11. An image sensor comprising:
a substrate having a first surface and a second surface facing each other;
a first photoelectric conversion element in the substrate;
a second photoelectric conversion element in the substrate;
a first gate having a first length in a first direction;
a second gate having a second length in the first direction;
a first floating diffusion contact;
a second floating diffusion contact;
a third gate having a third length in the first direction greater than the second length;
a first contact disposed directly adjacent to the first gate;
a second contact disposed directly adjacent to the second gate;
a third contact disposed directly adjacent to the third gate;
a fourth contact disposed on the third gate;
a first transfer gate; and
a second transfer gate,
wherein the second contact, the second gate, the first gate, and the first contact are sequentially arranged along the first direction,
wherein the first contact, the first transfer gate, and the second transfer gate are sequentially arranged along a second direction perpendicular to the first direction,
wherein the third contact is offset from the fourth contact along the first direction, and
wherein the first, second, and third gates are connected to both the first and second photoelectric conversion elements.

12. The image sensor of claim 11 , wherein the first gate, the first transfer gate, the second transfer gate, and the third gate are sequentially arranged along the second direction.

13. The image sensor of claim 12 , further comprising a first micro-lens on the first photoelectric conversion element and a second micro-lens on the second photoelectric conversion element.

14. The image sensor of claim 13 , further comprising:
a first isolation between the first photoelectric conversion element and the second photoelectric conversion element; and
an air gap formed in the first isolation.

15. The image sensor of claim 14 , further comprising a second isolation in the substrate formed from the first surface, and
wherein the first micro-lens is disposed on the second surface.

16. The image sensor of claim 15 , further comprising a fifth contact right adjacent to the third gate, and
wherein the second contact and the fifth contact are vertically aligned along the second direction.

17. The image sensor of claim 15 , wherein the first length is different from the second length.

18. The image sensor of claim 15 , wherein the third length is different from the second length.

19. An image sensor comprising:
a substrate having a first surface and a second surface facing each other;
a first photoelectric conversion element in the substrate;
a second photoelectric conversion element in the substrate;
a selection gate having a first length in a first direction;
a reset gate having a second length in the first direction;
a common floating diffusion region;
a floating diffusion contact connected to the common floating diffusion region;
a source follower gate having a third length in the first direction, the third length is being greater than the first length;
a first contact disposed right adjacent to the selection gate;
a second contact disposed right adjacent to the reset gate;
a first transfer gate configured to transfer a first charge accumulated in the first photoelectric conversion element to the common floating diffusion region; and
a second transfer gate configured to transfer a second charge accumulated in the second photoelectric conversion element to the common floating diffusion region,
wherein the selection gate, the first contact, the reset gate, and the second contact are arranged in the first direction,
wherein the reset gate, the first transfer gate, the common floating diffusion, and the second transfer gate are sequentially arranged in a second direction perpendicular to the first direction, and
wherein the selection gate, the reset gate, and the source follower gate are connected both to the first and second photoelectric conversion elements.

20. The image sensor of claim 19 , further comprising:
a first isolation between the first photoelectric conversion element and the second photoelectric conversion element;
an air gap formed in the first isolation,
a second isolation in the substrate formed from the first surface,
wherein the first micro-lens is disposed on the second surface, and
wherein the floating diffusion contact and the second contact are vertically arranged in the second direction.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Ihara Hisanori

Classifications

• H10F39/8063

  Microlenses · CPC title

• H10F39/8053

  Colour filters · CPC title

• H10F39/80373

  characterised by the gate of the transistor · CPC title

• H10F39/807

  Pixel isolation structures · CPC title

• H10F39/802

  Geometry or disposition of elements in pixels, e.g. address-lines or gate electrodes · CPC title