US-20260129312-A1 - IMAGE SENSING DEVICE

Abstract

Image sensing devices capable of implementing multiple gains are disclosed. In an embodiment, an image sensing device includes a first pixel including first and second dual conversion gain (DCG) transistors that adjust capacitance of a first floating diffusion region shared by a plurality of pixels included in a first pixel group; and a second pixel including third and fourth DCG transistors that adjust capacitance of a second floating diffusion region shared by a plurality of pixels included in a second pixel group arranged at one side of the first pixel group. A gate of the first DCG transistor and a gate of the second DCG transistor are arranged closer to the second pixel from a center of the first pixel, and a gate of the third DCG transistor and a gate of the fourth DCG transistor are arranged closer to the first pixel from a center of the second pixel.

Inventors

• Sung Ho Choi
• Hee Dong Kim
• Hyeon Jeong LEE
• Hyun Soo Lim
• Hyo Jun KWON
• Da Yea BAEK

Assignees

• SK Hynix Inc.

Dates

Publication Date

20260507

Application Date

20250801

Priority Date

20241101

Claims (20)

1. 1 . An image sensing device comprising: a pixel array of pixels for sensing incident light to capture images carried by the incident light, wherein the pixel array includes a first pixel group of pixels and a second pixel group of pixels arranged at one side of and adjacent to the first pixel group, wherein the first pixel group includes a first pixel including first and second dual conversion gain (DCG) transistors configured to adjust a capacitance of a first floating diffusion region shared by a plurality of pixels included in the first pixel group, and wherein the second pixel group includes a second pixel including third and fourth DCG transistors configured to adjust a capacitance of a second floating diffusion region shared by a plurality of pixels included in the second pixel group, wherein a gate of the first DCG transistor and a gate of the second DCG transistor are arranged such that a distance between the gates of the first and second DCG transistors and the second pixel is shorter than a distance between the second pixel and a center of the first pixel, and a gate of the third DCG transistor and a gate of the fourth DCG transistor are arranged such that a distance between the gates of the third and fourth DCG transistors and the first pixel is shorter than a distance between the first pixel and a center of the second pixel.
2. 2 . The image sensing device according to claim 1 , further comprising: a first dual conversion gain (DCG) electrical interconnect line configured to electrically connect a terminal of the first DCG transistor to a terminal of the third DCG transistor; and a second DCG electrical interconnect line configured to electrically connect a terminal of the second DCG transistor to a terminal of the fourth DCG transistor.
3. 3 . The image sensing device according to claim 2 , wherein: the first pixel includes: first and second photoelectric conversion elements configured to generate photocharges in response to incident light, and the second pixel includes: third and fourth photoelectric conversion elements configured to generate photocharges in response to the incident light.
4. 4 . The image sensing device according to claim 3 , further comprising: a pixel isolation structure disposed between the first and second photoelectric conversion elements and between the third and fourth photoelectric conversion elements.
5. 5 . The image sensing device according to claim 3 , wherein the gate of the first DCG transistor overlaps the first photoelectric conversion element, the gate of the second DCG transistor overlaps the second photoelectric conversion element, the gate of the third DCG transistor overlaps the third photoelectric conversion element, and the gate of the fourth DCG transistor overlaps the fourth photoelectric conversion element.
6. 6 . The image sensing device according to claim 3 , wherein: the first pixel further includes: a first transfer transistor configured to move the photocharges generated by the first photoelectric conversion element to the first floating diffusion region; and a second transfer transistor configured to move the photocharges generated by the second photoelectric conversion element to the first floating diffusion region, and the second pixel further includes: a third transfer transistor configured to move the photocharges generated by the third photoelectric conversion element to the second floating diffusion region; and a fourth transfer transistor configured to move the photocharges generated by the fourth photoelectric conversion element to the second floating diffusion region.
7. 7 . The image sensing device according to claim 1 , wherein: the first pixel group further includes: a first drive transistor configured to amplify an electrical signal corresponding to photocharges stored in the first floating diffusion region, and the second pixel group further includes: a second drive transistor configured to amplify an electrical signal corresponding to photocharges stored in the second floating diffusion region.
8. 8 . The image sensing device according to claim 7 , wherein: the first pixel group further includes: a first selection transistor configured to selectively output an electrical signal amplified by the first drive transistor, and the second pixel group further includes: a second selection transistor configured to selectively output an electrical signal amplified by the second drive transistor.
9. 9 . The image sensing device according to claim 1 , wherein: the first pixel group includes: a first reset transistor configured to reset the first floating diffusion region, and the second pixel group includes: a second reset transistor configured to reset the second floating diffusion region.
10. 10 . The image sensing device according to claim 1 , further comprising: a third dual conversion gain (DCG) electrical interconnect line configured to electrically connect a terminal of the first DCG transistor to a terminal of the second DCG transistor; and a fourth DCG electrical interconnect line configured to electrically connect a terminal of the third DCG transistor to a terminal of the fourth DCG transistor.
11. 11 . The image sensing device according to claim 1 , wherein: the first floating diffusion region is electrically connected to a terminal of the first DCG transistor, and the second floating diffusion region is electrically connected to a terminal of the third DCG transistor.
12. 12 . An image sensing device comprising: a first pixel including first and second photoelectric conversion elements configured to generate photocharges in response to incident light; a second pixel including third and fourth photoelectric conversion elements configured to generate photocharges in response to the incident light, the second pixel being in contact with a side surface of the first pixel; a third pixel including fifth and sixth photoelectric conversion elements configured to generate photocharges in response to the incident light, a side surface of the third pixel being in contact with an opposite side surface of the first pixel; and a fourth pixel including seventh and eighth photoelectric conversion elements configured to generate photocharges in response to the incident light, the fourth pixel being in contact with an opposite side surface of the third pixel, wherein the first pixel includes: first and second dual conversion gain (DCG) transistors configured to adjust conversion gains of the first and second pixels and are arranged such that a distance between the first and second DCG transistors and the side surface of the third pixel is shorter than a distance between the first and second DCG transistors and the side surface of the first pixel, and the third pixel includes: third and fourth DCG transistors configured to adjust conversion gains of the third and fourth pixels and are arranged such that a distance between the third and fourth DCG transistors and the opposite side surface of the first pixel is shorter than a distance between the third and fourth DCG transistors and the opposite side surface of the third pixel.
13. 13 . The image sensing device according to claim 12 , wherein: one terminal of the first DCG transistor and one terminal of the third DCG transistor are electrically connected to each other, and one terminal of the second DCG transistor and one terminal of the fourth DCG transistor are electrically connected to each other.
14. 14 . The image sensing device according to claim 13 , wherein: the first pixel includes: a first floating diffusion region configured to store photocharges generated by the first photoelectric conversion element and the second photoelectric conversion element, and the third pixel includes: a second floating diffusion region configured to store photocharges generated by the fifth photoelectric conversion element and the sixth photoelectric conversion element.
15. 15 . The image sensing device according to claim 14 , wherein: another terminal of the first DCG transistor is electrically connected to the first floating diffusion region, and another terminal of the third DCG transistor is electrically connected to the second floating diffusion region.
16. 16 . The image sensing device according to claim 14 , wherein: the one terminal of the first DCG transistor is electrically connected to another terminal of the second DCG transistor, and the one terminal of the third DCG transistor is electrically connected to another terminal of the fourth DCG transistor.
17. 17 . The image sensing device according to claim 12 , wherein: when all of the first to fourth DCG transistors are turned off, the first and second pixels have a high conversion gain higher than a middle conversion gain, when the first DCG transistor is turned on and the second to fourth DCG transistors are turned off, the first pixel and the second pixel have the middle conversion gain higher than a low conversion gain and lower than the high conversion gain, and when all of the first to fourth DCG transistors are turned on, the first pixel and the second pixel have the low conversion gain lower than the high conversion gain and the middle conversion gain.
18. 18 . The image sensing device according to claim 17 , wherein: the middle conversion gain is twice the low conversion gain.
19. 19 . The image sensing device according to claim 17 , wherein: the high conversion gain is eight times the low conversion gain.
20. 20 . The image sensing device according to claim 17 , wherein: when all of the first to fourth DCG transistors are turned off, the third and fourth pixels have a high conversion gain higher than a middle conversion gain, when the third DCG transistor is turned on and the first, second, and fourth DCG transistors are turned off, the third and fourth pixels have the middle conversion gain higher than a low conversion gain and lower than the high conversion gain, and when all of the first to fourth DCG transistors are turned on, the third and fourth pixels have the low conversion gain lower than the high conversion gain and the middle conversion gain.

Description

CROSS-REFERENCE TO RELATED APPLICATION This patent document claims the priority and benefits of Korean patent application No. 10-2024-0153645, filed on Nov. 1, 2024, the disclosure of which is incorporated herein by reference in its entirety as part of the disclosure of this patent document. TECHNICAL FIELD The technology and embodiments disclosed in this patent document generally relate to an image sensing device, and more particularly to an image sensing device capable of implementing multiple gains. BACKGROUND An image sensing device can capture optical images by converting light into electrical signals using a photosensitive semiconductor material that reacts to light. With advancements in industries such as automotive, medical, computer and communication industries, the demand for high-performance image sensing devices is growing across various fields, such as smartphones, digital cameras, game machines, IoT (Internet of Things), robots, security cameras and medical micro cameras. The image sensing device may be roughly divided charge coupled device (CCD) image sensing devices and complementary metal oxide semiconductor (CMOS) image sensing devices. CCD image sensing devices offer a better image quality, but they tend to consume more power and are larger as compared to CMOS image sensing devices. CMOS image sensing devices are smaller in size and consume less power than CCD image sensing devices. Furthermore, CMOS image sensing devices are fabricated using the CMOS fabrication technology, and thus photosensitive elements and other signal processing circuitry can be integrated into a single chip, enabling the production of miniaturized image sensing devices at a lower cost. For these reasons, CMOS image sensing devices are being developed for many applications including mobile devices. SUMMARY Various embodiments of the disclosed technology relate to an image sensing device capable of reducing junction capacitance and implementing multiple conversion gains when two different dual conversion gain (DCG) transistors are electrically connected to each other. Various embodiments of the disclosed technology relate to an image sensing device capable of more precisely adjusting the ratio of multiple conversion gains. In an embodiment of the disclosed technology, an image sensing device may include a pixel array of pixels for sensing incident light to capture images carried by the incident light, wherein the pixel array includes a first pixel group of pixels and a second pixel group of pixels arranged at one side of and adjacent to the first pixel group, wherein the first pixel group includes a first pixel including first and second dual conversion gain (DCG) transistors configured to adjust a capacitance of a first floating diffusion region shared by a plurality of pixels included in the first pixel group, and wherein the second pixel group includes a second pixel including third and fourth DCG transistors configured to adjust a capacitance of a second floating diffusion region shared by a plurality of pixels included in the second pixel group, wherein a gate of the first DCG transistor and a gate of the second DCG transistor are arranged such that a distance between the gates of the first and second DCG transistors and the second pixel is shorter than a distance between the second pixel and a center of the first pixel, and a gate of the third DCG transistor and a gate of the fourth DCG transistor are arranged such that a distance between the gates of the third and fourth DCG transistors and the first pixel is shorter than a distance between the first pixel and a center of the second pixel. In some implementations, the image sensing device may further include: a first dual conversion gain (DCG) electrical interconnect line configured to electrically connect a terminal of the first DCG transistor to a terminal of the third DCG transistor; and a second DCG electrical interconnect line configured to electrically connect a terminal of the second DCG transistor to a terminal of the fourth DCG transistor. In some implementations, the first pixel may include first and second photoelectric conversion elements configured to generate photocharges in response to incident light, and the second pixel includes: third and fourth photoelectric conversion elements configured to generate photocharges in response to the incident light. In some implementations, the image sensing device may further include: a pixel isolation structure disposed between the first and second photoelectric conversion elements and between the third and fourth photoelectric conversion elements. In some implementations, the gate of the first DCG transistor may overlap the first photoelectric conversion element; the gate of the second DCG transistor may overlap the second photoelectric conversion element; the gate of the third DCG transistor may overlap the third photoelectric conversion element; and the gate of the fourth DCG transistor may overlap the fo