US 11,658,201 B2
Dual conversion gain image sensor pixels
Gang Chen, San Jose, CA (US); Zhi Hao, Shanghai (CN); and Yi Zhang, Shanghai (CN)
Assigned to SILEAD INC., Shanghai (CN)
Filed by Silead Inc., Shanghai (CN)
Filed on Aug. 25, 2021, as Appl. No. 17/411,531.
Prior Publication US 2023/0064181 A1, Mar. 2, 2023
Int. Cl. H04N 5/355 (2011.01); H01L 27/146 (2006.01); H04N 5/3745 (2011.01); H01L 27/148 (2006.01)
CPC H01L 27/14643 (2013.01) [H01L 27/14603 (2013.01); H01L 27/14612 (2013.01); H01L 27/14831 (2013.01); H04N 5/3559 (2013.01); H04N 5/3745 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An image sensor device, comprising:
a photosensitive device configured to generate charges in response to incident light;
a floating diffusion region electrically coupled to the photosensitive device and configured to store the charges; and
a gain conversion circuit, wherein the gain conversion circuit includes:
a switch transistor having a first terminal, a second terminal, and a control terminal, wherein the first terminal is electrically coupled to the floating diffusion region,
a first capacitive element including a third terminal and a fourth terminal, the third terminal being electrically coupled to the second terminal, the fourth terminal being electrically coupled to a reference voltage, and
a second capacitive element electrically coupled to the first capacitive element in parallel,
wherein the first capacitive element comprises a first doped portion in a semiconductor substrate, and the first doped portion is disposed in an active region extending from the floating diffusion region,
wherein the floating diffusion region includes a third capacitive element associated with a second doped portion in the semiconductor substrate, and
wherein a capacitance of the second capacitive element is greater than a capacitance of the first capacitive element, and the capacitance of the first capacitive element is greater than a capacitance of the third capacitive element.