	US 12,191,327 B2
	CMOS image sensor having indented photodiode structure
Chia-Yu Wei, Tainan (TW); Hsin-Chi Chen, Tainan (TW); Kuo-Cheng Lee, Tainan (TW); Ping-Hao Lin, Tainan (TW); Hsun-Ying Huang, Tainan (TW); Yen-Liang Lin, Tainan (TW); and Yu Ting Kao, Tainan (TW)
Assigned to Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsin-Chu (TW)
Filed on Nov. 2, 2023, as Appl. No. 18/500,357.
Application 18/500,357 is a continuation of application No. 17/528,542, filed on Nov. 17, 2021, granted, now 11,843,007.
Application 17/528,542 is a continuation of application No. 16/662,453, filed on Oct. 24, 2019, granted, now 11,183,523, issued on Nov. 23, 2021.
Application 16/662,453 is a continuation of application No. 16/017,078, filed on Jun. 25, 2018, granted, now 10,790,321, issued on Sep. 29, 2020.
Claims priority of provisional application 62/565,315, filed on Sep. 29, 2017.
Prior Publication US 2024/0063234 A1, Feb. 22, 2024
Int. Cl. H01L 27/146 (2006.01); H01L 29/78 (2006.01)

CPC H01L 27/14607 (2013.01) [H01L 27/1461 (2013.01); H01L 27/14612 (2013.01); H01L 27/14621 (2013.01); H01L 27/1463 (2013.01); H01L 27/14636 (2013.01); H01L 27/14641 (2013.01); H01L 27/14689 (2013.01); H01L 27/14603 (2013.01); H01L 27/14627 (2013.01); H01L 27/14632 (2013.01); H01L 27/14638 (2013.01); H01L 27/1464 (2013.01); H01L 27/14645 (2013.01); H01L 27/14647 (2013.01); H01L 27/14687 (2013.01); H01L 29/7827 (2013.01)]

20 Claims

1. A method of forming an image sensor, comprising:

forming a transfer gate over a substrate, wherein the substrate is doped with a first doping type;

forming a floating diffusion region within the substrate;

forming a masking layer over the substrate, the masking layer having a circumference including a first recessed portion spaced apart from a second recessed portion from a top-down view, the first recessed portion and the second recessed portion are symmetrically distributed across a line that extends through centers of both the transfer gate and the floating diffusion region; and

with the masking layer in place, performing a plurality of implantation processes to form a photo detecting column within the substrate at one side of the transfer gate opposing to the floating diffusion region;

wherein the photo detecting column and the substrate are in contact with each other at a junction interface and configured as a photodiode structure to convert radiation that enters the substrate into an electrical signal.