US 12,484,327 B2
Pre-cleaning for a deep trench isolation structure in a pixel sensor
Yu-Hung Cheng, Tainan (TW); Yu-Siang Fang, Tainan (TW); and Ching I Li, Tainan (TW)
Assigned to Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed on May 17, 2022, as Appl. No. 17/663,801.
Prior Publication US 2023/0378215 A1, Nov. 23, 2023
Int. Cl. H10F 39/00 (2025.01); H01L 21/306 (2006.01)
CPC H10F 39/807 (2025.01) [H01L 21/30604 (2013.01); H10F 39/014 (2025.01)] 20 Claims
OG exemplary drawing
 
1. A method, comprising:
forming, in a substrate, a photodiode for a pixel sensor of a pixel array;
forming, in the substrate, a drain region for the pixel sensor;
forming, in the substrate, a trench adjacent to the photodiode and the drain region;
performing a deposition operation to deposit a germanium layer on the trench,
wherein germanium of the germanium layer reacts with oxygen in the trench to form a germanium oxide (GeOx) during a stabilization duration, and
wherein the germanium of the germanium layer reacts with silicon in the trench to form a monolayer;
performing an etch operation to remove the monolayer after the stabilization duration;
forming, after performing the etch operation, a boron layer on sidewalls of the trench and on a bottom surface of the trench; and
filling the trench with a dielectric material over the boron layer to form a deep trench isolation (DTI) structure.