公开(公告)号：US20210193704A1

公开(公告)日：2021-06-24

申请号：US16725687

申请日：2019-12-23

Applicant: OMNIVISION TECHNOLOGIES, INC.

Inventor： Shiyu Sun

IPC: H01L27/146 ,  H01L21/762 ,  H01L21/285 ,  H01L21/02

Abstract: A method for forming a deep trench isolation structure for a CMOS image sensor includes providing a trench that extends from a first side toward a second side of a semiconductor substrate. The trench has an opening on the first side and a bottom and sides. A conformal layer of B-doped oxide is deposited on the bottom and sides of the trench and is less than half a width of the trench leaving a depthwise recess in the trench. A second material is deposited on the conformal layer of B-doped oxide in the trench filling the recess in the trench to the first side. The conformal layer of B-doped oxide is annealed driving boron from the conformal layer of B-doped oxide to the semiconductor substrate forming a B-doped region as a passivation layer juxtaposed next to the conformal layer of B-doped oxide having negative fixed charges.