Patent ID: 11948965
Assignee: OMNIVISION TECHNOLOGIES, INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An uneven-trench pixel cell comprising:
a semiconductor substrate that includes a floating diffusion region and a photodiode region; and, between a front surface and a back surface opposing the front surface of the semiconductor substrate:
(i) a first sidewall surface and a shallow bottom surface defining a shallow trench located between the floating diffusion region and the photodiode region and extending into the semiconductor substrate from the front surface, a distance between the shallow bottom surface and the front surface defining a shallow depth of the shallow trench that exceeds a junction depth of the floating diffusion region relative to the front surface; and
(ii) a second sidewall surface and a deep bottom surface defining a deep trench located between the floating diffusion region and the photodiode region and extending into the semiconductor substrate from the front surface, a distance between the deep bottom surface and the front surface defining a deep depth, of the deep trench, that exceeds the shallow depth;

the distance defining the shallow depth being in a depth direction, the shallow trench and the deep trench being located between the floating diffusion region and the photodiode region in a first direction, the shallow trench being laterally displaced from the deep trench in a second direction that is perpendicular to the first direction, each of the first direction and the second direction being perpendicular to the depth direction.