Optical isolation of optically black pixels in image sensors

摘要

Optical isolation is provided for optically black pixels in image sensors. Image sensors, such as backside illumination (BSI) image sensors, may have an active pixel array and an array having optically black pixels. Isolation structures such as a metal wall may be formed in a dielectric stack between an active pixel array and optically black pixels. Patterned shallow trench isolation regions or polysilicon regions may be formed in a substrate between an active pixel array and optically black pixels. An absorption region such as a germanium-doped absorption region may be formed in a substrate between an active pixel array and optically black pixels. Optical isolation and absorption regions may be formed in a ring surrounding an active pixel array.

主权项

1. A backside illumination image sensor, comprising:
an active pixel region having a first plurality of pixels; an optically black pixel region having a second plurality of pixels covered by an opaque layer; a metal barrier between the active pixel region and the optically black pixel region, wherein the metal barrier extends vertically through a plurality of dielectric layers and metal interconnect layers.