Image sensor with doped semiconductor region for reducing image noise

摘要

A backside illuminated image sensor includes a semiconductor layer having a back-side surface and a front-side surface. The semiconductor layer includes a pixel array region including a plurality of photodiodes configured to receive image light through the back-side surface of the semiconductor layer. The semiconductor layer also includes a peripheral circuit region including peripheral circuit elements for operating the plurality of photodiodes that borders the pixel array region. The peripheral circuit elements emit photons. The peripheral circuit region also includes a doped semiconductor region positioned to absorb the photons emitted by the peripheral circuit elements to prevent the plurality of photodiodes from receiving the photons.

主权项

1. A backside illuminated image sensor comprising:
a semiconductor layer having a back-side surface and a front-side surface, wherein the semiconductor layer includes silicon, and wherein the semiconductor layer comprises:
a pixel array region including a plurality of photodiodes configured to receive image light through the back-side surface of the semiconductor layer; anda peripheral circuit region including peripheral circuit elements for operating the plurality of photodiodes, wherein the peripheral circuit elements emit photons in a non-visible wavelength, and wherein the peripheral circuit region borders the pixel array region, the peripheral circuit region further including a doped semiconductor region doped to a level to absorb the photons emitted by the peripheral circuit elements to prevent the plurality of photodiodes from receiving the photons, wherein the doped semiconductor region is disposed along the back-side surface of the semiconductor layer above the peripheral circuit elements with no part of the doped semiconductor region above the pixel array region.